Site windfarms carefully, for peat's sake
- 26 Feb 2013, 13:50
- Carbon Brief Staff
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
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".
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
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
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
"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 … That can easily result in some carbon benefit. So
it really depends on which peatland we are developing wind
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
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
"[B]uild wind farms - we need them; but
avoid siting them on pristine peatlands".
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
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."
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
4pm - Updated with some more input on pristine vs.
non-pristine peat from the researchers.