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Energy Balance of a Wind Turbine

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My friend, who works for Shell (although not in an engineering capacity) claims to have remembered a radio interview in which it was 'proved' that the energy (or carbon) balance of a typical UK wind turbine was no better than a coal-fired power station over its lifetime. Appparently the foundations take a lot of energy to build, as does the steel pylon etc.

 

Anyone have the figures to hand?

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My friend, who works for Shell (although not in an engineering capacity) claims to have remembered a radio interview in which it was 'proved' that the energy (or carbon) balance of a typical UK wind turbine was no better than a coal-fired power station over its lifetime. Appparently the foundations take a lot of energy to build, as does the steel pylon etc.

 

Anyone have the figures to hand?

88kg of of CO2 released in the combustion of 1GJ coal.

 

You are asking what the embodied energy of the construction materials are?

 

Cement 5-9 MJ/kg

Iron 20-25

Aluminium 227-342

Copper 60-120

 

Hope that helps.

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The figures usually quoted for the energy payback period (time taken for the turbine to generate as much energy as used in its manufacture and installation) are about 3-10 months for modern wind turbines (type used in wind farms), so over a 20-year lifetime the energy payback ratio (energy produced compared to energy used to construct it) is something like 24—80, but obviously quite variable depending on the site and conditions.

 

Danish Wind Industry Association – Energy Payback Period + lots of figures, 1997.

http://www.windpower.org/en/tour/env/enpaybk.htm

 

But it's quite possible that a UK offshore farm in deepish water could have a much lower EPR :D

 

Comparing Energy Payback Ratios, EPR

NatGas 4

Coal 12

Fission 16

Fusion 26

Wind 23

 

Source: EPRs for Natural Gas plant

http://fti.neep.wisc.edu/presentations/pmeier_energy.pdf

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There more to think about than payback times.

 

Think about the impact of hyperinflation...

 

If you build a Gas-fired electricity generation plant, you have the (fixed, historical) capital cost, and the ongoing fuel cost. In a world of rapidly rising oil prices and inflation, the capital costs get inflated away, and the fuel costs continue to rise with inflation. This plant will wind up having a high price of electricity

 

What about a wind farm? Expensive to build maybe. But the capital cost shrinks through inflation, and the ongoing maintenance cost is tiny.

 

How about a Nuclear plant? Again, a huge capital cost. But this is better than the Natgas power plant, because the relative cost of the uranium is tiny next to the fuel cost

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Figures from the hydro-Quebec study give energy pay back ratios of 80 for wind energy and 5-7 for conventional coal. So wind turbines produce 80 times as much energy as they consume in their construction over their operational lifetime.

 

Out of interest nuclear is 16!

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I caught the tail end of a programme on radio two at lunchtime. It was all about dealing with the energy crisis.

 

One very irate caller was objecting to wind farms and claimed that they were completely useless as an energy source and a blot on the landscape. She claimed that wind power couldn't replace ordinary power stations and ordinary power stations were still needed. But for most of the time the power stations would be running at half capacity which would be very inefficient and hence negate the benefits of the windfarm.

 

I have no idea whether this is true or not but I do know that lots of people are going to object to wind farms etc being built. In fact as the very sensible government minister guy said some people will just object to anything being built whether its a wind farm, electricity sub-station or a nuclear plant. People want the energy but everyone objects to it being in their own backyard.

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She claimed that wind power couldn't replace ordinary power stations and ordinary power stations were still needed. But for most of the time the power stations would be running at half capacity which would be very inefficient and hence negate the benefits of the windfarm.

 

She's partly right. Nothing can replace the convenience and energy density of fossil fuels. The focus should be on energy conservation. Trying to cure the symptom is futile, it's the disease that needs addressing.

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She's partly right. Nothing can replace the convenience and energy density of fossil fuels. The focus should be on energy conservation. Trying to cure the symptom is futile, it's the disease that needs addressing.

 

Yes I think life will have to change. Wearing jumpers and thermals might just be fashionable again when oil prices go up another ten times.

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