Peat, windfarms and wild lands: does wind power reduce emissions in Scotland?
Scottish ministers could be “deluding” the public with the argument that wind turbines reduce carbon emissions, according to a Scottish conservation charity – which dismisses figures from National Grid and the Department for Energy and Climate Change showing they do.
In the Scottish edition of the Sunday Times (not online), John Milne of the Scottish Wild Land Group (SWLG) says:
“…we fear the potential consequences of allowing those in power to delude the public, and possibly themselves, that the widespread pursuit of wind farming in Scotland will make any meaningful contribution towards combating climate change, the greatest challenge facing humanity.”
The group opposes the expansion of windfarms in Scotland because, it says, Scottish wild land is “uniquely important to Scotland’s identity”.
SWLG says it doesn’t know if windfarms reduce carbon dioxide emissions, but it’s not convinced. It’s calling for an independent energy commission to look into the question.
It might be easy to dismiss SWLG’s argument on the basis that international bodies like the International Energy Agency accept the idea that wind power reduces emissions. But the critique raises some interesting questions about how emissions reductions are calculated, and lets us look at the issue in a bit more detail.
Fossil fuel as backup
No-one’s arguing that wind farms don’t generate electricity. The question is, what does that mean for emissions?
Some critics of wind have said it doesn’t reduce emissions because it requires fossil fuel plant as backup – for when the wind isn’t blowing. Professor Gordon Hughes wrote a report for climate skeptic thinktank the Global Warming Policy Foundation, arguing less efficient gas power stations would need to be used because they are easier to turn on and off. He said this would make the whole process even more carbon-polluting than if the windfarms didn’t exist in the first place.
Imperial College dismissed this as a “nonsense scenario“, saying that modern, efficient gas turbines could be used as backup instead. In evidence submitted to the Scottish Parliament, system operator the National Grid agrees. It calculated that the need to turn fossil fuel power stations on and off in order to back up wind power would reduce the expected emissions benefit of using wind to generate electricity by less that 0.1 per cent.
What fuel does wind replace?
National Grid concludes that over an 18 month period British onshore wind turbines save about 10.9 million tonnes of carbon dioxide.
But SWLG takes issue with National Grid’s calculation, because it assumes wind turbines displaces polluting gas power stations. SWLG isn’t convinced that that’s what happens.
Anti-wind body the Renewable Energy Foundation recently levelled the same criticism at a similar calculation by the Department for Energy and Climate Change (DECC). What if wind power displaces nuclear power instead of gas or coal? The emissions savings would be a lot less significant.
SWLG argues that it’s impossible to tell, and we haven’t been able to find much official analysis out there.
Last September energy bloggers Mark Lynas and Chris Goodall carried out an analysis for the Guardian of National Grid data. Lynas and Goodall’s work indicated that gas does displace wind. In fact, they found a fairly simple relationship – one megawatt hour of wind typically means the UK grid used one less megawatt hour of gas-derived electricity. They say:
“This means that actual CO2 savings can be calculated from the data with a high degree of accuracy – these are not guesstimates from models, but observations of real-world data.”
Lynas and Goodall conclude that UK onshore wind turbines currently save around 6.1 million tonnes of carbon dioxide – or about four per cent of the UK’s emissions from electricity – a year.
Wind farms and peat
SWLG also point to recent research from Aberdeen University on the effect of building windfarms on carbon-rich peatlands. Building on peatlands can mean draining the soil, which can release large amounts of carbon dioxide.
SWLG says the research “suggests that windfarms built on peat will never save as much carbon dioxide as released by their construction”. But when we spoke to the researchers back in September, they gave a more nuanced impression of what they had found.
Some peatland is pristine – totally undamaged – and some has already been affected by development. It’s more harmful to build windfarms on the pristine peatland. Lead researcher Jo Smith told us:
“Building wind farms on degraded peat is more acceptable â?¦ That can easily result in some carbon benefit. So it really depends on which peatland we are developing wind farms”.
The calculation is quite complicated, and as the power sector decarbonises wind farms built on peat are going to compare less and less favourably. But Smith said that with good practice even a windfarms on pristine peatland
“…can save emissions compared [to] the present day fossil-fuel mix used to generate electricity.”
Good practice guidance has been developed to avoid windfarms being built on pristine peat.
Transparency
In its email to us, SWLG stresses that it accepts the threat posed by climate change, and says isn’t sure whether wind turbines reduce emissions. The group wants more transparency, arguing that the figures from DECC and National Grid are “biased and highly opaque”.
It says the figures will be impossible for nearly everyone to wade through – removing the public’s right to understand the issue clearly and make a democratic decision.
This problem is illustrated by the fact that all the participants in the debate seem to be using similar data. SWLG, the Scottish government and the renewables industry all cite the National Grid paper, for example.
Overall, the SWLG doesn’t seem to have any killer arguments – according to the data we’ve seen, windfarms do reduce greenhouse gas emissions. But some clearer figures and effective communication of them might help clarify the debate.