Bogs and the wrong sort of wind

Wind turbines can often be a contentious issue, as Donald Trump’s recent spats with Alex Salmond have shown. Despite this, electricity generation using onshore wind turbines is projected to continue making a large contribution to the UK’s renewable energy budget. Peat bogs are often identified as suitable locations for wind farms, but what impact will wind turbines have on these important ecosystems?

So I’ve heard that peat bogs are important…

They are. Over the last 10,000 years, peat bogs have captured carbon dioxide from the atmosphere, storing it in deep organic deposits. Scientists estimate that the UK’s peat bogs store at least 1.3 billion tonnes of carbon – losing 12% of this would be equivalent to the total greenhouse gas emissions from the UK population over a whole year. Peat is regarded as a non-renewable resource, due to the long periods it takes to accumulate, and there is a compelling environmental argument for its protection.

How do wind farms affect peat bogs?

Many of the UK’s onshore wind farms are located in upland areas where peat bogs are often found. Peat bogs are attractive sites for wind farms, because they make poor agricultural land and are frequently windy, but construction of wind turbine foundations, access roads and works compounds can have major effects on peat bog health. The most serious problems are:

  • Removal of peat and vegetation for turbine construction prevents the peat bog from capturing carbon. Instead, the affected area becomes a source of carbon, in the form of carbon dioxide and methane.
  • Drainage is often necessary in the construction of turbine foundations and access roads. Lower water levels can lead to increased emissions of carbon dioxide.

Are the impacts of wind farms on peatland important?

The release of greenhouse gases associated with wind farm construction has the potential to cancel out the carbon emission savings associated with wind energy. These effects can be summarised as the carbon payback time. Carbon payback time is an important aspect of wind farm development. It is the period of wind farm operation necessary to generate sufficient carbon savings to balance the emissions incurred during development. Wind farms only start to achieve carbon savings after the payback time has elapsed, so if the payback time exceeds the lifetime of the wind farm, no carbon benefits will be achieved.

A study by Dr Dali Nayak of Aberdeen University for the Scottish Government calculated that carbon losses from wind farms built on peat bogs could cancel out up to 77% of the potential carbon savings associated with wind power.

The future of UK wind

The UK Government is committed to a target of 15% renewable energy generation for the UK by 2020 and wind turbines are one of the most established renewable technologies – the largest source of renewable energy, second to biomass. The Department of Energy and Climate Change expects onshore wind generation to increase between four and five times in order to meet the 2020 targets.

Finding a balance

There is pressure to expand the UK onshore wind energy resource so that it forms a key component of the UK’s renewable energy mix by 2020. Upland peat bogs are often perceived as ideal wind farm locations because there is little land use pressure from agriculture and they are typically windy places, but greenhouse gas emissions from peat bogs caused by disturbance from wind farms can cancel out the benefits associated with renewable energy. The bottom line is: to ensure the best returns from wind farms, you have to be careful where you put them – and peat bogs may not be the answer.