60 second guide to... Wind power

Wind turbine: 60 second guide to wind power

Does wind power provide a solution to supplying our power or are there too many concerns over the consistency of wind energy?

In the broadest sense, ‘wind power’ is any form of energy captured from moving air – including the mechanical energy of traditional windmills. But today the phrase is used almost exclusively to refer to the generation of electricity by wind turbines.

There are many advantages to creating electricity from the wind. Once you’ve built the turbines, they require no fuel to operate and produce no emissions of CO2 or other pollutants. Compared with other renewable sources, wind power is relatively cheap – especially in windy countries such as the UK.

Wind power today

Although only around 1 per cent of the world’s total electricity supply comes from wind, the figure is much higher in some countries. Denmark tops the list with around a grid powered 20 per cent by wind.

The UK gets around 1.5 per cent of its electricity from wind farms, but this proportion is set to rise over the coming decade. The government plans a massive expansion of wind power in the UK to help meet its target of 20 per cent renewable energy by 2020.

Wind farms can be built on the land (onshore) or at sea (offshore). Offshore wind is more expensive but for the UK it offers higher energy yields – around 100,000 gigawatt hours per year, compared with 50,000 for onshore.

The intermittence issue

It’s sometimes said that wind farms aren’t as green as they seem because they function intermittently – making electricity only when the wind blows. Therefore, they need to be backed up by fossil fuel power stations running on standby.

But this problem is vastly overstated according an in-depth report by the UK government’s Sustainable Development Commission. The report states that, as long as wind power doesn’t exceed around 20 per cent of the grid’s supply, then “the carbon penalty for having to have additional conventional plant on reserve duty to compensate for the variability of wind (which is in any case usually predictable) is very small.”

Wind power debates

A common criticism of onshore wind power is its impact on the visual environment. Some people consider the turbines a blot on countryside landscapes and have lobbied planners to block the building of new wind farms.

Another objection is that wind turbines may pose a risk to bird life, and marine life in the case of offshore wind farms. However, these risks are sometimes exaggerated. The RSPB has objected to various wind farm proposals but, overall, supports renewable power and considers that “appropriately positioned wind farms do not pose a significant hazard for birds”.

Other possible downsides to wind farms include impacts on local rainfall patterns, the risk of collisions with ships and noise pollution. But green campaigners point out that all of these disadvantages need to be weighed up against the much greater risks posed by global warming. This includes everything from floods and drought to the devastating loss of biodiversity.

On a smaller scale, wind energy can also be used to generate green energy at home. To find out more about putting a wind turbine on your roof, see our 'How to' guide to wind power.