With the Copenhagen climate summit going on this week, one might possibly be forgiven for being just a little cynical at the timing of the UK government's raft of announcements on encouraging people to go greener. This is at the same time as seeking rafts of cuts elsewhere, increasing various taxes and so on in an attempt to halve the uk's deficit within the next 4 years. The BBC news story can be found here .
On the plus side it has to be good news for those who care about moving to sustainable energy sources and reducing usage elsewhere. Amongst the proposals are a boiler scrappage scheme - 125,000 homes will be offered up to 400 pounds to replace old out-dated boilers - although the man from British Gas says there are 4 million old boilers in UK households. From a somewhat selfish point of view I find this of interest since our boiler is old and inefficient. I would love to replace it and save some of the cost of a new boiler at the same time. Having looked at alternatives I see little option (at least in the affordable bracket) at the moment other than to replace our existing boiler with a more efficient condensing model. The question is whether to keep the hot water storage tank for a future rooftop water heating system.
The government is also saying that any electric company car vehicles will be exempt from company car tax for the next 5 years.
The place where it all starts to get misleading is the suggestion that those who have their own wind turbines or solar panels will be able to make on average 900 pounds a year, tax free, by selling excess energy back to the grid. This is not your average householder but those who have enough land to make a serious size installation of turbines or significant acreage of solar panels. We currently use about 7500 kWh of electricity a year - perhaps a little less now - at around 10 pence a unit that is around 750 pounds. Even if the government pays a premium, I would have to generate at least twice that to be able to earn 900 pounds. My calculations for a typical domestic wind turbine shows that we would fall a long way short of continually generating the necessary kW of power for our own needs, let along the 2 kW plus necessary to earn my 900 pounds.
The payback time on a typical wind turbine today is about 12 years in a total 20 year life. Making the income tax free will improve the return, but it won't (or at least shouldn't) encourage small households to go and install their own turbines and solar cells. If someone wishes to be altruistic and get themselves off the grid at whatever cost then fine, but don't be misled by all the fine words.
Wednesday 9 December 2009
Sunday 25 October 2009
Wind turbines, radar and fuel out of thin air!
There is an article on the BBC news website today about the problem of wind turbines causing radar clutter.
This was something I hadn't thought about - although I once had a summer job at what was then Ferranti's Radar Systems Department where the issue of clutter was very much in the engineers' minds. Apparently the problem has been delaying the deployment of significant amounts of wind based energy generation. Qinetiq have come up with a coating for the blades to reduce the problem - although it's not going to completely solve it. As they say, every deployment is different. I imagine the defence industry with all the technology that has been developed to make planes invisible to radar will be in demand to help solve this particular issue.
If one was being cynical, then one might suggest that not flying planes is compatible with deploying new energy generation facilities - but that's unlikely to be popular and I suspect that some of the issue is to do with defence of the realm.
On a slightly different topic, I caught a bit of an edition of James May's big ideas on Dave last night. One of the ideas he explored was the idea of creating fuel out of thin air. There's a group in the desert of Mexico who are looking to use CO2 from the air combined with Hydrogen from the electrolysis of water to create fuel. The program was rather short on science - either because they were dumbing it down or because the proponents have secrets that they don't wish to share. The one thing they did share was that they need to split the CO2 into CO + O - which requires temperatures on the order of 2400 degrees centigrade. They've built a solar furnace to help them do this - and demonstrated cooking sausages and rather more impressively melting steel with it. A bit reminiscent of those science fiction death rays. I'd have to find out more about this - it's not clear how far along the technology really is - but they seemed to suggest that hooking their furnace up to their machine for generating fuel would allow them to generate 2 to 3 (presumably US) gallons per day.
That's not a whole lot - but I wonder how it compares in terms of efficiency with making biofuels? Given that one is trying to reverse an exothermic reaction which gives off a whole lot of energy (when one burns the fuel) - it would seem that it's going to take a whole lot of energy to do the recombination of hydrogen and carbon monoxide to create it in the first place.
This was something I hadn't thought about - although I once had a summer job at what was then Ferranti's Radar Systems Department where the issue of clutter was very much in the engineers' minds. Apparently the problem has been delaying the deployment of significant amounts of wind based energy generation. Qinetiq have come up with a coating for the blades to reduce the problem - although it's not going to completely solve it. As they say, every deployment is different. I imagine the defence industry with all the technology that has been developed to make planes invisible to radar will be in demand to help solve this particular issue.
If one was being cynical, then one might suggest that not flying planes is compatible with deploying new energy generation facilities - but that's unlikely to be popular and I suspect that some of the issue is to do with defence of the realm.
On a slightly different topic, I caught a bit of an edition of James May's big ideas on Dave last night. One of the ideas he explored was the idea of creating fuel out of thin air. There's a group in the desert of Mexico who are looking to use CO2 from the air combined with Hydrogen from the electrolysis of water to create fuel. The program was rather short on science - either because they were dumbing it down or because the proponents have secrets that they don't wish to share. The one thing they did share was that they need to split the CO2 into CO + O - which requires temperatures on the order of 2400 degrees centigrade. They've built a solar furnace to help them do this - and demonstrated cooking sausages and rather more impressively melting steel with it. A bit reminiscent of those science fiction death rays. I'd have to find out more about this - it's not clear how far along the technology really is - but they seemed to suggest that hooking their furnace up to their machine for generating fuel would allow them to generate 2 to 3 (presumably US) gallons per day.
That's not a whole lot - but I wonder how it compares in terms of efficiency with making biofuels? Given that one is trying to reverse an exothermic reaction which gives off a whole lot of energy (when one burns the fuel) - it would seem that it's going to take a whole lot of energy to do the recombination of hydrogen and carbon monoxide to create it in the first place.
Saturday 24 October 2009
Mixed messages and looking ahead...
Governments in democracies have a tough job. They have to balance priorities - which leads to them taking actions that are frankly illogical. If they do things that are unpopular they don't get voted back in.
If one believes man-made global warming is a serious threat - and the warnings of those doing the science should be taken seriously - as the British government at least professes to - then surely one should be taking rapid and urgent action. That would mean educating the population and above all legislating to force us to stop burning fossil fuels without at least capturing all the carbon. This would mean dramatically reducing private car use as well as building large amounts of renewable energy generation and almost certainly a number of nuclear power stations to bridge the gap. In the absence of that we would have to reduce the amount of energy we're consuming for both domestic and industrial purposes. These are likely to unpopular moves until the large majority of citizens are convinced of an impending crisis - by which point it will probably be too late. Even then, they will be unlikely to vote for such measures unless the rest of the industrialised world follows suit or leads the way.
This is a classic prisoner's dilemma - if the UK acts in isolation then our economic prosperity will suffer - and our overall effect on the amount of CO2 in the atmosphere will be negligible. This is the justification for the Kyoto agreement - but if the biggest CO2 producers - in particular the USA - don't sign up, then nothing will happen. Countries in the west (or anywhere else for that matter) don't have a great record on altruism. There is also a great deal of distrust - how do you make sure that everyone is playing by the rules?
The car scrappage scheme is an example of just how illogical things can get. Ideally we want to reduce the number of fossil fuel burning cars on the road to reduce CO2 emissions, pollution and congestion - but the economic prosperity of the country is suffering in a deep recession - so the government wants to stimulate economic activity in an area that has been hit hard. They also need the vehicle duty paid on the 30 million vehicles in the country in order to balance their budgets. Their response is to introduce a scrappage scheme whereby one can trade in one's vehicle, providing it's more than 10 years old, to get a discount on a new car. The argument is that newer cars produce less CO2 than old ones. That might be true depending on what one trades in compared to what one buys to replace it - but the difference is pretty small in the overall scheme of things. If one was forced to buy an electric or even a hybrid vehicle then the argument might be valid - but that's not required. This is just one example - there are plenty of others where government policies conflict.
Looking ahead to when the oil price becomes ridiculously high and we don't have enough bio-fuels to replace it, one can foresee a shift in economic activity. As the cost of transporting goods and people by ship and plane becomes too high, globalisation will be replaced by localisation. Electronic communications links and the internet will stay in place, but countries will regenerate their manufacturing and agricultural industries to bring the supply of goods closer to the consumers. Whether we will be able to generate enough electricity from renewable sources to provide for this industrial need is another question!
If one believes man-made global warming is a serious threat - and the warnings of those doing the science should be taken seriously - as the British government at least professes to - then surely one should be taking rapid and urgent action. That would mean educating the population and above all legislating to force us to stop burning fossil fuels without at least capturing all the carbon. This would mean dramatically reducing private car use as well as building large amounts of renewable energy generation and almost certainly a number of nuclear power stations to bridge the gap. In the absence of that we would have to reduce the amount of energy we're consuming for both domestic and industrial purposes. These are likely to unpopular moves until the large majority of citizens are convinced of an impending crisis - by which point it will probably be too late. Even then, they will be unlikely to vote for such measures unless the rest of the industrialised world follows suit or leads the way.
This is a classic prisoner's dilemma - if the UK acts in isolation then our economic prosperity will suffer - and our overall effect on the amount of CO2 in the atmosphere will be negligible. This is the justification for the Kyoto agreement - but if the biggest CO2 producers - in particular the USA - don't sign up, then nothing will happen. Countries in the west (or anywhere else for that matter) don't have a great record on altruism. There is also a great deal of distrust - how do you make sure that everyone is playing by the rules?
The car scrappage scheme is an example of just how illogical things can get. Ideally we want to reduce the number of fossil fuel burning cars on the road to reduce CO2 emissions, pollution and congestion - but the economic prosperity of the country is suffering in a deep recession - so the government wants to stimulate economic activity in an area that has been hit hard. They also need the vehicle duty paid on the 30 million vehicles in the country in order to balance their budgets. Their response is to introduce a scrappage scheme whereby one can trade in one's vehicle, providing it's more than 10 years old, to get a discount on a new car. The argument is that newer cars produce less CO2 than old ones. That might be true depending on what one trades in compared to what one buys to replace it - but the difference is pretty small in the overall scheme of things. If one was forced to buy an electric or even a hybrid vehicle then the argument might be valid - but that's not required. This is just one example - there are plenty of others where government policies conflict.
Looking ahead to when the oil price becomes ridiculously high and we don't have enough bio-fuels to replace it, one can foresee a shift in economic activity. As the cost of transporting goods and people by ship and plane becomes too high, globalisation will be replaced by localisation. Electronic communications links and the internet will stay in place, but countries will regenerate their manufacturing and agricultural industries to bring the supply of goods closer to the consumers. Whether we will be able to generate enough electricity from renewable sources to provide for this industrial need is another question!
Tuesday 20 October 2009
Hydrogen - Economically Unviable?
I have been reading a book that I referred to in an earlier post called "The Hype About Hydrogen" by Joseph Romm.he examines the case for switching to hydrogen as the energy carrier for the future. Romm worked in the US Department of Energy between 1993 and 1998. From mid 1995 he held the number 2 spot in the office of Energy Efficiency and Renewable Energy. He is well qualified to explain the facts and issues surrounding a potential future hydrogen economy - and there are many. The book is heavily focused on the US, although he does look at Iceland as a place where a hydrogen economy may be viable, primarily because they have excess geo-thermal energy that can be used for the generation of hydrogen.
