Wind Energy
Renewable forms of energy, such as wind power, are an essential part of efforts to tackle climate change and reduce the effects of its current and predicted impacts. Wind energy does not emit greenhouse gases into the atmosphere when generating electricity and therefore does not contribute to global warming and climate change, nor does it produce any dangerous waste.
The wind is an abundant and reliable energy source. The UK is the windiest country in Europe and the wind resource is much greater during the colder months of the year, when energy demand is at its highest.
Wind energy, in combination with a full range of renewable energy technologies, such as wave, tidal, hydro and solar, could meet all of our electricity needs; reducing the need for fossil fuels and the impacts of climate change in addition to improving energy security in the UK by reducing reliance on energy imports.
wIND POWER AND ELECTRICITY GENERATION
Wind energy is an indirect form of solar energy and is caused by a combination of factors including the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface and the rotation of the earth. Wind flow patterns are modified by the terrain of the earth, bodies of water and vegetation. Humans use this wind flow or kinetic energy, for many purposes such as sailing, gliding, flying a kite and even generating electricity.
The terms wind energy or wind power describe the process by which the wind is used to generate electricity, as turbines convert the kinetic energy of the wind into mechanical energy. The wind turns the blades of the rotor, which spins a shaft and gearbox in the nacelle that are connected to a generator. The generator uses an electromagnetic field to convert this mechanical energy into electrical energy.
Displacing Greenhouse Gas Emissions
Every kilowatt-hour (kWh) unit of electricity generated by wind energy displaces a kWh unit of electricity which would otherwise have been produced by a power station burning fossil fuels (coal, oil and gas).
Electricity generated from the wind does not replace electricity generated from nuclear power stations because these operate at 'base load'; that is they will be working for the whole time that they are available to supply a set amount of electricity for the National Grid.
The generation of electricity from coal, oil or gas-fired power stations produces the following greenhouse gases:
- Carbon Dioxide (CO2)
- Sulphur Dioxide (SO2)
- Nitrogen Oxide (NOx)
The release of these gas emissions into the atmosphere accelerates the greenhouse effect, causing climate change. Typically, for every kilowatt-hour (kWh) of electricity produced by the UK energy mix the following emissions are released into the atmosphere:
- 430 g of CO2
- 10 g of SO2
- 3 g of NOx
Using these figures, it is possible to calculate the displacement of greenhouse gas emissions by the generation of electricity from a wind turbine. A single 3 Megawatt (MW) wind turbine, for example, with a capacity factor of 30% (i.e. operational for 30% of the time) would displace approximately 3,390 tonnes of CO2 per year.
Measuring Carbon Dioxide Emissions
One tonne of CO2 emissions occupies 556 cubic metres (m3) of space at 25˚C and standard pressure. The volume of water in an Olympic sized swimming pool is approximately 2,500 m3. In the UK, average CO₂ emissions per capita are approximately 12.5 tonnes per year and this therefore, would be enough to fill more than two Olympic sized swimming pools.
