Site windfarms carefully, for peat’s sake
New research on the pros and cons of building wind farms on peat bogs “threatens the entire rationale of the onshore wind farm industry”, the Sunday Telegraph claims. But a conversation with the authors suggests the paper’s implications are being overspun.
A front page story in the Sunday Telegraph claimed “potentially devastating research” about the impact of wind farms on peatlands is only months away from publication.
The research in question looks at the consequences of building wind farms on peatland – waterlogged soil that contains large amounts of carbon. According to Sunday’s article, the research shows “thousands of Britain’s wind turbines will create more greenhouse gases than they save”.
Carbon-rich land
Generating electricity using wind power should cut carbon emissions. But building on carbon-rich peatlands can mean draining the soil, which releases large amounts of carbon dioxide. A team from the University of Aberdeen devised an emissions calculator to find out whether building wind farms built on peat bogs could negate their emission-cutting benefits.
The Sunday Telegraph picked up on the team’s most recent findings, which the scientists announced in a letter to Nature last year but have not yet published in full. According to the Sunday Telegraph, the new calculation shows peatland wind farms cut greenhouse gas emissions less than previously thought.
A nuanced approach
We spoke with the authors to learn more about the research. They pointed out that their paper doesn’t challenge the idea that windfarms are low carbon. Dr Jo Smith, lead author on the research, tells Carbon Brief:
“The Telegraph article was making a negative statement about onshore windfarms in general. This is not our view or the message from our paper.”
Co-author Dr Dali Nayak explained to us the team’s conclusion was rather more nuanced. She describes the findings as:
“[C]onstructing wind farms on almost any peatland will result in more net carbon emissions after 2040”.
There are two important parts of the paper’s findings which need to be flagged here: what kind of peat is being built on, and over what time period carbon savings are measured.
Pristine vs degraded peatland
Some peatland is pristine – relatively untouched by humans. Some is already degraded, having been drained in the past for construction or agricultural purposes.
Building windfarms on pristine peatland releases more carbon than building on peatland that has already been drained. Smith explains:
“If windfarms are constructed on non-degraded peatlands, the drainage of the peats causes them to start emitting carbon. If this is left unchecked, then eventually the construction of the windfarm will result in all of the carbon held in the peat being lost.”
If the carbon in the peat is lost because of the windfarm, it’s unlikely to mean the windfarm saves emissions over its lifetime. But for already-degraded peatland, there isn’t the same degree of carbon loss. Nayak tells 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 Sunday Telegraph’s article mentions the distinction between pristine and degraded peat. But the piece also claims this research “threatens the entire rationale of the onshore wind farm industry”.
This seems like hyperbole. Co-author of the research, Professor Pete Smith emphasises he thinks wind power has an important role to play in electricity generation over the next few decades. He says:
“[B]uild wind farms – we need them; but avoid siting them on pristine peatlands”.
Decarbonisation
The forthcoming study extends the analysis of wind farms built on peat bogs to cover the next thirty years – the expected lifetime of a wind farm.
The scientists take this longer-term view to show that as the rest of the power system decarbonises, windfarms on peatland become less of a good idea. Jo Smith explained to us:
“Because our economy is decarbonising, the amount of fossil fuels used to generate electricity is falling. This means that the carbon emission saving achieved by generating electricity using non-fossil fuels also falls.”
The new study assumes that more and more electricity will be low carbon in coming decades. Because of this, over time any net carbon emissions from wind farms built on peatland become more significant.
The Sunday Telegraph concludes the new research has “changed the equation, making the [carbon] comparison less favourable to all peatland wind farms.”
But this is actually discussing a comparison with a low carbon energy system in 2040, not today’s fossil-fuel reliant one.
Importantly, if construction is managed well, even windfarms built on pristine peatland can still be preferable – in carbon terms – to today’s carbon-intensive system of electricity generation. Jo Smith says that with good practice, “the windfarm can save emissions compared [to] the present day fossil-fuel mix used to generate electricity.”
Windfarm planning
Nevertheless, the longer term comparison shows, the researchers say, that building wind farms on pristine peat is a bad idea for carbon emissions. And Jo Smith points out:
“It might, of course, be better to avoid putting wind farms on these sites for other environmental reasons, but our arguments are centred on carbon only.”
Aedán Smith, head of planning and development for RSPB Scotland tells us “a lot” of windfarms are currently being built on peat in Scotland. But that covers “a massive range of peat soils ranging from undisturbed peat bogs to agricultural land with a lot of carbon content” – and it’s important to differentiate between the type of sites.
Planners, conservationists and renewables trade groups do appear to be aware that building on peatland could counteract windfarms’ carbon cutting benefits. Good practice guidance developed by environmental groups in association with the Scottish renewables industry says “every reasonable effort should be made to avoid significant adverse effects” in protected peatlands.
Coming right up to date, a set of updated guidance proposed by government advisors Scottish Natural Heritage is currently under consultation. It says that building on pristine peat bogs should be avoided. This seems like good news for the researchers, and for the carbon footprint of British wind farms.
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