Introduction
The UK is the windiest country in Europe. A typical turbine in the UK will generate over 4.7 million units of electricity each year. That's enough to make 170 million cups of tea, to run a computer for 1620 years, or to meet the electricity demands of more than 1,000 homes for a year. Every unit of electricity from a wind turbine displaces one from conventional power stations. As a result wind turbines in the UK currently prevent the emission of one and three-quarter millions tonnes of carbon dioxide each year. Wind is the fastest growing energy source worldwide, and has been for over a decade, with an annual growth rate of 30 per cent.
South west focus
The UK has the best wind energy resource of any country in Europe, and South West England has areas of strong wind resource in every one of its seven counties. There are over 100 turbines installed in the region. Most of these form part of seven wind farms in Cornwall, which produce the equivalent of the power used by 25,000 homes and stop over 60,000 tonnes of carbon dioxide pollution entering the atmosphere.
Resource studies undertaken for the region suggest that the south west could generate up to 18 per cent of all its power needs from wind energy without encroaching on protected areas. Because of wind energy’s favourable economics and the south west’s strong resource, it is widely expected that the region will need wind energy to contribute at least two thirds of its 2010 target. The South West still has a long way to go to achieve this. A number of wind energy schemes have recently been given approval by the planning inspectorate and there are many more in the planning system or expected soon.
South West Public Engagement Protocol for Wind Energy
The South West operates a Protocol on public engagement around wind energy proposals in the region, and Regen SW encourages all developers interested in working in the region to sign up. In doing so, developers will receive support from Regen SW in undertaking pre-application consultation in order to improve practice and ensure schemes that enter the planning system are of the highest quality possible. The protocol, written by Regen SW has received endorsement from the British Wind Energy Association (BWEA) and the south west branches of the Local Government Association and Royal Town Planning Institute.
Every wind energy developer interested in harnessing the south west's wind resource is invited to sign up to the protocol, as is every local planning authority in the south west, in order to demonstrate their commitment to effective community engagement.
The Protocol is underpinned by four key principles for effective public engagement. It includes five main commitments from developers to ensure that these principles are met, the main one being to draw up a public consultation plan in conjunction with the local planning authority. These commitments have been developed in consultation with the South West Wind Energy Developers’ Forum, and are based upon existing good practice within the industry.
In addition to the industry commitments, there are similar responsibilities that fall upon local planning authorities. By signing up to the Protocol, local planning authorities are making a commitment to support and facilitate effective public engagement. In addition to the commitments of developers and local planning authorities, there are a number of reciprocal responsibilities of other stakeholders involved in the process. The protocol is accompanied by supporting guidance to assist with the interpretation of these commitments.
To download a copy of the South West Public Engagement Protocol and Guidance for Wind Energy, click here: http://regensw.co.uk/downloads/RegenSW_289.pdf
Wind turbine capacity
It can be easy to misunderstand what the ‘capacity factor' of wind turbines actually means, and the question is often asked 'if a wind turbine's capacity factor is 33 per cent, does that mean it is only running one-third of the time?
The answer is 'no'. Wind turbines produce power over a wide range of wind speeds. They cut in at between three and four metres per second, reach their rated output at about 13 metres per second, and are regulated to produce their maximum output through to 25 metres per second, when they typically shut down to protect the drive train, gearbox and structure from potential damage*. In the UK, a wind turbine will be producing useful power for 70-85 per cent of the year, equating to 6,000-7,500 hours per year*.
However, because of the variable nature of the energy source - the power of the wind - wind turbines will not be producing electricity at full output all of the time. Therefore, a ‘capacity factor' or ‘load factor' is used. This gives the ratio of actual electricity production over what could have been produced by a plant running continuously at full capacity.
Individual wind turbines situated in the UK have a load factor of 20-40 per cent. The exact figure is dependent on location, technology, size, turbine reliability, and the wind conditions during the period of measurement. The capacity factor during the winter is therefore much higher than in the summer. In 2007, the capacity factor of on-shore wind turbines was 27.5 per cent**.
Conventional power stations, though not reliant on a variable energy source, also have a ‘load factor'. This is because there will be times when they will not be working due to maintenance, and times when they are not required due to variations in demand from consumers (from both variations throughout the day and variations throughout the year). In 2007, combined cycle-gas-turbine power stations had a load factor of 63.2 per cent, coal-fired power stations had a load factor of 62.5 per cent, and nuclear power stations had a load factor of 59.6 per cent***.
* Sustainable Development Commission (2005), ‘Wind Power in the UK'
** BERR (2008), Digest of United Kingdom Energy Statistics 2007, Table 7.4 - Capacity of, and electricity generated from, renewable sources
*** BERR (2008), Digest of United Kingdom Energy Statistics 2007, Table 5.10 - Plant loads, demand and efficiency
All above 'turbine capacity' information is taken from the FAQ section of BERR's planning renewables website. To visit the website, visit: http://www.planningrenewables.org.uk/