Romm is convinced that man-made global warming is a real threat. He is equally convinced that there will not be a viable hydrogen based economy for some decades. There are many technical and economic problems to be overcome, which makes current US policy look distinctly flawed.
He primarily investigates the issues surrounding fuel cells. These are devices that take hydrogen in one end (or a substance from which hydrogen can be released), air (providing oxygen) in the other and generate electricity and water. On the face of it clean energy.
Fuel cells are not a new idea - they've been around since the 19th century, but they've never made it into mainstream production, primarily because of the cost and technical issues associated with them.
There are different types of fuel cell - some operate at low temperature, but require to be fed from an external source of hydrogen. These tend to be expensive because they need platinum catalysts. Others operate at high temperature. They can form their own hydrogen from sources such as natural gas - but they take a while to get up to temperature.
There are all sorts of challenges to overcome if a hydrogen based economy is going to be viable. Generation of hydrogen - if the goal is to get off fossil fuels because of the related greenhouse gas emissions, then the CO2 released as a by-product from reforming natural gas needs to be captured and sequestered. If the electrolysis of water is to be used as a source then we need a lot more electrical energy than we currently produce. Another problem is transportation. The energy density of hydrogen per litre is only a third that of petrol - so moving it around using hydrogen is not very efficient. It takes up a lot more space than the equivalent energy volume so requires bigger tanks. It damages pipes that are used to carry it. Being a very small molecule it leaks. There are other health and safety issues that need resolved - for example if it does catch fire it burns with a clear flame making it impossible to see.
Stationary high temperature fuel cells seem to be a potentially viable option for buildings - but the energy and potential CO2 emissions required to generate the hydrogen need to be taken into consideration. If not using renewable energy sources - which are currently in relatively short supply - then fuel cells are generally not more efficient than burning the natural gas in a power station - and a lot more expensive to make.
The bottom line is that there is no set of easy solutions to these problems. Much more research and investment is needed to overcome them. In the meantime, plug in hybrid vehicles and other forms of renewable energy being developed in Europe and elsewhere will rule the roost for some years to come. Romm's plea is for the US government to change its policy and invest more in other forms of energy generation. He doesn't advocate abandoning hydrogen - but suggests it should be seen as a longer term option.
This is an informative book. It presents the numbers and the sources of information used. It's not the easiest of reads - but I'd recommend it for those wanting to be better informed about the subject.
Romm is convinced that man-made global warming is a real threat. He is equally convinced that there will not be a viable hydrogen based economy for some decades. There are many technical and economic problems to be overcome, which makes current US policy look distinctly flawed.
He primarily investigates the issues surrounding fuel cells. These are devices that take hydrogen in one end (or a substance from which hydrogen can be released), air (providing oxygen) in the other and generate electricity and water. On the face of it clean energy.
Fuel cells are not a new idea - they've been around since the 19th century, but they've never made it into mainstream production, primarily because of the cost and technical issues associated with them.
There are different types of fuel cell - some operate at low temperature, but require to be fed from an external source of hydrogen. These tend to be expensive because they need platinum catalysts. Others operate at high temperature. They can form their own hydrogen from sources such as natural gas - but they take a while to get up to temperature.
There are all sorts of challenges to overcome if a hydrogen based economy is going to be viable. Generation of hydrogen - if the goal is to get off fossil fuels because of the related greenhouse gas emissions, then the CO2 released as a by-product from reforming natural gas needs to be captured and sequestered. If the electrolysis of water is to be used as a source then we need a lot more electrical energy than we currently produce. Another problem is transportation. The energy density of hydrogen per litre is only a third that of petrol - so moving it around using hydrogen is not very efficient. It takes up a lot more space than the equivalent energy volume so requires bigger tanks. It damages pipes that are used to carry it. Being a very small molecule it leaks. There are other health and safety issues that need resolved - for example if it does catch fire it burns with a clear flame making it impossible to see.
Stationary high temperature fuel cells seem to be a potentially viable option for buildings - but the energy and potential CO2 emissions required to generate the hydrogen need to be taken into consideration. If not using renewable energy sources - which are currently in relatively short supply - then fuel cells are generally not more efficient than burning the natural gas in a power station - and a lot more expensive to make.
The bottom line is that there is no set of easy solutions to these problems. Much more research and investment is needed to overcome them. In the meantime, plug in hybrid vehicles and other forms of renewable energy being developed in Europe and elsewhere will rule the roost for some years to come. Romm's plea is for the US government to change its policy and invest more in other forms of energy generation. He doesn't advocate abandoning hydrogen - but suggests it should be seen as a longer term option.
This is an informative book. It presents the numbers and the sources of information used. It's not the easiest of reads - but I'd recommend it for those wanting to be better informed about the subject.
Saturday 10 October 2009
Fuel - replacing oil with bio-fuels
The calorific value of petrol is approximately 10 kWh per litre, diesel is about 11 kWh per litre and jet fuel is about 10.5 kWh.
(As a family we currently use about 20 litres per week in our diesel powered people carrier, which translates to approximately 30 kWh per day - that's 50% higher than our electricity usage but much lower than our currently rather excessive gas usage.)
Much is being made of the possibilities of bio-fuels to replace oil based products. These are fuels produced from plants that are processed and converted into oils - which can then be refined in a similar manner to traditional oil to produce petrol, diesel and jet fuel equivalents. I still have a lot to learn about this whole industry - but there are a number of challenges to making this a viable approach for replacing fossil fuels for vehicles.
So called first generation bio-fuels have received a lot of bad press because of the land area that they take up. Farmers have converted land previously used to grow food because of the grants available - resulting in shortages of certain food crops and pushing up food prices. The simple fact of the matter is it takes a LOT of land area to fill a petrol tank. Taking some facts from Mackay's Book, 1 hectare of rape will produce about 1200 litres of bio-diesel. That would run our car for a year at our current rate of consumption. There are about 33 million vehicles registered in the UK - as a first order of approximation we'd need 33 million hectares of rape seed or similar. The only slight problem is that the total area of the UK is only 24 million hectares - and a good portion of that couldn't be farmed! And we haven't even started thinking about planes yet!
There are a couple of easy to read sites promoting the use of bio-fuels for aviation.
http://www.flyonbiofuels.org/?gclid=CJPgjLTHr50CFYIA4wodlnSohQ
http://enviro.aero/Default.aspx
In particular they promote the use of algae as a more efficient and less environmentally damaging way of converting sunlight into fuel. The benefit is that algae don't (necessarily) take up land area that can be better used for food production. They can grow in all sorts of fresh and saltwater environments. The catch however is that to grow them efficiently you need to feed them with concentrated CO2 - of which ironically there is a limited supply.
The aviation industry currently uses about 250 billion litres of aviation fuel (kerosene or Jet-A) per year. The above sites suggest that 1% of this could come from bio-fuels by 2016 and as much as 15% by 2020 and 50% by 2040. These figures seem wildly optimistic to me - although perhaps genetic engineering or some other technique can improve on the efficiency of the growth process. Currently a farm in the US feeding algae with 10% concentrated CO2 produces 0.01 litres per square metre of bio-diesel per day. That's about 36500 litres per hectare per year, or about 30 times more than rape seed. Better, but a long way short of good enough. To get to 125 billion litres just for aviation will require 3 million hectares of algae farms.
(As a family we currently use about 20 litres per week in our diesel powered people carrier, which translates to approximately 30 kWh per day - that's 50% higher than our electricity usage but much lower than our currently rather excessive gas usage.)
Much is being made of the possibilities of bio-fuels to replace oil based products. These are fuels produced from plants that are processed and converted into oils - which can then be refined in a similar manner to traditional oil to produce petrol, diesel and jet fuel equivalents. I still have a lot to learn about this whole industry - but there are a number of challenges to making this a viable approach for replacing fossil fuels for vehicles.
So called first generation bio-fuels have received a lot of bad press because of the land area that they take up. Farmers have converted land previously used to grow food because of the grants available - resulting in shortages of certain food crops and pushing up food prices. The simple fact of the matter is it takes a LOT of land area to fill a petrol tank. Taking some facts from Mackay's Book, 1 hectare of rape will produce about 1200 litres of bio-diesel. That would run our car for a year at our current rate of consumption. There are about 33 million vehicles registered in the UK - as a first order of approximation we'd need 33 million hectares of rape seed or similar. The only slight problem is that the total area of the UK is only 24 million hectares - and a good portion of that couldn't be farmed! And we haven't even started thinking about planes yet!
There are a couple of easy to read sites promoting the use of bio-fuels for aviation.
http://www.flyonbiofuels.org/?gclid=CJPgjLTHr50CFYIA4wodlnSohQ
http://enviro.aero/Default.aspx
In particular they promote the use of algae as a more efficient and less environmentally damaging way of converting sunlight into fuel. The benefit is that algae don't (necessarily) take up land area that can be better used for food production. They can grow in all sorts of fresh and saltwater environments. The catch however is that to grow them efficiently you need to feed them with concentrated CO2 - of which ironically there is a limited supply.
The aviation industry currently uses about 250 billion litres of aviation fuel (kerosene or Jet-A) per year. The above sites suggest that 1% of this could come from bio-fuels by 2016 and as much as 15% by 2020 and 50% by 2040. These figures seem wildly optimistic to me - although perhaps genetic engineering or some other technique can improve on the efficiency of the growth process. Currently a farm in the US feeding algae with 10% concentrated CO2 produces 0.01 litres per square metre of bio-diesel per day. That's about 36500 litres per hectare per year, or about 30 times more than rape seed. Better, but a long way short of good enough. To get to 125 billion litres just for aviation will require 3 million hectares of algae farms.
Thursday 1 October 2009
At last someone sensible in a position of "power"
Today I read an article on the BBC website that increased my optimism that the UK government may start to take some meaningful steps towards energy management. It's a report of comments by the new Chief Energy Scientist...none other than Professor David MacKay. For those that haven't read earlier blogs, he is the guy who wrote the book "Sustainable Energy Without the Hot Air" - free copies available for download from www.withouthotair.com - or buy it from Amazon.
It turns out he starts his new job today, working for the DECC - Department of Energy and Climate Change.
Why do I think this is good news? Well to put it simply he does the sums and cuts through the crap that gets peddled by the ill informed. If the government actually listen to him and allow him to guide the formation of policy, then it's possible that the changes necessary to get us off our fossil fuel habit may actually get made.
MacKay seems to accept the man-made greenhouse gas emission causing climate change argument - he points out that the sources and sinks are out of balance - although he accepts that it's not a firm conclusion on the available evidence. I remain more of a sceptic, but I am convinced that consuming all the fossil fuels in such a short time span is a very bad idea - so controlling greenhouse gas emissions as a means to an end is a reasonable idea - even though it may lead to some less than ideal policies.
