Wind power

I was talking with my father yesterday, and he claimed that the problem with wind power is that the energy required to build a wind turbine exceeds the energy generated by the turbine during its operational life. This seemed a little strange, so I thought I would see what I could find about this. It seems that the effectiveness of a power system is measured by the Energy Return on Investment (EROI) which – according to this – is the usable acquired energy divided by the energy expended.

I haven’t researched this extensively, but according to The Oil Drum, the average EROI for wind turbines is 18.1. It increases with increasing turbine size (or turbine power) and can reach as high as 40. This seems to compare very favourably with other power generation sources. The figure below shows that the EROI can be as low as 1 (for biodiesel), as high as 100 (for hydro), but is typically between 10 and 40 (nuclear, for example, seems to be 10).

EROI values for different forms of power generation.

EROI values for different forms of power generation.

There may be valid issues with the use of wind turbines to generate energy (as there are for most energy sources), but it seems that the argument that it costs more energy to build the turbine than it returns during its operational life, is just completely wrong.

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8 Responses to Wind power

  1. Rachel says:

    That’s interesting. I didn’t realise solar would have such a low return. I wonder how geothermal rates.

  2. Yes, although I haven’t quite worked out what “solar flat plate” and “solar collector” are. From what I’ve been reading now, solar (PV) probably has an EROI of greater than 6. Not fantastic, but not ridiculously low either.

  3. The production of the silicon wafers costs a lot of energy. That is probably why the machines to make them are designed in the West and the modules are installed here, but the energy intensive production of the solar cells is done in China, outside of the Kyoto protocol and then the energy (and its CO2 emissions) is imported into the West again. Then the climate “sceptics” complain that China emits so much CO2, whereas it is to a large part the CO2 of the West.

    For the climate is does not matter where the CO2 is emitted. The rules should reflect that.

  4. Gavin's Pussycat says:

    My little brother was in this misperception too, until I provided him with a few links. I am pretty sure that someone is actively spreading this lie — for money.

    But as you imply, it doesn’t matter really if the number is 6 or more. That means that “net” is 84% of “gross”, good enough for government work. E.g., wind turbines contain huge amounts of steel and concrete, which take fossil fuels to produce — today. Some day soon this will have to change, and then this “embodied energy” just represents a life-cycle 5% efficiency loss. Such alternative production processes, like steel production using hydrogen or electric arc, are under study or already in specialized use.

  5. MightyDrunken says:

    The favourite attack against wind power at the moment is the idea that the cycling of fossil fuel power generators to follow the variation in wind power generation eats up most of the CO2 savings and creates extra cost. For instance the Bentek study, “How less became more” and the le Pair and de Groot study, “The impact of wind generated electricity on fossil fuel consumption”.

    I haven’t read the le Pair study and I suspect the Bentek study may over estimate the cycling caused by wind.

  6. Interesting, I hadn’t come across those. I shall have to try and give them a read. Their conclusions would seem surprising if moderns wind turbines do indeed have an EROI of 40 though. That’s a pretty impressive return on energy investment.

  7. tonylurker says:

    There are several of them, the one I keep running into is ATI Senior fellow John Droz Jr., a self proclaimed “energy expert”.

  8. Pingback: Another Week of Global Warming News, June 9, 2013 – A Few Things Ill Considered

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