Wind farms don’t need extra backup

Posted on April 26, 2012 by

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This letter was published in the Bega District News last Friday 20th April.

It answers one argument that anti-windfarm campaigners commonly raise: even though many of them don’t believe in climate change anyway, some suggest that wind farms actually have high greenhouse gas emissions because of the need for constant “spinning reserve” in fossil fuel power stations, just in case the wind suddenly disappears.

Technical veracity

As one who works providing training services in the energy sector, I read John McKerral’s letter to the editor (17/2) with some concern regarding its technical accuracy.

I neither advocate nor oppose the proposal for Twofold Bay; my issue with Mr McKerral is the technical veracity of his argument.

My delay in responding was due to my need to refer his letter to other technical experts in the energy sector so as to be sure of my facts.

The electricity network always has some “spinning reserve” built into it.

A typical coal-fired power station has about 10 per cent spinning reserve to take up any unexpected load on the network (such as the failure of a generator in the network, as happened recently when the Eraring Power Station on the Central Coast failed a few months ago).

Wind turbine generators complement the base load generation of the conventional power generation stations.

Yes, winds do ebb and flow, as Mr McKerral points out.

And the remote control stations that operate the wind turbine generators use complex algorithms to harmonise the generation across their various sites such that the total variability of power generation is minimised.

If significant power variation was experienced, then the spinning reserve of the existing network could accommodate it.

There is no need to fire up gas turbine generators “just in case”.

Gas turbine generators are used for peak load demand such as very hot days when everyone turns on their air conditioner.

So does the spinning reserve of the coal-fired power stations negate the CO2 savings of wind generated power?

No.

I say this with confidence by referring to the report: “GHG [Green House Gas] and Cost Implications of Spinning Reserve for High Penetration Renewables, Technical Assessment Report 73 – March 2008” from the CRC for Coal in Sustainable Development.

Quoting from the executive summary: “The often held view that operating larger fossil plants at part load to provide spinning reserve would negate the greenhouse gas emission benefits of wind is false”.

Given that this technical report comes out of the coal industry itself, I doubt it is biased towards wind generators.

The visual amenity of large-scale wind turbine generators is part of a separate and valid debate.

However, let us not simply discount a valid form of clean energy generation on falsehoods about the actual impact upon greenhouse gas reductions.

David Neyle
Tathra