I hope MacKay can inject some of his enthusiasm and a real sense of urgency into the DECC - and act as a real mover and shaker for doing what is necessary and overcoming what appears to be our nation (and world) wide head in the sand approach to energy generation and consumption.
It turns out he starts his new job today, working for the DECC - Department of Energy and Climate Change.
Why do I think this is good news? Well to put it simply he does the sums and cuts through the crap that gets peddled by the ill informed. If the government actually listen to him and allow him to guide the formation of policy, then it's possible that the changes necessary to get us off our fossil fuel habit may actually get made.
MacKay seems to accept the man-made greenhouse gas emission causing climate change argument - he points out that the sources and sinks are out of balance - although he accepts that it's not a firm conclusion on the available evidence. I remain more of a sceptic, but I am convinced that consuming all the fossil fuels in such a short time span is a very bad idea - so controlling greenhouse gas emissions as a means to an end is a reasonable idea - even though it may lead to some less than ideal policies.
I hope MacKay can inject some of his enthusiasm and a real sense of urgency into the DECC - and act as a real mover and shaker for doing what is necessary and overcoming what appears to be our nation (and world) wide head in the sand approach to energy generation and consumption.
Saturday 19 September 2009
Carbon, carbon everywhere...is trading a means to an end?
Much has been made about carbon trading as a means of reducing CO2 emissions recently, but what is it and how does it help?
I have read a few articles about carbon trading, this one by Australian economics correspondent Peter Martin is a fairly clear explanation of the theory and the ideas behind it.
There are many more articles on the web, but a lot of them seem to require a good grounding in the financial jargon and technology that goes along with futures and derivatives markets. As with so many ideas and principles involving governments and economists, once the financial markets get involved there seem to be a large number of people looking to get rich by distorting the original scheme beyond recognition. Much of the recent credit crunch and near collapse of the banking system is due to exactly such behaviours.
The theory is that the best way to promote change is to put a framework in place and then let the free market go to work on it. The problem with this approach is that establishing such a framework that is robust and not subject to distortion caused by the ingenuity of those seeking ever more involved ways of making money is extremely difficult. It is at this point that governments tend to abdicate their responsibilities. Governments trying to explain such complexity to their constituents are up against it - many of the members of the government don't understand it in sufficient detail themselves.
Another problem with such an approach is verifying the basis on which carbon emissions are verified. You can't see CO2, so measuring how much any individual enterprise is emitting relies on measuring their energy usage and calculating the equivalant amount of CO2 produced. Then one has to figure out how much of that energy came from fossil fuels versus renewable sources. As I'm sure most people are aware, even if we wanted to buy our energy entirely from renewable resources today there isn't nearly enough to go around.
It's all very well selling permits, but how do you know whether the system is being operated properly. Wherever money is involved there will always be those willing to play fast and loose with the rules. Regulating such a system globally seems nigh on impossible to me. One non-profit organisation that is participating in the market by offering a certification scheme is The Gold Standard, based in Switzerland. I don't yet understand how they are accredited to do this work - other than acting as a neutral 3rd party with a collaborating set of participants.
The CO2 emissions control is driven by the theory that such emissions are contributing to climate change. This may or may not be true, but if nothing else it helps drive the move away from finite resources of fossil fuels towards more sustainable sources of energy. That has to be a good thing, but how do we determine what are acceptable levels of CO2 emissions? This is an arbitrary number plucked out the air. How do we determine who is allowed to emit how much? Who issues the permits? How do we monitor and control the market? Who plays the role of central authority? Who do we entrust with the role of verification? What happens if someone goes into carbon debt and then goes bust before they've bought new permits? These are a set of very complex problems, with the solutions open to abuse and obfuscation. What happens if we later determine that we need to reduce CO2 emission further? Do existing permits have a lifetime attached to them?
Personally I think this scheme will prove to be unworkable - but that won't stop a lot of people spending a lot of time and money trying - and a few people getting very rich along the way through the usual market speculation.
I have read a few articles about carbon trading, this one by Australian economics correspondent Peter Martin is a fairly clear explanation of the theory and the ideas behind it.
There are many more articles on the web, but a lot of them seem to require a good grounding in the financial jargon and technology that goes along with futures and derivatives markets. As with so many ideas and principles involving governments and economists, once the financial markets get involved there seem to be a large number of people looking to get rich by distorting the original scheme beyond recognition. Much of the recent credit crunch and near collapse of the banking system is due to exactly such behaviours.
The theory is that the best way to promote change is to put a framework in place and then let the free market go to work on it. The problem with this approach is that establishing such a framework that is robust and not subject to distortion caused by the ingenuity of those seeking ever more involved ways of making money is extremely difficult. It is at this point that governments tend to abdicate their responsibilities. Governments trying to explain such complexity to their constituents are up against it - many of the members of the government don't understand it in sufficient detail themselves.
Another problem with such an approach is verifying the basis on which carbon emissions are verified. You can't see CO2, so measuring how much any individual enterprise is emitting relies on measuring their energy usage and calculating the equivalant amount of CO2 produced. Then one has to figure out how much of that energy came from fossil fuels versus renewable sources. As I'm sure most people are aware, even if we wanted to buy our energy entirely from renewable resources today there isn't nearly enough to go around.
It's all very well selling permits, but how do you know whether the system is being operated properly. Wherever money is involved there will always be those willing to play fast and loose with the rules. Regulating such a system globally seems nigh on impossible to me. One non-profit organisation that is participating in the market by offering a certification scheme is The Gold Standard, based in Switzerland. I don't yet understand how they are accredited to do this work - other than acting as a neutral 3rd party with a collaborating set of participants.
The CO2 emissions control is driven by the theory that such emissions are contributing to climate change. This may or may not be true, but if nothing else it helps drive the move away from finite resources of fossil fuels towards more sustainable sources of energy. That has to be a good thing, but how do we determine what are acceptable levels of CO2 emissions? This is an arbitrary number plucked out the air. How do we determine who is allowed to emit how much? Who issues the permits? How do we monitor and control the market? Who plays the role of central authority? Who do we entrust with the role of verification? What happens if someone goes into carbon debt and then goes bust before they've bought new permits? These are a set of very complex problems, with the solutions open to abuse and obfuscation. What happens if we later determine that we need to reduce CO2 emission further? Do existing permits have a lifetime attached to them?
Personally I think this scheme will prove to be unworkable - but that won't stop a lot of people spending a lot of time and money trying - and a few people getting very rich along the way through the usual market speculation.
Monday 14 September 2009
Monitoring Electricity Usage - Real Time
I had been hankering after a real time electricity monitor for a while - these devices basically have a sensor that goes around the electricity cable that feeds into your consumer unit or fuse box (after your meter), with a transmitter attached that sends a signal to a separate display unit. Some units also allow you to hook them up to a PC so's you can download historical data and draw fancy graphs.
Since it was my birthday recently I decided to spend some money I was given as a present on such a unit. The cost of these things is typically 40 to 50 pounds for something pretty fully featured. I was torn between two different devices - the CC 128 made by Current Cost and the Efergy E2. I finally swung in favour of the CC 128 because I was able to get a slightly cheaper second hand one from an Amazon reseller. The disadvantage of this unit is that it needs a special data cable which is sold separately for about 8 pounds - and it also doesn't have any software out the box, although a few people have been developing such.
On the plus side it has a much longer history available (once you can connect it to your computer) and it also has multiple channels, so as well as monitoring the power coming into the house, it's possible to monitor individual applicances using the yet to be released IAM (Individual Appliance Module) sockets.
I received the unit today - interestingly it was badged with British Gas - they must be OEM'ing them. The previous user had used it for 3 days - so the transmitter and receiver were already paired. A quick read of the brochure showed how to set the time and electricity cost - which was pretty straightforward, although far from intuitive. I spent the next few minutes playing with switching things on and off - my computer monitor consumes over 100 Watts for example - to see the effect. Great fun.
My next step was to investigate software. The CC128 outputs XML - and there are different versions of it depending on which version of the device you have. My hope of just finding a bit of freeware and downloading it were shortlived. I did manage to find a suitable generic USB driver which was a start, but my attempts to get any of the other bits of software going have (so far) failed miserably.
Hmmm...fortunately a guy called Dale Lane has done a lot of messing about already with Python scripts and has made their source available - so if I can get the PC talking to the device using some of his code then I may use it as an excuse to learn some Python and do some hacking of my own. I think the Efergy device would have won out here as it comes packaged with a USB cable and ready to use software.
As an aside, there's pretty good information on the whole country's electricity real time usage on the National Grid Website.
Since it was my birthday recently I decided to spend some money I was given as a present on such a unit. The cost of these things is typically 40 to 50 pounds for something pretty fully featured. I was torn between two different devices - the CC 128 made by Current Cost and the Efergy E2. I finally swung in favour of the CC 128 because I was able to get a slightly cheaper second hand one from an Amazon reseller. The disadvantage of this unit is that it needs a special data cable which is sold separately for about 8 pounds - and it also doesn't have any software out the box, although a few people have been developing such.
On the plus side it has a much longer history available (once you can connect it to your computer) and it also has multiple channels, so as well as monitoring the power coming into the house, it's possible to monitor individual applicances using the yet to be released IAM (Individual Appliance Module) sockets.
I received the unit today - interestingly it was badged with British Gas - they must be OEM'ing them. The previous user had used it for 3 days - so the transmitter and receiver were already paired. A quick read of the brochure showed how to set the time and electricity cost - which was pretty straightforward, although far from intuitive. I spent the next few minutes playing with switching things on and off - my computer monitor consumes over 100 Watts for example - to see the effect. Great fun.
My next step was to investigate software. The CC128 outputs XML - and there are different versions of it depending on which version of the device you have. My hope of just finding a bit of freeware and downloading it were shortlived. I did manage to find a suitable generic USB driver which was a start, but my attempts to get any of the other bits of software going have (so far) failed miserably.
Hmmm...fortunately a guy called Dale Lane has done a lot of messing about already with Python scripts and has made their source available - so if I can get the PC talking to the device using some of his code then I may use it as an excuse to learn some Python and do some hacking of my own. I think the Efergy device would have won out here as it comes packaged with a USB cable and ready to use software.
As an aside, there's pretty good information on the whole country's electricity real time usage on the National Grid Website.
Saturday 12 September 2009
Floating windmills - and some defunct ones
Mixed news on the BBC this week - the rather sad story of the demise of a home wind turbine maker in Glasgow, Windsave, was reported here. As I reported in a previous blog entry, for most people, home wind turbines really don't make sense. Most of us simply don't get enough steady wind to get enough power out of these mini turbines to make a sensible difference. Their website has now been taken down, but apparently there was a statement on it acknowledging the disappointing results from the technology.
I sent an email enquiry to a local wind turbine company asking them if they had a table of wind speed versus power output, but so far I've had no reply. It seems odd to me that you'd try and sell such things if you didn't have good data on their likely performance.
