Air moves around the Earth because of the differences in temperature and atmospheric pressure that exist. Wind turbines harness the movement of air to produce energy. The wind turns the blades which turn a rotor shaft; the resultant mechanical power is used to drive an electricity generator. Wind turbines are often grouped together in wind farms.
Wind power has very promising potential in the UK as we live in the path of Atlantic depressions (low-pressure systems), which bring windy weather. The UK currently has over 70 onshore wind farms and it is thought that wind power could be supplying 10% of the UK’s electricity by the year 2025.
Wind farms provide a clean source of energy, but they do have some disadvantages. To some, they have a detrimental visual impact, and can be noisy in windy conditions. Suitable locations for wind farms are often in areas of scenic beauty and so careful consideration needs to be given before they can be built.
It is estimated that the UK has a very large offshore wind resource. Increasingly, it is now becoming financially viable to build offshore wind farms. Currently there are 13 ofshore windfarm in UK waters, most off the coasts of East Anglia, Lancashire and Cumbria.
Solar power is the term used to describe energy derived directly from the Sun. The Sun provides the basis of energy for all living things. Sunlight has been utilised by humans for drying crops, and heating water and buildings for millions of years. Solar energy is free and will never run out. We can use solar panels to turn the Sun’s energy into useful energy. There are a number of different ways that we can utilise the Sun’s energy.
Passive solar heating
Houses can be designed with large windows in the south facing
walls and small windows in the north facing walls. This would allow natural light and heat from the Sun to be used to its full potential and reduce the need for electricity.
Active solar heating
Solar power can be used to heat large
bodies of water mainly for domestic hot water systems, but also swimming pools
Photovoltaics allow the direct conversion of solar radiation into an electric current by the interaction of light with the electrons in a semiconductor cell. As development in solar technology has increased, it has become much cheaper and the UK is starting to invest in the technology.
This is the term used to describe plant material and animal waste, which can be burnt to produce energy. In terms of energy production, “biomass” refers to using tree and grass crops, and forestry, agricultural, and urban waste. It is the oldest source of renewable energy known to humans. Biomass is considered to be a renewable energy source because the energy it contains comes from the Sun.
Unlike other renewables, biomass energy does release carbon dioxide, but it is only returning to the atmosphere as much as was removed through photosynthesis during the plant’s lifetime. Burning fossil fuels, by contrast, returns carbon dioxide to the atmosphere that has been locked away in the Earth’s crust for millions of years.
Crops can be grown with the purpose of being burnt to produce energy, e.g. willow and oil seed. We can also extract methane from waste landfill sites and burn it to generate electricity. Methane is a powerful greenhouse gas, and burning it would help to reduce the amount of methane in the atmosphere.