Wind turbines

[PhilLew]

I've been thinking, how much energy does it take to make, transport and install a wind turbine and all the associated cabling etc. compared to the amount of energy they will produce over there expected lifespan.

I mean the whole process from mining the Boxite, smelting it into Aluminium, the fabrication, transport (I have been told most of the ones here come from Germany) also the digging and laying of cables not to mention the copper mining process for the cables and motor windings in the first place.

Are they realy as environmently friendly as we are led to believe

[mjhunt59]

i think there was a recent survey that said they don't produce anywhere near as much energy as government makes out

[jake-the-peg]

Which "recent survey" would that be then?

You'd have to compare it to the cost of creating a coal or gas powered station though and there's an awful lot of concrete that goes into one of those! not to mention all the steel that goes into the boilers and the cost of transprting the fuel.

I'd be really surprised if they were more efficient in infrastructure


Not sure about figuresfor wind turbines but here's some data on Solar panels

http://www.otherpower.com/otherpower_solar_new .html

A SOLAR POWER MYTH

We've often heard the myth that "it takes more electricity to manufacture a solar panel than it will ever put out." This is simply not true...this myth may have started during the Ronald Reagan era. This is of course a very difficult statistic to calculate, but according to the National Renewable Energy Laboratory in Golden, CO, a study has been done to answer the question. The study found that single-crystal panels reach the energy payback point in 5-10 years, polycrystalline panels in 3-5 years, and amorphous silicon panels in 0.5-2 years

[Loosehead]

As jake points out, if you take the construction of the wind turbine in isolation then you can say it's a long time before it pays back the energy. However the systems that would otherwise have to product the energy, ie a power station are worse. This is the case for any of the "renewable sources", you can do a similar calculation for a nuclear power station. Ie how much energy is used to build it versus how long the reactor takes to repay that investment when it's operational.

[heathfield]

A search on Google shows that wind turbines in the UK are said to return the energy used in their construction within three to six months. This compares with a conventional power station energy return of six to eight months.

But a recent survey by the official UK energy watchdog 'Ofgem' concludes that wind energy is almost twice as expensive to produce as nuclear energy. And this estimate includes nuclear de-commissioning costs.

[jake-the-peg]

Yes, this is the perennial problem with most renewables - you simply can't whistle up a storm half time in the middle of a cup final when everybody nips out to put on a cup of tea.

So there's a discrepancy in how you account for renewables. If you start with the assumption that you want to replace many or all traditional power stations with them then you need to build so many that they become stupidly expensive.

However if you build them not to replace traditional ones but so that when there's the wind you can turn off expensive gas powered stations then they start to look much more attractive.

Renewables will never replace fossil fuels but used sensibly they'll help get us over then next 30 years or so when the first fusion reactors start to come on line