On a slightly more upbeat, but rather longer term note, a Norwegian engineer has developed a floating offshore wind turbine. This uses a slack mooring system - similar to Pelamis I guess? - to moor a turbine in relatively deep water. It's about 100 metres below the surface and about the same above - weighed down with rocks as ballast. The benefit this brings is being able to deploy wind turbines in deeper water than can be managed just now, although at present the cost remains a bit high. The report can be read here. I wonder what Don Quixote would have made of such things?
I sent an email enquiry to a local wind turbine company asking them if they had a table of wind speed versus power output, but so far I've had no reply. It seems odd to me that you'd try and sell such things if you didn't have good data on their likely performance.
On a slightly more upbeat, but rather longer term note, a Norwegian engineer has developed a floating offshore wind turbine. This uses a slack mooring system - similar to Pelamis I guess? - to moor a turbine in relatively deep water. It's about 100 metres below the surface and about the same above - weighed down with rocks as ballast. The benefit this brings is being able to deploy wind turbines in deeper water than can be managed just now, although at present the cost remains a bit high. The report can be read here. I wonder what Don Quixote would have made of such things?
Wednesday 9 September 2009
Who Killed the Electric Car?
I referred to this documentary in an earlier blog. I was intrigued enough to order the DVD from Amazon and I watched it with my son earlier this evening. I said in the earlier entry that I'm always a bit wary of eco documentaries - they tend to be very selective and it's hard to know how balanced they are. Taking those caveats into account, I was pretty impressed with this film. In fact everyone should watch this and form their own opinions :-). There's a more full account of the film and all it's players on Wikipedia here.
Of course the story is complicated and there's no single culprit - but my earlier comment on lack of sympathy for GM and others today stands. The destruction of vehicles that people wanted to buy was criminal. Toyota also destroyed vehicles - making their current claim to green credentials somewhat suspect.
The documentary looks at the various players and their motives. It also focuses heavily on those who leased the EV-1 - but were refused the possibility of renewing those leases. Another character who appears is Stanford Ovshinsky, the inventor of the Nickel Metal Hydride battery. The initial GM vehicles used lead acid batteries and had problems. GM bought Ovshinky's company but took 2 years to incorporate the NimH batteries into their vehicles. Perhaps that's how long it took - but they subsequently sold their stake.
Among those named as guilty are the car companies, the oil industry, the US government, the California Air Resource Board (CARB) and the consumer.
Another disturbing thing I learned from the film was that Reagan removed the solar cells that had been installed in the White House by Jimmy Carter. Why? What was the point of that? It might have been one thing never to install them, but to remove them was just a political stunt.
The decision by the CARB to pursue hydrogen fuel cells is also questioned - apparently Alan Lloyd the CARB chairman at the time had joined the California Fuel Cell Partnership - an obvious conflict of interests.
I was also struck by the guys responsible for servicing the electric vehicles - the battery issues aside, they didn't need new oil filters, never wore their brakes out and of course didn't need new exhausts. In other words all the dirty bits associated with internal combustion engines don't exist - and more to the point, the huge spares and maintenance industry that goes with today's cars is greatly reduced.
I can't really do this documentary justice - I suggest watching the film or failing that read the Wikipedia entry and form your own conclusions. There are also a few extras on the DVD, including some deleted scenes.
One thing I do intend to do as a result of watching this is to get a hold of Joseph Romm's book, The Hype About Hydrogen.
Of course the story is complicated and there's no single culprit - but my earlier comment on lack of sympathy for GM and others today stands. The destruction of vehicles that people wanted to buy was criminal. Toyota also destroyed vehicles - making their current claim to green credentials somewhat suspect.
The documentary looks at the various players and their motives. It also focuses heavily on those who leased the EV-1 - but were refused the possibility of renewing those leases. Another character who appears is Stanford Ovshinsky, the inventor of the Nickel Metal Hydride battery. The initial GM vehicles used lead acid batteries and had problems. GM bought Ovshinky's company but took 2 years to incorporate the NimH batteries into their vehicles. Perhaps that's how long it took - but they subsequently sold their stake.
Among those named as guilty are the car companies, the oil industry, the US government, the California Air Resource Board (CARB) and the consumer.
Another disturbing thing I learned from the film was that Reagan removed the solar cells that had been installed in the White House by Jimmy Carter. Why? What was the point of that? It might have been one thing never to install them, but to remove them was just a political stunt.
The decision by the CARB to pursue hydrogen fuel cells is also questioned - apparently Alan Lloyd the CARB chairman at the time had joined the California Fuel Cell Partnership - an obvious conflict of interests.
I was also struck by the guys responsible for servicing the electric vehicles - the battery issues aside, they didn't need new oil filters, never wore their brakes out and of course didn't need new exhausts. In other words all the dirty bits associated with internal combustion engines don't exist - and more to the point, the huge spares and maintenance industry that goes with today's cars is greatly reduced.
I can't really do this documentary justice - I suggest watching the film or failing that read the Wikipedia entry and form your own conclusions. There are also a few extras on the DVD, including some deleted scenes.
One thing I do intend to do as a result of watching this is to get a hold of Joseph Romm's book, The Hype About Hydrogen.
Tuesday 8 September 2009
Storing energy for rainy days
One of the problems with renewable energy is that for wind, wave and solar power the supply is not constant or predictable on a day to day basis. Statistically we can figure out what we're likely to get from any one site based on observation over a period of time and extrapolating that into the future, but we can't predict accurately a long time in advance (i.e. more than a few days based on weather forecasts) how many kW will be available.
Unless we want to build huge amounts of extra capacity, then we need to consider the problem of storing energy for when we need it - in the case of solar power, literally putting something away for a rainy day.
This takes me back to my school days when we were learning about converting energy from one form to another. For example converting electrical to chemical energy in batteries and converting between kinetic (movement) energy and potential energy by raising things up hills and letting them run down again.
What are the options? More to the point, what are practical solutions?
Batteries are plainly useful - but to store the amounts of power we would need to cover for cloudy days with no wind will take a lot of them. One of the solutions being touted is what is known as V2G - vehicle to grid. The theory is that we hook all our electric cars up to the grid to charge - but in such a way that the grid can take electricity from all the plugged in cars when demand is high or supply is low. That will require the kind of smart grid I talked about in a previous blog entry. There are a few practical problems to overcome with this as well. Batteries that are designed for powering cars may not be the best kind of battery for retrieving electricity from rapidly. Then there's the problem of being able to rely on one's vehicle. If you plug it in at night you expect it to be ready to drive in the morning - but if the grid has emptied the battery of all its charge then you won't be going anywhere quickly.
Another option is hydro electricity. Hydro power stations already use off peak electricity that would otherwise be wasted to pump water back up the hill so's it can be used again. There is obviously a net energy loss due to inefficiency, but it's still a pretty good solution. In that sense our hydro power stations are already primarily storage units. It is however very questionable as to whether we can have enough hydro power on tap to meet all our storage needs.
Given that we will likely be challenged to construct enough storage facility to cope with all the lulls and increases in demand in cold weather or when Scotland are about to win the world cup and everyone has their tv's on we need to look at alternatives. For example, it is unlikely that the whole world will be becalmed at any one moment - so trading arrangements supported by HVDC lines for moving electricity between and around countries would seem to be a sensible way to go. The only down side perhaps is that we would be at the mercy of another country in maintaining our electricity supply - but if you consider that we are already pretty much in that state for oil and gas then we'd be no worse off - and perhaps if we have enough renewables, in times of plenty the boot would be on the other foot.
Unless we want to build huge amounts of extra capacity, then we need to consider the problem of storing energy for when we need it - in the case of solar power, literally putting something away for a rainy day.
This takes me back to my school days when we were learning about converting energy from one form to another. For example converting electrical to chemical energy in batteries and converting between kinetic (movement) energy and potential energy by raising things up hills and letting them run down again.
What are the options? More to the point, what are practical solutions?
Batteries are plainly useful - but to store the amounts of power we would need to cover for cloudy days with no wind will take a lot of them. One of the solutions being touted is what is known as V2G - vehicle to grid. The theory is that we hook all our electric cars up to the grid to charge - but in such a way that the grid can take electricity from all the plugged in cars when demand is high or supply is low. That will require the kind of smart grid I talked about in a previous blog entry. There are a few practical problems to overcome with this as well. Batteries that are designed for powering cars may not be the best kind of battery for retrieving electricity from rapidly. Then there's the problem of being able to rely on one's vehicle. If you plug it in at night you expect it to be ready to drive in the morning - but if the grid has emptied the battery of all its charge then you won't be going anywhere quickly.
Another option is hydro electricity. Hydro power stations already use off peak electricity that would otherwise be wasted to pump water back up the hill so's it can be used again. There is obviously a net energy loss due to inefficiency, but it's still a pretty good solution. In that sense our hydro power stations are already primarily storage units. It is however very questionable as to whether we can have enough hydro power on tap to meet all our storage needs.
Given that we will likely be challenged to construct enough storage facility to cope with all the lulls and increases in demand in cold weather or when Scotland are about to win the world cup and everyone has their tv's on we need to look at alternatives. For example, it is unlikely that the whole world will be becalmed at any one moment - so trading arrangements supported by HVDC lines for moving electricity between and around countries would seem to be a sensible way to go. The only down side perhaps is that we would be at the mercy of another country in maintaining our electricity supply - but if you consider that we are already pretty much in that state for oil and gas then we'd be no worse off - and perhaps if we have enough renewables, in times of plenty the boot would be on the other foot.
Monday 7 September 2009
No Fossils in MY house...part 3 - Solar Photo-Voltaic cells
Solar power can either be used to heat something up, or in the case of Photo-Voltaic or PV cells, generate electricity directly. These are devices, usually made of silicon, that respond to sunlight by producing electricity. They are rated in kWp, which is kilowatts peak - the amount of electrical power they produce in direct sunlight.
Putting PV cells on the roof to generate electricity sounds like quite a neat idea. We could easily angle them to face south. In Edinburgh the average incident solar energy that falls is about 100 watts per square metre. PV cell efficiency is a bit of a challenge however. There is a theoretical limit to the efficiency of solar cells due to something called the band-gap problem of about 50%, however the best today are about 20% and typical ones are about 10% efficient.
The other slight problem is that last time I looked, the sun doesn't shine at night, so that suggests that one needs to charge batteries for overnight power. The other slight problem is that in the winter when the daylight hours are shortest is when demand for electricity tends to be highest. The battery problem can be overcome in a sense if one is "grid connected". The theory is that one generates excess electricity during the day and sells it to the grid - effectively using it as a storage system - and then buys it back during the night or during periods of insufficient generation. Of course, this assumes that someone somewhere has spare capacity when you need it during the night - not an unreasonable assumption.
As well as the PV cells, one needs an inverter to convert the DC from the cells/storage battery in to AC.
On the plus side, solar cells should be relatively cheap at the moment due to overcapacity in manufacturing. This article describes the problem. That might explain why Maplin had a sale on a while ago for solar products.
As well as the cells and a set of batteries to charge, you also need an inverter to turn the electricity from DC to AC. I haven't investigated this completely - but I am assuming that devices are available that will allow one to become grid connected - basically as well as generating AC, it needs to match the phase and frequency of your generator to your local supply. The Distribution Network Operators have different policies when it comes to connecting one's generation system to the grid. Again I haven't investigated the details of this yet either.
