Background
Climate change is projected to cause rising temperatures and changing weather patterns. These may result in the output of wind farms changing over time. A variety of studies have been undertaken which show how the amount of electricity generated in future will change as a result of climate change.
Figure 1 Ardrossan Wind Farm in Ayrshire, Scotland
Considerations
The amount of electricity generated at any particular instance is dependent on wind speed cubed. This means a small increase or decrease in wind speed produces a corresponding greater increase or decrease in electricity generation. For example a 5% increase in wind speed will typically result in a 15.7% increase in electricity generation.
Climate Change is forecast to cause extreme weather events to be more severe and more frequent. This means that the level of damage by storms is set to increase over time – potentially meaning more frequent outages and higher maintenance and repair costs.
Changes in temperature will also have some effects. Air density reduces as temperature increases which means electricity generation from a warm air flow is slightly less than generation from a cold air flow. Very low temperatures can cause icing which can also reduce or stop generation from wind turbines.
In practice weather at any wind farm is highly variable with variations from one day to the next not being related to climate change. It is difficult to accurately forecast what impact climate change will have when there are so many, essentially random variations, anyway.
Nevertheless a number of studies have been undertaken which make predictions for particular climate change scenarios, particular wind farms, countries or continents and particular future time periods. Many of the studies’ findings contradict each other.
Predicted effects from some of the studies are summarised below:
North West Europe – Generation is expected to increase by around 6% between 2020 and 2049
Mediterranean – Generation is expected to reduce by around 9% in winter between 2020 and 2049
Baltic Sea – General small increase in generation to 2100
Eastern Europe – General small reduction in generation to 2100
Germany – Wind speeds will increase slightly in winter and decrease slightly in summer to 2100
UK – Wind speeds will increase in northern Scotland and the north Atlantic whilst decreasing in southern England and the Channel
UK – Winter wind speeds will increase whilst summer wind speeds will decrease
Ireland – Winter wind speeds will increase whilst summer wind speeds will decrease
USA – Wind energy generation is set to increase between 2038 and 2070
Conclusions
The range of predictions in the studies means that no firm conclusions can be drawn. Indications are that generation from wind farms in northern and western parts of the UK are set to increase in winter as a result of climate change.
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