Wind turbines.?
Over what period of time does a turbine have to run, using average yearly statistics for local (UK) wind patterns, does it have to run to generate sufficient power to recoup its energy consumed imn a dust to dust scenario? This to include the manufacture, construction and recycling/disposal of the structure and the rare metals, lead, cadmium etc. used in its construction.
Answers:
they are a total waste of time
Millions of years probably.
It takes a few months for them to make back more than the energy it takes to build, maintain and decommission them.
check out:
http://en.wikipedia.org/wiki/wind_power.
If you are talking about domestic wind turbines, in most places in the UK they are a waste of time, and I imagine the time to break even on the build and dispoasl costs would be measured in the 10s of years. On a commercial scale things are different because the turbines are far larger, taller and in areas with high natural wind. Here is a quote from a recent new scientist article:-
" .Building for a Future magazine, which supports renewable energy, published an analysis of micro wind machines. In winds of 4 metres per second - higher than average for most of the UK - a 1.75-metre turbine produces about 5 per cent of an average household's annual electricity. To provide the 50 per cent Dunster advertises, you would need a machine 4 metres in diameter, which would rip the side off your house.
What's more, turbulence makes wind generators even less efficient, and to avoid it you must place them at least 11 metres above any obstacle within 100 metres. On most houses, this means constructing a minor hazard to aircraft. And the higher the pole, the more likely you are to inflict serious damage on your house. In almost all circumstances, micro wind turbines are a waste of time and money.
In Canada, a wind turbine will cost approx $600, plus another $500 for the mast. Based on cost alone, I would imagine that this cost could be recouped within a year or two.
This is a straight lift from Wikipedia on Energy Return on Energy Invested.
"There exists no formal standard on the use of measure to calculate EROEI. In addition, the form of energy of the input can be completely different from the output. For example, energy in the form of coal could be used in the production of ethanol.
"How deep should the probing in the supply chain of the tools being used to generate energy go? For eg. If steel is being used to drill for oil or construct a nuclear power plant, should the energy input of the steel be taken into account, should the energy input into building the factory being used to construct the steel be taken into account and amortized? Should the energy input of the roads which are used to ferry the goods be taken into account? These are complex questions evading simple answers.
"However, when comparing two energy sources a standard practice for the supply chain energy input can be adopted. For eg. consider the steel, but don't consider the energy invested in factories deeper than the first level in the supply chain.
Energy return on Energy invested does not take into account the factor of time. Energy invested in creating a solar panel would have been via a high power source like coal, but the return happens very slowly, i.e. over many years. Some believe this means the EROEI measure should be refined further.
"There also exists no formal accounting rules for the consideration of waste products that are used in the production of the ultimate output. For example, waste products generated in the production of ethanol, makes the calculation of this fuel's true EROEI extremely difficult."
This extract shows how complicated the issue is. George Monbiot's article that Jammy mentions (lifts) attempts to use the EROEI argument against small-scale wind, however the case is far from proven.
It is true that in built up areas the turbulence generated by buildings would make it hard to site a turbine, however the greatest argument is that it will generate a very small percentage of a house's energy consumption per year. We need to start thinking big, and soon because climate change is not going to respond to such small-scale actions which mainly serve to make us feel better.
The story goes that the big ones will recoup their carbon debt in five years. Those on the roof of a house take at least forty years - then you start getting you money back if they last that long.
BUT how do you store the energy when it is not needed so you can use it when it is?
RoyS
What qualification did Professor Messer achieve in order to give himself the title of professor?
officially how many landlocked countries are there?
Are hybrid cars really so much more environmentally friendly?
What did the fossil do when it was alive?
Balancing and writting ionic equations?
Can you have a Scalene Right Angled triangle?
Which of the following are compounds? O2, CO2, H2O,H2?
How likely is it that someone will develop an anti gravity device at some point in the near future?
Answers:
they are a total waste of time
Millions of years probably.
It takes a few months for them to make back more than the energy it takes to build, maintain and decommission them.
check out:
http://en.wikipedia.org/wiki/wind_power.
If you are talking about domestic wind turbines, in most places in the UK they are a waste of time, and I imagine the time to break even on the build and dispoasl costs would be measured in the 10s of years. On a commercial scale things are different because the turbines are far larger, taller and in areas with high natural wind. Here is a quote from a recent new scientist article:-
" .Building for a Future magazine, which supports renewable energy, published an analysis of micro wind machines. In winds of 4 metres per second - higher than average for most of the UK - a 1.75-metre turbine produces about 5 per cent of an average household's annual electricity. To provide the 50 per cent Dunster advertises, you would need a machine 4 metres in diameter, which would rip the side off your house.
What's more, turbulence makes wind generators even less efficient, and to avoid it you must place them at least 11 metres above any obstacle within 100 metres. On most houses, this means constructing a minor hazard to aircraft. And the higher the pole, the more likely you are to inflict serious damage on your house. In almost all circumstances, micro wind turbines are a waste of time and money.
In Canada, a wind turbine will cost approx $600, plus another $500 for the mast. Based on cost alone, I would imagine that this cost could be recouped within a year or two.
This is a straight lift from Wikipedia on Energy Return on Energy Invested.
"There exists no formal standard on the use of measure to calculate EROEI. In addition, the form of energy of the input can be completely different from the output. For example, energy in the form of coal could be used in the production of ethanol.
"How deep should the probing in the supply chain of the tools being used to generate energy go? For eg. If steel is being used to drill for oil or construct a nuclear power plant, should the energy input of the steel be taken into account, should the energy input into building the factory being used to construct the steel be taken into account and amortized? Should the energy input of the roads which are used to ferry the goods be taken into account? These are complex questions evading simple answers.
"However, when comparing two energy sources a standard practice for the supply chain energy input can be adopted. For eg. consider the steel, but don't consider the energy invested in factories deeper than the first level in the supply chain.
Energy return on Energy invested does not take into account the factor of time. Energy invested in creating a solar panel would have been via a high power source like coal, but the return happens very slowly, i.e. over many years. Some believe this means the EROEI measure should be refined further.
"There also exists no formal accounting rules for the consideration of waste products that are used in the production of the ultimate output. For example, waste products generated in the production of ethanol, makes the calculation of this fuel's true EROEI extremely difficult."
This extract shows how complicated the issue is. George Monbiot's article that Jammy mentions (lifts) attempts to use the EROEI argument against small-scale wind, however the case is far from proven.
It is true that in built up areas the turbulence generated by buildings would make it hard to site a turbine, however the greatest argument is that it will generate a very small percentage of a house's energy consumption per year. We need to start thinking big, and soon because climate change is not going to respond to such small-scale actions which mainly serve to make us feel better.
The story goes that the big ones will recoup their carbon debt in five years. Those on the roof of a house take at least forty years - then you start getting you money back if they last that long.
BUT how do you store the energy when it is not needed so you can use it when it is?
RoyS
The answers post by the user, for information only, UKQnA.com does not guarantee the right.