A quick survey suggests that a 120W cell will work out at about 600 pounds, plus batteries, charge controller and inverter. I'm guessing we would need 3 or 4 such devices to allow for not having full sunlight all the time to achieve 120 watts - let's say 4 for luck. I would need to do some more figuring to determine how many watts we should aim to generate and store - but let's assume we want to generate our full 7500 kWh per year.
Assuming an average10 hours daylight per day - which is probably a bit optimistic, and 4 cells generating 120W (let's call it 100 for the sake of round numbers) for 10 hours would generate 1 kWh per day. That means we'd need 20 such arrays (hmmm...my roof will be a bit full with that lot on it,) - or maybe 80 cells at the cost of about 600 pounds each. That's not far off fifty thousand quid! The cost of the other bits disappears into the noise! Payback time? Given that one of the cells is about the same as our annual electricity bill, it's going to be about 80 years.
This doesn't look like a very good plan either. Maybe solar cells will get a lot cheaper and maybe my estimates of the number needed are a bit awry - but the payback period still looks to be pretty long.
Putting PV cells on the roof to generate electricity sounds like quite a neat idea. We could easily angle them to face south. In Edinburgh the average incident solar energy that falls is about 100 watts per square metre. PV cell efficiency is a bit of a challenge however. There is a theoretical limit to the efficiency of solar cells due to something called the band-gap problem of about 50%, however the best today are about 20% and typical ones are about 10% efficient.
The other slight problem is that last time I looked, the sun doesn't shine at night, so that suggests that one needs to charge batteries for overnight power. The other slight problem is that in the winter when the daylight hours are shortest is when demand for electricity tends to be highest. The battery problem can be overcome in a sense if one is "grid connected". The theory is that one generates excess electricity during the day and sells it to the grid - effectively using it as a storage system - and then buys it back during the night or during periods of insufficient generation. Of course, this assumes that someone somewhere has spare capacity when you need it during the night - not an unreasonable assumption.
As well as the PV cells, one needs an inverter to convert the DC from the cells/storage battery in to AC.
On the plus side, solar cells should be relatively cheap at the moment due to overcapacity in manufacturing. This article describes the problem. That might explain why Maplin had a sale on a while ago for solar products.
As well as the cells and a set of batteries to charge, you also need an inverter to turn the electricity from DC to AC. I haven't investigated this completely - but I am assuming that devices are available that will allow one to become grid connected - basically as well as generating AC, it needs to match the phase and frequency of your generator to your local supply. The Distribution Network Operators have different policies when it comes to connecting one's generation system to the grid. Again I haven't investigated the details of this yet either.
A quick survey suggests that a 120W cell will work out at about 600 pounds, plus batteries, charge controller and inverter. I'm guessing we would need 3 or 4 such devices to allow for not having full sunlight all the time to achieve 120 watts - let's say 4 for luck. I would need to do some more figuring to determine how many watts we should aim to generate and store - but let's assume we want to generate our full 7500 kWh per year.
Assuming an average10 hours daylight per day - which is probably a bit optimistic, and 4 cells generating 120W (let's call it 100 for the sake of round numbers) for 10 hours would generate 1 kWh per day. That means we'd need 20 such arrays (hmmm...my roof will be a bit full with that lot on it,) - or maybe 80 cells at the cost of about 600 pounds each. That's not far off fifty thousand quid! The cost of the other bits disappears into the noise! Payback time? Given that one of the cells is about the same as our annual electricity bill, it's going to be about 80 years.
This doesn't look like a very good plan either. Maybe solar cells will get a lot cheaper and maybe my estimates of the number needed are a bit awry - but the payback period still looks to be pretty long.
Sunday 6 September 2009
No Fossils in MY house...part 2 - wind power
As part of the ongoing research into how we might lessen our dependency on the grid I looked at windpower as a possible option. There might even be a possibility of selling any excess electricity back to the grid and becoming part of the micro-renewables community.
There are a few companies that will sell you turbines - A company called Renewable Energy Devices offers Swift Turbines for example. On the face of it these look like nice devices, with an option for battery storage which is probably essential if you're going to get the best out of them. The brochure claims about being quiet and bird and bat safe are impressive.
They estimate that a turbine that is capable of generating 1.5 kW of power will cost about 7000 pounds to buy and install. That can be reduced to the end user if grants are available as they typically are in the UK. It's not clear if that costs includes planning permission. They further suggest that that could generate about 2000 kWh of electricity per year. That's less than a sixth of the theoretical maximum (24 * 1.5 * 365 = 13140 kWh) so may be realistic for a typical UK residential site with minimal obstructions such as up on a roof.
Just for comparison, the biggest industrial wind turbines are now capable of generating 5 Mega Watts - and 2.5 Mega Watts is typical.
Given that we pay just over 10 pence per kWh (and we use about 7500 kWh per year,) it would seem we could reduce our grid electricity usage by about 25% and save 200 pounds a year. That would suggest a payback period of 35 years! Perhaps that could be reduced to 20 years with maximum grants. Their brochure somewhat misleadingly claims that on a good site payback could be as little as 5 years. This can only be achieved if maximum output can be maintained unbroken for that 5 years. (13140 * 5 = 65700 kWh @ 10p per kWh = approximately 6500 pounds.)
One has to dig through the brochure small print to discover that 1.5 kW is from a rated wind speed of 12 metres/second. Unfortunately there is no table available on the site showing the performance under different wind speed conditions. They do claim that it will work in extreme wind conditions - although they don't explain what that means. I happen to have a remote weather station on my roof. I haven't been monitoring it very closely recently, but between October and December 2008 the average wind speed, from snapshots taken every 15 minutes, was 3 metres/second. Even today, which is fairly windy, the average is under 4 metres/second. That seems to fall a long way short of the number needed for efficient generation from this turbine.
Update - 8th September - a very windy day and the average is still only around 8 m/s. Strongest gust was just over 15 metres/second. (1 metre/second = 2.237 mph).
I am therefore lead to conclude that investing in personal wind power at this stage doesn't seem like a good option for our household. A payback time of 5 to 7 years would not seem unreasonable but 35 years strains my sense of credulity.
There are a few companies that will sell you turbines - A company called Renewable Energy Devices offers Swift Turbines for example. On the face of it these look like nice devices, with an option for battery storage which is probably essential if you're going to get the best out of them. The brochure claims about being quiet and bird and bat safe are impressive.
They estimate that a turbine that is capable of generating 1.5 kW of power will cost about 7000 pounds to buy and install. That can be reduced to the end user if grants are available as they typically are in the UK. It's not clear if that costs includes planning permission. They further suggest that that could generate about 2000 kWh of electricity per year. That's less than a sixth of the theoretical maximum (24 * 1.5 * 365 = 13140 kWh) so may be realistic for a typical UK residential site with minimal obstructions such as up on a roof.
Just for comparison, the biggest industrial wind turbines are now capable of generating 5 Mega Watts - and 2.5 Mega Watts is typical.
Given that we pay just over 10 pence per kWh (and we use about 7500 kWh per year,) it would seem we could reduce our grid electricity usage by about 25% and save 200 pounds a year. That would suggest a payback period of 35 years! Perhaps that could be reduced to 20 years with maximum grants. Their brochure somewhat misleadingly claims that on a good site payback could be as little as 5 years. This can only be achieved if maximum output can be maintained unbroken for that 5 years. (13140 * 5 = 65700 kWh @ 10p per kWh = approximately 6500 pounds.)
One has to dig through the brochure small print to discover that 1.5 kW is from a rated wind speed of 12 metres/second. Unfortunately there is no table available on the site showing the performance under different wind speed conditions. They do claim that it will work in extreme wind conditions - although they don't explain what that means. I happen to have a remote weather station on my roof. I haven't been monitoring it very closely recently, but between October and December 2008 the average wind speed, from snapshots taken every 15 minutes, was 3 metres/second. Even today, which is fairly windy, the average is under 4 metres/second. That seems to fall a long way short of the number needed for efficient generation from this turbine.
Update - 8th September - a very windy day and the average is still only around 8 m/s. Strongest gust was just over 15 metres/second. (1 metre/second = 2.237 mph).
I am therefore lead to conclude that investing in personal wind power at this stage doesn't seem like a good option for our household. A payback time of 5 to 7 years would not seem unreasonable but 35 years strains my sense of credulity.
Saturday 5 September 2009
No fossils in MY house...part 1 - heat pumps.
Wouldn't it be great if we could just take ourselves off the electricity and gas grids? Provide our own sources of heat and electricity for running all our gadgets and household objects? Some people have done it, but it's no easy undertaking for the majority of us.
I have looked at some options for our house. We live in a city, in a reasonably large, but old house. We have some flat roof space and we have a reasonably large garden (a bit over a hundred square metres.) It should be possible to do something useful with that.
Given the garden, I was initially attracted to ground source heat pumps. These are brilliant devices that work like fridges running in reverse. They pump heat from the ground into your house using electricity to run the pump to move the refrigerant through a heat exchanger. In hot weather it's possible to run them in reverse to cool the house down and heat the ground up again. You simply bury a long length of pipe in your garden, fill it with "refrigerant" and install a heat exchanger.
The key parameter in a heat pump is something called the coefficient of performance - which is basically the ratio of how much energy you can extract from the ground divided by how much electrical power you need to put into the device to pump. Numbers on the order of 4 or just under are good for a ground source heat pump.
There are however some challenges. To get a good coefficient of performance one needs as small a temperature difference between the ground and the target as possible. The ground temperature in the UK is about 11 degrees centigrade. A target of about 40 degrees centigrade can be achieved at a fairly good coefficient of performance. As you try to raise the temperature higher the coefficient of performance falls - and you also risk over cooling the ground unless you have a large enough capture area.
To get good use from such pumps therefore requires very good insulation and ideally switching from radiators to underfloor heating. That pretty much blows away the idea for our house and indeed for anyone who isn't moving into a house built under the newest regulations for insulation. We could just about rip up the floors to install underfloor heating - no easy undertaking - but the insulation problem is I'm afraid insurmountable.
There is a very useful site for anyone interested in such devices here. I originally looked at the Iceenergy site - I am not endorsing their products - although plenty of high profile names are, including Claire Short, however it looks like a good place to start. That said, they provide a product and some engineering, but you're expected to do quite a bit of the work towards an installation yourself.
If one doesn't have space for a ground source heat pump one could always go for an air source pump. The principle is exactly the same - except the energy to heat the house comes from the outside air. There are some obvious benefits since you don't need a garden to dig up. Coefficients of performance as high as 6 can be achieved. You still have the challenge of insulation to deal with - and you are more at the mercy of the outside temperature. Whereas the ground temperature is fairly constant, air temperature varies - depending on where you live by perhaps a large amount. The colder it is the higher the difference in temperature likely being desired and the less efficient the heat pump will be.
Of course, heat alone isn't enough - you need electricity to run the pumps. More on that in a future blog...
