Green energy
The UK has a target to source 15% of its energy from renewable sources by 2020
Green, or renewable, energy is generated by wind, sun and sea, or by burning replaceable sources such as waste products and crops (biofuels).
The most prevalent sources of renewable energy in the UK are biofuels, wind and water. Unlike fossil fuels, these will never run out and don't release extra CO2 into the atmosphere.
The government's Renewable Energy Strategy sets out plans to radically increase the use of renewable electricity, heat and transport fuels to fulfill European targets for renewable energy use. As part of these targets, 15% of our energy should come from renewable sources by 2020 - a seven-fold increase on current levels.
Generating green energy
More than two-thirds of our future renewable energy could come from onshore and offshore wind power, but there could also be important contributions from hydro, sustainable bioenergy, marine sources and small-scale technologies.
Today, all energy suppliers have an obligation to source an annually increasing percentage of their electricity from renewable sources. The Renewables Obligation is the government's main way of supporting the development of renewable electricity. The current level energy suppliers must source is 9.7% for 2009/10, rising to 15.4% by 2015/16.
How do I switch to a green energy supplier?
Most gas and electricity companies in the UK offer green energy tariffs. Green suppliers or tariffs make a contribution to environmental schemes but don't necessarily guarantee the energy you are supplied with comes directly from renewable sources. You can find out about different types of green energy tariffs in our understanding energy tariffs guide.
Other energy companies, such as Good Energy and Green Energy UK, specialise in providing up to 100% of energy directly from renewable sources.
You can search for green energy tariffs and companies using Which? Switch. You can order your results in order of price or fuel mix – this lists results in order of the amount of renewable energy each uses.
You can check the fuel mix for each energy supplier in our energy suppliers section.
Does green renewable energy cost more?
Green energy tariffs do cost more than the cheapest non-green options but if you're concerned about the environmental impact of the energy you use you may feel this is a price worth paying. Green energy costs more because green energy suppliers incur additional costs in producing renewable energy, offsetting carbon emissions, investing in renewable energy or donating to green funds that invest in new green technology, or other environmental schemes.
Types of green energy
Wind power
The UK has some of the best wind resources in Europe
The power of the wind is harnessed by wind turbines which drive generators and create electricity. The UK is the windiest country in Europe, and as such has the biggest potential wind energy resource in Europe. Wind farms can be built both onshore and offshore and are one of the most developed and cost-effective renewable energy technologies.
Wind power is plentiful, renewable and reduces greenhouse gas emissions when used instead of electricity generated from fossil fuels. Wind power is the world's fastest growing renewable energy sector, and in the UK it has overtaken hydropower to become the largest renewable generation source. Onshore wind farms make up the majority of this.
In May 2009, energy supplier Eon announced plans to begin building the largest off-shore wind farm in the world off the Kent coast. The wind farm will power 750,000 homes and could be generating power in time for the 2012 Olympics.
The government says more than two-thirds of future renewable energy could come from on and offshore wind farms.
Marine power
The government expects wave and tidal power to help supply the UK's longer term (2020-2050) energy needs and meet renewables targets by providing up to 20% of our electricity needs. However, further investment is needed for wave and tidal power to make a significant contribution to the UK's energy supply.
A number of different systems have been developed to harness the power of waves and tides. These include:
- Tidal impoundment - water travelling through tidal estuaries drive turbines built into the bed of the estuary. There are a number of sites in the UK suitable for this technology and existing impoundments include Cardiff Bay, Tees Barrage and the Thames Barrier. There are environmental concerns about tidal impoundment as these structures impact on the ecology and physical characteristics of estuaries.
- Submerged turbines - these tidal systems are mounted underwater in seas or estuaries. They are generally believed to have less effect on the natural environment, but installation and maintenance is more difficult.
- Wave energy generation - generating electricity using the power of waves has great potential. The UK's extensive coastline and engineering expertise means marine power is capable of generating vast amounts of electrical energy at scales comparable with wind power. Scotland is home to the world's largest shoreline wave power plant.
In September 2009 the government launched the Marine Renewables Proving Fund, inviting wave and tidal energy developers to bid for £22 million in new grants designed to speed up commercial development of marine energy technologies.
Biomass
Tree matter can be burnt in stoves, boilers or dedicated biomass power stations
Biomass refers to a group of materials derived from plants and living organisms that can be used to generate heat or power. These materials tend to fall in to three main groups
- Tree matter and plant residue from sustainable woodlands. These materials can be burnt directly in stoves, boilers or dedicated biomass power stations.
- 'Woody' crops grown specifically for energy or agricultural residue. These crops are harvested and burnt in stoves, boilers or dedicated biomass power stations. There are concerns that energy crops compete for land used for food production. Research is currently being carried out into the social, economic, environmental and land use effects of biomass for heat and electricity to minimise its future impact on the environment and food production.
- Biodegradable waste and residue such as sewage sludge, animal manure, chicken litter, waste wood from construction and food waste. These materials produce 'biogas' when they break down. Biogas can be collected and used in an engine or turbine to generate electricity, or used to provide heat
The government's consultation on its Renewable Energy Strategy estimates around 30% of the UK’s overall 15% renewable energy target could come from biomass heat and electricity in 2020.
Hydro power
About 1.3% of the UK's electricity comes from hydroelectric schemes
Hydroelectricity is generated from the power of flowing water. Hydro power can be generated using rivers or man-made water systems, where water flows from a high-level reservoir down through a tunnel and away from a dam. Turbines placed within the flow of water extract its kinetic energy and convert it to mechanical energy.
Hydroelectric energy uses proven and efficient technology. Modern hydroelectric plants have energy conversion efficiencies of 90% and above.
The UK currently generates about 1.3% of its electricity from hydroelectric schemes - most of which are large-scale schemes in the Scottish Highlands. There's limited scope for expanding hydroelectricity production in the future due to environmental concerns and because many of the most suitable sites for hydroelectric schemes have already been used.
Waste incineration and landfill gas
Energy can be created from waste - either by burning waste using incinerators or collecting landfill biogas emitted when waste decomposes in landfill sites.
- Generating renewable energy from burning waste could greatly reduce the amount of waste that is sent to landfill in the UK. However, some environmentalists argue this practice disturbs local habitats and causes local air pollution.
- Landfill or 'biogas' gas is mostly made up of methane and carbon dioxide and is formed when biodegradable waste breaks down within a landfill site. It can be collected and used in an engine or turbine to generate electricity, or used to provide heat for industrial processes near the landfill site. The government expects the amount of energy generated from landfill gas to fall over time as available landfill sites are used up. However, if all food and wood waste currently sent to landfill was used for energy it would fulfill approximately 18% of the UK's renewable energy target.
Solar power
Solar panels are most often used as part of a microgeneration system
In a single hour the sun transmits more energy to the earth's surface than the world uses in a year.
Solar power systems harness the power of the sun using solar panels or 'collectors' to create electricity or heat water.
There are two key types of solar power: solar water heating panels that heat water for use around the home and photovoltaic (PV) solar panels which generate electricity.
In the UK solar power collectors are usually used as a microgeneration system to create electricity or hot water for individual homes or offices. You can find out more about installing solar panels in our guide to buying solar panels.
It's estimated that 12% of our heat could come from sustainable biomass, biogas, solar and heat pumps, supplying the equivalent of four million households with their current heating demands.
Cut your energy bills
Those switching energy suppliers using Which? Switch between 1 January and 21 October 2009 saved an annual average of £263.
Why wait to start saving? Compare gas and electricity tariffs now to find the best energy deal for you.