I have looked at some options for our house. We live in a city, in a reasonably large, but old house. We have some flat roof space and we have a reasonably large garden (a bit over a hundred square metres.) It should be possible to do something useful with that.
Given the garden, I was initially attracted to ground source heat pumps. These are brilliant devices that work like fridges running in reverse. They pump heat from the ground into your house using electricity to run the pump to move the refrigerant through a heat exchanger. In hot weather it's possible to run them in reverse to cool the house down and heat the ground up again. You simply bury a long length of pipe in your garden, fill it with "refrigerant" and install a heat exchanger.
The key parameter in a heat pump is something called the coefficient of performance - which is basically the ratio of how much energy you can extract from the ground divided by how much electrical power you need to put into the device to pump. Numbers on the order of 4 or just under are good for a ground source heat pump.
There are however some challenges. To get a good coefficient of performance one needs as small a temperature difference between the ground and the target as possible. The ground temperature in the UK is about 11 degrees centigrade. A target of about 40 degrees centigrade can be achieved at a fairly good coefficient of performance. As you try to raise the temperature higher the coefficient of performance falls - and you also risk over cooling the ground unless you have a large enough capture area.
To get good use from such pumps therefore requires very good insulation and ideally switching from radiators to underfloor heating. That pretty much blows away the idea for our house and indeed for anyone who isn't moving into a house built under the newest regulations for insulation. We could just about rip up the floors to install underfloor heating - no easy undertaking - but the insulation problem is I'm afraid insurmountable.
There is a very useful site for anyone interested in such devices here. I originally looked at the Iceenergy site - I am not endorsing their products - although plenty of high profile names are, including Claire Short, however it looks like a good place to start. That said, they provide a product and some engineering, but you're expected to do quite a bit of the work towards an installation yourself.
If one doesn't have space for a ground source heat pump one could always go for an air source pump. The principle is exactly the same - except the energy to heat the house comes from the outside air. There are some obvious benefits since you don't need a garden to dig up. Coefficients of performance as high as 6 can be achieved. You still have the challenge of insulation to deal with - and you are more at the mercy of the outside temperature. Whereas the ground temperature is fairly constant, air temperature varies - depending on where you live by perhaps a large amount. The colder it is the higher the difference in temperature likely being desired and the less efficient the heat pump will be.
Of course, heat alone isn't enough - you need electricity to run the pumps. More on that in a future blog...
Friday 4 September 2009
Electric cars - the way to go
Cars are to me a very visible reminder of our incredible consumption of fossil fuels in the form of oil. Of course, oil gets refined into different grades of which petroleum and diesel are just two.
When one stands over a motorway or observes traffic in a city, one can hardly fail to be struck by the sheer volume of cars and lorries and the amount of fuel they are burning their way through. When they're stuck going nowhere because of congestion the fuel isn't even being used to move them - it's just heating the atmosphere. The oil industry has gotten very efficient at distributing fuel - and cars have gotten good at going reasonably long distances between refills. There are however an awful lot of cars out there.
There have been previous experiments in electric cars. GM's impact car of 1990 was a very promising looking prototype. There's a GM video on this site showing the early vehicle - and it's very impressive. Twenty years on and there are almost no electric vehicles on the road. What happened? There's a film, made in 2006, called "Who Killed the Electric Car?". You can watch a trailer here. Being a little wary of any films that have a political axe to grind in terms of their balance (particularly eco films), it still seems incredible that GM killed off their electric vehicles in 1999. As a result I have little sympathy for the problems they now find themselves in as a result of the credit crunch. (Now I'm getting political :-)).
Sinclair's C5 was rather less successful - a good idea but not well enough executed. Sinclair did however show vision, as he had done before with watches, calculators and personal computers.
It seems that the time is right for a resurgence in electric vehicles. Gordon Brown, the British Prime Minister recently announced just before the April 2009 budget that the UK would move to electric vehicles - although I haven't seen much follow up on this yet.
There are plenty of well documented challenges with moving to electric vehicles. Battery technology being one, support infrastructure for recharging being another. If you are unfortunate enough to run out of fuel in a combustion engined car then it is usually possible to carry a gallon or two of fuel from a fuel station to the stranded vehicle. If you run out of electric power then your options are rather more limited - perhaps a solar cell on the roof would eventually give you enough charge to move again - that could require many hours of daylight - so don't run out in the dark!
Just plugging in to recharge may be ok for people who use their car for commuting relatively short distances or nipping to the shops - but it isn't likely to work for people travelling longer distances or who live in remote rural areas.
I saw a video somewhere (if I can find it again I'll post a link) showing a conceptual battery replacement station where the car drives in and the battery is replaced automatically in about 2 or 3 minutes. No longer than it takes to fill a car at a pump today. How many such stations would be needed across the UK? How far apart could they be? How do you ensure that there are enough replacement batteries available at any one station? How do you ensure enough standardisation of batteries to ensure compatibility? How do you maintain the quality of the batteries? How long would they take to recharge? How would you pay? Who would own the stations? What do you do with the batteries at the end of their life? There are a lot of practical questions to be answered here. Whatever the answers there needs to be a practical business model.
It has been pointed out that electric vehicles are charged with electricity from the grid which is generated from fossil fuels. This is of course true (although nuclear and renewables will contribute more in the future), but the power stations are far more efficient at burning those fossil fuels than vehicles - perhaps 75% more efficient.
Today the electric cars available for purchase are either very expensive (e.g. the Tesla) and/or of very limited range - suitable for urban use perhaps, but little else. That's not to say they shouldn't be used - they may well suit a very large percentage of the populations' primary vehicle use pattern - but they are not a complete solution.
There are intermediate vehicles becoming available in the form of hybrids such as the Toyota Prius - but they are pretty expensive and effectively only increase the miles per gallon of fuel rather than offering a choice of electric or fuel power. (According to the Toyota website, they can cover a mile at 31 mph on electric power only - not even enough for the school run.)
All that said, it seems to me that electric vehicles offer great promise, even if initially only in urban environments where the infrastructure to support them can be more easily deployed.
We just need to make sure that nobody kills the electric car again!
When one stands over a motorway or observes traffic in a city, one can hardly fail to be struck by the sheer volume of cars and lorries and the amount of fuel they are burning their way through. When they're stuck going nowhere because of congestion the fuel isn't even being used to move them - it's just heating the atmosphere. The oil industry has gotten very efficient at distributing fuel - and cars have gotten good at going reasonably long distances between refills. There are however an awful lot of cars out there.
There have been previous experiments in electric cars. GM's impact car of 1990 was a very promising looking prototype. There's a GM video on this site showing the early vehicle - and it's very impressive. Twenty years on and there are almost no electric vehicles on the road. What happened? There's a film, made in 2006, called "Who Killed the Electric Car?". You can watch a trailer here. Being a little wary of any films that have a political axe to grind in terms of their balance (particularly eco films), it still seems incredible that GM killed off their electric vehicles in 1999. As a result I have little sympathy for the problems they now find themselves in as a result of the credit crunch. (Now I'm getting political :-)).
Sinclair's C5 was rather less successful - a good idea but not well enough executed. Sinclair did however show vision, as he had done before with watches, calculators and personal computers.
It seems that the time is right for a resurgence in electric vehicles. Gordon Brown, the British Prime Minister recently announced just before the April 2009 budget that the UK would move to electric vehicles - although I haven't seen much follow up on this yet.
There are plenty of well documented challenges with moving to electric vehicles. Battery technology being one, support infrastructure for recharging being another. If you are unfortunate enough to run out of fuel in a combustion engined car then it is usually possible to carry a gallon or two of fuel from a fuel station to the stranded vehicle. If you run out of electric power then your options are rather more limited - perhaps a solar cell on the roof would eventually give you enough charge to move again - that could require many hours of daylight - so don't run out in the dark!
Just plugging in to recharge may be ok for people who use their car for commuting relatively short distances or nipping to the shops - but it isn't likely to work for people travelling longer distances or who live in remote rural areas.
I saw a video somewhere (if I can find it again I'll post a link) showing a conceptual battery replacement station where the car drives in and the battery is replaced automatically in about 2 or 3 minutes. No longer than it takes to fill a car at a pump today. How many such stations would be needed across the UK? How far apart could they be? How do you ensure that there are enough replacement batteries available at any one station? How do you ensure enough standardisation of batteries to ensure compatibility? How do you maintain the quality of the batteries? How long would they take to recharge? How would you pay? Who would own the stations? What do you do with the batteries at the end of their life? There are a lot of practical questions to be answered here. Whatever the answers there needs to be a practical business model.
It has been pointed out that electric vehicles are charged with electricity from the grid which is generated from fossil fuels. This is of course true (although nuclear and renewables will contribute more in the future), but the power stations are far more efficient at burning those fossil fuels than vehicles - perhaps 75% more efficient.
Today the electric cars available for purchase are either very expensive (e.g. the Tesla) and/or of very limited range - suitable for urban use perhaps, but little else. That's not to say they shouldn't be used - they may well suit a very large percentage of the populations' primary vehicle use pattern - but they are not a complete solution.
There are intermediate vehicles becoming available in the form of hybrids such as the Toyota Prius - but they are pretty expensive and effectively only increase the miles per gallon of fuel rather than offering a choice of electric or fuel power. (According to the Toyota website, they can cover a mile at 31 mph on electric power only - not even enough for the school run.)
All that said, it seems to me that electric vehicles offer great promise, even if initially only in urban environments where the infrastructure to support them can be more easily deployed.
We just need to make sure that nobody kills the electric car again!
Thursday 3 September 2009
Light Bulbs and Oil Wells
There have been a couple of energy related happenings in the last few days.
EU legislation banning the sale of 100 watt incandescent light bulbs for domestic use came into force and BP announced a huge oil find in the Gulf of Mexico.
There has been much wailing and gnashing of teeth over the light bulb ban in the UK. The complaints are over different aspects of the alternative energy saving bulbs - known as compact fluorescent lamps or CFL's. These use about a quarter of the amount of energy for the same level of light output - in other words they are more efficient. There are a few issues with them. They put out a different spectrum of light compared to tungsten filament incandescent bulbs - which many people complain is colder than the light they're used to. They also contain small amounts of mercury meaning that the disposal of the bulbs needs to be managed more carefully. Finally they take time to warm up - perhaps as much as a minute before they're up to full intensity.
There are other complaints about the new bulbs - their life is severely reduced by short on-off cycles - it's recommended that they be left on for at least 15 minutes to overcome this effect. Some people complain that they trigger health issues such as migraines. Without doing proper trials - which would be very difficult to do in a true blind (sic) sense - it's impossible to verify such issues, so we are subject to anecdotal reporting.
How much energy can be saved by using these bulbs? According to the article in the above link the European Commission estimate up to 40 Terawatt hours per year. That sounds like a big number - we should do some sums to verify this. Other estimates say up to 7% of domestic electricity. It's important to get a like for like comparison - including the amount of energy used in the manufacture, use and disposal (recycling) of both types of bulb. I haven't managed to find those numbers yet. For the end consumer, if the bulbs last as long as they are advertised then there will be a net saving of a few pounds per light bulb.
As one respondent to the BBC pointed out, in terms of CO2 savings they can catch a jumbo jet to fly to the other side of the world (a return trip to the US in a fully loaded plane will generate about 2 tons of CO2 per person) but they can no longer buy an incandescent light bulb. That doesn't make switching to low energy bulbs wrong - it simply isn't enough to address our current energy addiction.
The BP oil find is I think mixed news. On the one hand, great - we can go on living our current lifestyle for longer. On the other not so great - we will go on living our current lifestyle for longer. This will do little to discourage our continuing consumption of a limited resource.
I hadn't appreciated that typically only 30% of the available oil in a well is extracted - I'd like to learn more about that. This is a deep well and I'd also be curious to know how the cost of extraction will compare with oil elsewhere in the world.
Our political ambivalence towards energy usage needs to be addressed. If we are going to move away from fossil fuels before it's too late to avoid a major energy crisis I personally believe that legislation will be required. For that legislation to be successful and supported by the populace we need to start addressing the problem in a considered manner. That's a hard thing to do when large numbers of people from different walks of life around the world are involved. The human race doesn't have a great record for widespread considered and sensible debate. Self interest and emotion tend to dominate and facts get rapidly lost in the melee.
EU legislation banning the sale of 100 watt incandescent light bulbs for domestic use came into force and BP announced a huge oil find in the Gulf of Mexico.
There has been much wailing and gnashing of teeth over the light bulb ban in the UK. The complaints are over different aspects of the alternative energy saving bulbs - known as compact fluorescent lamps or CFL's. These use about a quarter of the amount of energy for the same level of light output - in other words they are more efficient. There are a few issues with them. They put out a different spectrum of light compared to tungsten filament incandescent bulbs - which many people complain is colder than the light they're used to. They also contain small amounts of mercury meaning that the disposal of the bulbs needs to be managed more carefully. Finally they take time to warm up - perhaps as much as a minute before they're up to full intensity.
There are other complaints about the new bulbs - their life is severely reduced by short on-off cycles - it's recommended that they be left on for at least 15 minutes to overcome this effect. Some people complain that they trigger health issues such as migraines. Without doing proper trials - which would be very difficult to do in a true blind (sic) sense - it's impossible to verify such issues, so we are subject to anecdotal reporting.
How much energy can be saved by using these bulbs? According to the article in the above link the European Commission estimate up to 40 Terawatt hours per year. That sounds like a big number - we should do some sums to verify this. Other estimates say up to 7% of domestic electricity. It's important to get a like for like comparison - including the amount of energy used in the manufacture, use and disposal (recycling) of both types of bulb. I haven't managed to find those numbers yet. For the end consumer, if the bulbs last as long as they are advertised then there will be a net saving of a few pounds per light bulb.
As one respondent to the BBC pointed out, in terms of CO2 savings they can catch a jumbo jet to fly to the other side of the world (a return trip to the US in a fully loaded plane will generate about 2 tons of CO2 per person) but they can no longer buy an incandescent light bulb. That doesn't make switching to low energy bulbs wrong - it simply isn't enough to address our current energy addiction.
The BP oil find is I think mixed news. On the one hand, great - we can go on living our current lifestyle for longer. On the other not so great - we will go on living our current lifestyle for longer. This will do little to discourage our continuing consumption of a limited resource.
I hadn't appreciated that typically only 30% of the available oil in a well is extracted - I'd like to learn more about that. This is a deep well and I'd also be curious to know how the cost of extraction will compare with oil elsewhere in the world.
Our political ambivalence towards energy usage needs to be addressed. If we are going to move away from fossil fuels before it's too late to avoid a major energy crisis I personally believe that legislation will be required. For that legislation to be successful and supported by the populace we need to start addressing the problem in a considered manner. That's a hard thing to do when large numbers of people from different walks of life around the world are involved. The human race doesn't have a great record for widespread considered and sensible debate. Self interest and emotion tend to dominate and facts get rapidly lost in the melee.
Wednesday 2 September 2009
It's windy out there...but is it windy enough?
Much is being made of wind energy as a key renewable resource. The question is whether or not there is enough of it to provide for our needs. Wind is not a constant - even though it might seem like that sometimes! In fact it varies hugely in most places from day to day and week to week. It also varies a great deal from place to place.
Wind farms are springing up in a number of places and lots of companies are busy building them, with plenty more to come. How many windmills will we need? Where can we put them?
There are plenty of impressive sounding 10 or even 100 mega-watt numbers being thrown around for individual wind farm output - but UK energy consumption is in the 10's of giga-watt range. The other problem is that these tend to be peak numbers - you can only achieve that when the wind is blowing within a fairly narrow range of optimum speeds.
Wind energy captured by a turbine is proportional to the area of the blades multiplied by the cube of the wind speed. (Cyclists know this relationship well - the wind resistance goes up cubically as you pedal harder.)
This cubic relationship is one of the things that makes wind farm design a bit tricky. Too much wind and generators and transmission capacity can be overloaded and the turbine blades themselves could be damaged - so over a certain limit the turbines have to be shut down. Too little and the turbines won't even turn. A lot of work has gone into making wind turbines operate across wide ranges of wind speeds - feathering the blades for example - but it is still a challenge. In many ways achieving a predictable output is more important from a practical perspective than achieving the highest possible output.
The industry and the press tend to talk about two sources of wind energy - offshore and onshore, which funnily enough are either in the sea or on land. Mackay's book estimates an average 3 watts per square metre for offshore wind. The main benefit is that the wind is steadier and more consistent and not affected by mountains and trees. The engineering challenges of offshore wind farms are not insignificant, there's a cool marketing video on the RWE website showing the building of the North Hoyle offshore wind farm. This farm will generate a peak of 60 MegaWatts of electricity. Compare that with a typical coal fired power station generating on the order of 1 to 2 GigaWatts - 20 times as much in a much smaller area.
In summary, wind energy is useful - but on it's own it isn't going to be enough to get us off our fossil fuel habit.
David Mackay's estimates for onshore wind energy are an average of 2W/square metre across the UK. To turn that into enough useful energy for the UK will require a lot of wind turbines. With those numbers, even if we covered 10% of the UK land area with wind turbines (not very likely) we would generate only 20 kWh per day per person - a long way short of the 125 kWh per day average that we use today. That might be enough to provide about half of our typical domestic needs.
As with waves, once wind has been used to do work by turning a turbine, it is slowed down and is not then able to be used again.
Wind farms are springing up in a number of places and lots of companies are busy building them, with plenty more to come. How many windmills will we need? Where can we put them?
There are plenty of impressive sounding 10 or even 100 mega-watt numbers being thrown around for individual wind farm output - but UK energy consumption is in the 10's of giga-watt range. The other problem is that these tend to be peak numbers - you can only achieve that when the wind is blowing within a fairly narrow range of optimum speeds.
Wind energy captured by a turbine is proportional to the area of the blades multiplied by the cube of the wind speed. (Cyclists know this relationship well - the wind resistance goes up cubically as you pedal harder.)
This cubic relationship is one of the things that makes wind farm design a bit tricky. Too much wind and generators and transmission capacity can be overloaded and the turbine blades themselves could be damaged - so over a certain limit the turbines have to be shut down. Too little and the turbines won't even turn. A lot of work has gone into making wind turbines operate across wide ranges of wind speeds - feathering the blades for example - but it is still a challenge. In many ways achieving a predictable output is more important from a practical perspective than achieving the highest possible output.
The industry and the press tend to talk about two sources of wind energy - offshore and onshore, which funnily enough are either in the sea or on land. Mackay's book estimates an average 3 watts per square metre for offshore wind. The main benefit is that the wind is steadier and more consistent and not affected by mountains and trees. The engineering challenges of offshore wind farms are not insignificant, there's a cool marketing video on the RWE website showing the building of the North Hoyle offshore wind farm. This farm will generate a peak of 60 MegaWatts of electricity. Compare that with a typical coal fired power station generating on the order of 1 to 2 GigaWatts - 20 times as much in a much smaller area.
In summary, wind energy is useful - but on it's own it isn't going to be enough to get us off our fossil fuel habit.
Tuesday 1 September 2009
Energy from the sea...
There are a couple of ways of getting energy from the sea - tidal energy, which is effectively energy from the moon, since tides are caused by the moon orbiting the earth - and wave energy, which is energy from the sun causing wind which whips up the waves.
The methods for extracting these two types of energy differs. The big benefit of tidal energy is that it's predictable - and constant (in that the tides happen twice a day every day - well almost - although the height of the tide will vary depending on whether the sun and moon are aligned or in opposition or somewhere in between.) I haven't seen much beyond the theory yet on extracting tidal energy - that may be due to my ignorance - but tidal barrages are likely to be big and thus nimbyism and other practical problems are likely to dominate.
Wave energy suffers from the same problems as wind energy in that if the wind drops, then the height of the waves will drop and there will be less energy available. The converse is also true - if the waves get too big then the wave generator could generate too much power, causing electrical damage or be physically damaged. Sea waves are hard to predict - quite a bit of work has been done making practical measurements and then creating mathematical models to allow engineering analysis to be done. These go by names such as Pierson-Moskowitz and JONSWAP. One of the interesting things for me is the similarity between this work and some of the more traditional signal processing that goes on in the telecomms world.
There are a few companies in Scotland working on wave energy.
[2017 update: Since I originally wrote this, the two Edinburgh companies mentioned below have both gone out of business. You can find a history of Pelamis here at https://www.
Two in Edinburgh are Pelamis Wave Power (with their Pelamis device - 50 - 70 metre water depth) and Aquamarine Power (with their Oyster, nearshore 10 - 12 metre water depth.) Another company based in Inverness is Wavegen who have built a prototype onshore wave generator on Islay. These devices each have their own advantages and disadvantages. They each have some interesting videos on their websites that are worth a watch. Both Oyster and Pelamis have been deployed at the European Marine Energy Centre (EMEC) at Orkney.
It would be nice if you could simply line these devices up - Pelamis in the deep water, Oyster in the shallow water and the Wavegen device onshore, but unfortunately it doesn't work like that. Decent size waves require a long "fetch" - and once the energy has been extracted by one of these devices that's it - you can't have the energy twice.
I happened to stop by Pelamis Wave Power this morning whilst out for a bike ride. A couple of their big tubes were visible in the construction shed. I wonder if these are the ones ordered by E.ON?
The methods for extracting these two types of energy differs. The big benefit of tidal energy is that it's predictable - and constant (in that the tides happen twice a day every day - well almost - although the height of the tide will vary depending on whether the sun and moon are aligned or in opposition or somewhere in between.) I haven't seen much beyond the theory yet on extracting tidal energy - that may be due to my ignorance - but tidal barrages are likely to be big and thus nimbyism and other practical problems are likely to dominate.
Wave energy suffers from the same problems as wind energy in that if the wind drops, then the height of the waves will drop and there will be less energy available. The converse is also true - if the waves get too big then the wave generator could generate too much power, causing electrical damage or be physically damaged. Sea waves are hard to predict - quite a bit of work has been done making practical measurements and then creating mathematical models to allow engineering analysis to be done. These go by names such as Pierson-Moskowitz and JONSWAP. One of the interesting things for me is the similarity between this work and some of the more traditional signal processing that goes on in the telecomms world.
There are a few companies in Scotland working on wave energy.
[2017 update: Since I originally wrote this, the two Edinburgh companies mentioned below have both gone out of business. You can find a history of Pelamis here at https://www.
Two in Edinburgh are Pelamis Wave Power (with their Pelamis device - 50 - 70 metre water depth) and Aquamarine Power (with their Oyster, nearshore 10 - 12 metre water depth.) Another company based in Inverness is Wavegen who have built a prototype onshore wave generator on Islay. These devices each have their own advantages and disadvantages. They each have some interesting videos on their websites that are worth a watch. Both Oyster and Pelamis have been deployed at the European Marine Energy Centre (EMEC) at Orkney.
It would be nice if you could simply line these devices up - Pelamis in the deep water, Oyster in the shallow water and the Wavegen device onshore, but unfortunately it doesn't work like that. Decent size waves require a long "fetch" - and once the energy has been extracted by one of these devices that's it - you can't have the energy twice.
I happened to stop by Pelamis Wave Power this morning whilst out for a bike ride. A couple of their big tubes were visible in the construction shed. I wonder if these are the ones ordered by E.ON?
Monday 31 August 2009
Smart Grids - The Evolution of the Electricity Network
In the 20th century UK electricity networks evolved from a group of regional islands to a national grid. In the UK there are today approximately 140 "big" power stations. Traditionally the flow of electricity is "downhill" from generator, through distribution to the end user. The grid that carries this flow is aging - at least 40 years old in most cases.
Such a network will not be sufficient for the future. Renewable energy sources will be more numerous and more distributed. As individuals install their own small renewable energy sources it will be advantageous to be able to connect them to the grid to provide additional power. In other words there will be a need to integrate a diverse set of generation capabilities.
A network built around renewables will probably be more susceptible to variations in weather (for example wind turbines have to be shut off in high winds to prevent damage and in low wind they will generate less power.)
A smarter system for managing the generation and distribution of electricity will be required if we are to take advantage of this distributed generation and if we want to ensure security of supply.
Smarter use of electricity is envisaged, with consumers being able to make use of cheaper off-peak electricity (much like off peak travel is typically cheaper on the railways.) This leads to the idea of a two way network that manages information related to the supply of electricity - in many ways not unlike the internet that so many of us use for communication and information today.
To this end moves are afoot in Europe and the US to develop the technology to build so called Smart Grids.
Within Europe the Smart Grids European Technology Platform - http://www.smartgrids.eu/ is a consortium of interested parties focused on developing the technology for such a network. There are a number of papers on this site describing the vision for Europe and the Strategic Research Agenda.
There is an American Department of Energy document available
http://www.oe.energy.gov/DocumentsandMedia/DOE_SG_Book_Single_Pages(1).pdf which describes smart grids at a fairly high level - I'd recommend this as an easy introduction to the subject.
There is also an interesting paper from the Global Environment Fund with a US focus on the need to modernise the supply and management of electricity http://www.smartgridnews.com/pdf/TheElectricityEconomy.pdf
These are all fairly long documents - but the vision is similar. The electricity supply industry is ripe for modernisation.
Such a network will not be sufficient for the future. Renewable energy sources will be more numerous and more distributed. As individuals install their own small renewable energy sources it will be advantageous to be able to connect them to the grid to provide additional power. In other words there will be a need to integrate a diverse set of generation capabilities.
A network built around renewables will probably be more susceptible to variations in weather (for example wind turbines have to be shut off in high winds to prevent damage and in low wind they will generate less power.)
A smarter system for managing the generation and distribution of electricity will be required if we are to take advantage of this distributed generation and if we want to ensure security of supply.
Smarter use of electricity is envisaged, with consumers being able to make use of cheaper off-peak electricity (much like off peak travel is typically cheaper on the railways.) This leads to the idea of a two way network that manages information related to the supply of electricity - in many ways not unlike the internet that so many of us use for communication and information today.
To this end moves are afoot in Europe and the US to develop the technology to build so called Smart Grids.
Within Europe the Smart Grids European Technology Platform - http://www.smartgrids.eu/ is a consortium of interested parties focused on developing the technology for such a network. There are a number of papers on this site describing the vision for Europe and the Strategic Research Agenda.
There is an American Department of Energy document available
http://www.oe.energy.gov/DocumentsandMedia/DOE_SG_Book_Single_Pages(1).pdf which describes smart grids at a fairly high level - I'd recommend this as an easy introduction to the subject.
There is also an interesting paper from the Global Environment Fund with a US focus on the need to modernise the supply and management of electricity http://www.smartgridnews.com/pdf/TheElectricityEconomy.pdf
These are all fairly long documents - but the vision is similar. The electricity supply industry is ripe for modernisation.
Sunday 30 August 2009
How much energy do I use?
I started reading my gas and electricity meters about a year ago. I used to read them regularly many years ago and fell out of the habit. It's useful if for no other reason than to know if the utility companies' estimates are even close.
I subsequently discovered through David MacKay's book, the readyourmeter.org website. The idea is that you can enter your meter readings on the website (ideally on a fairly regular basis) and keep track of your energy usage, CO2 emissions and so on for your household or business. It's not the greatest website - it would benefit from being a bit more intuitive in terms of how to draw the graphs for your selected building(s). It is however a good idea in principle.
The other thing that could be done is to convert gas readings into kWh to make easier comparison with electricity. One's gas bill usually explains how to do this. The calorific content of natural gas is not constant across the network and a correction factor needs to be applied, however this is not usually very significant.
I subsequently discovered through David MacKay's book, the readyourmeter.org website. The idea is that you can enter your meter readings on the website (ideally on a fairly regular basis) and keep track of your energy usage, CO2 emissions and so on for your household or business. It's not the greatest website - it would benefit from being a bit more intuitive in terms of how to draw the graphs for your selected building(s). It is however a good idea in principle.
The other thing that could be done is to convert gas readings into kWh to make easier comparison with electricity. One's gas bill usually explains how to do this. The calorific content of natural gas is not constant across the network and a correction factor needs to be applied, however this is not usually very significant.
Anyway, from the readings over the last 12 months it seems that as a family we used 7500 kWh of electricity and 47000 kWh of gas. Given we are a family of six, that's not too bad - but if there were only four of us I suspect it wouldn't be a whole lot less. It works out at about 25 kWh per day per person. That said the gas usage is pretty high. We use gas for hot water, heating and cooking. It turns out as one might expect that the majority is used during the winter months for heating. We have an old, inefficient boiler - although replacing it is quite an expensive option. We live in an old house and the opportunities for improving the insulation are very limited - no loft and no cavity walls. We have for the most part switched to energy saving light bulbs.
What about transport? We are a one car family - we traded down from two cars about 5 years ago, mainly on economic grounds - and I started cycling to work - or in the winter cycling to the station and taking the train. That's about 3000 cycling miles and 2000 train miles per year. We cover about 6000 miles per year in the car - well below the national average, but certainly more than we need to. I fill the tank approximately every three weeks. I haven't done the sums to figure out how many kWh that translates to yet. Watch this space. Family bus usage is pretty limited. As a family we typically take one return plane flight per year to Europe. In the past I used to travel by plane fairly regularly as part of my job, but in recent years that has fallen to approximately one intercontinental and perhaps one European return flight per year. Again I haven't yet done the sums, but I expect that the plane travel dwarfs all our other travel energy usage.
I really don't have a clue how much energy we use in terms of the amount of "stuff" we buy - it's probably quite significant.
Of course, knowing how much one uses is one thing. Reducing it is another.
Saturday 29 August 2009
The future of energy - some stark choices
This series of blogs are my musings on the future of energy usage. I live in the UK, so my bias is towards that country - but the principles apply to the whole world - particularly the west where our thirst for energy is increasing at a probably unsustainable rate.
Much is being made of climate change and carbon footprints - but that may turn out to be the least of our worries. It will at least ultimately be a self correcting problem. I remain a man made global warming sceptic - mainly because the science is so difficult to be definitive about. There is plenty of bad science in the climatology world - but it suits a lot of people to perpetuate it.
The BIG problem as I see it is that the fossil fuels are going to run out. Exactly when is hard to say, but as the recent volatility of the oil price has shown, demand is starting to outstrip supply. It took a couple of billion years to lay down the coal and oil reserves. We are burning them up in only a few centuries - with the rate of extraction increasing exponentially.
My personal revelation came from reading David MacKay's book, Sustainable Energy Without the Hot Air (www.withouthotair.com). In it he does the sums to figure out how much energy we use in the home, transport and industry. for the UK it comes out as an average of 125 kWh per day per person, split approximately one third between each of the primary uses. He then looks at how much we might be able to realistically generate from renewable sources. If we cover the country in windmills, surround the coast with wave and tidal generation devices and switch to electric vehicles, we might just about make it. As he points out, renewable sources are diffuse, so we will need to cover the country and the coastline with a lot of generation capacity, be it wind, wave, tidal, solar, hydro, biomass or whatever.
One of the challenges today is with the economics of the problem. Installing one's own renewable energy sources is expensive with payback times often on the order of 15 to 20 years. As fossil fuels get more expensive and as economies of scale kick in, these payback times will reduce - but there isn't much financial incentive to "go green" at present. Of course, many people don't have the option - not living in places conducive to the installation of such devices.
Unfortunately I am not sure we have the luxury of time to allow these changes to come about through the natural course of things. I believe that legislation will be required to accelerate the switch-over and not just through carbon reduction legislation. More on that in the future.
The other problem that needs to be overcome is nimbyism. Everybody wants green energy, but not if they have to look at a windmill out the window - or a bird might fly into a rotor - or a myriad of other excuses. Frankly there are some very simple choices. Build a host of nuclear power stations to replace the existing oil, coal and gas fired stations, cover the country in renewable energy generators or wait for the lights to go out.
One of the challenges today is with the economics of the problem. Installing one's own renewable energy sources is expensive with payback times often on the order of 15 to 20 years. As fossil fuels get more expensive and as economies of scale kick in, these payback times will reduce - but there isn't much financial incentive to "go green" at present. Of course, many people don't have the option - not living in places conducive to the installation of such devices.
Unfortunately I am not sure we have the luxury of time to allow these changes to come about through the natural course of things. I believe that legislation will be required to accelerate the switch-over and not just through carbon reduction legislation. More on that in the future.
The other problem that needs to be overcome is nimbyism. Everybody wants green energy, but not if they have to look at a windmill out the window - or a bird might fly into a rotor - or a myriad of other excuses. Frankly there are some very simple choices. Build a host of nuclear power stations to replace the existing oil, coal and gas fired stations, cover the country in renewable energy generators or wait for the lights to go out.
Subscribe to:
Posts (Atom)
Posts
