Sunday, 21 March 2010

Considering renewables?

If you've done the basic things to stop wasting energy at home, such as installing loft and wall insulation and energy efficient lighting and appliances, then you might want to consider installing your own renewable energy technologies.

Working out which technology is most suitable for your home is a good way to start. The Energy Saving Trust has an online questionnaire to help make that decision here.

Wind turbines

Wind turbines are the iconic renewable energy technology. At home, small turbines are only suitable in certain parts of the country, if they have clear sightlines away from other buildings or trees and where there is a wind speed of no less than 5 m/s. Be aware that, in some areas, erecting a turbine will also need planning permission. You can see if your home is suitable for wind power at the Energy Saving Trust website.

Solar power

Despite a distinct lack of sunshine in many parts of the country, the UK is quite well suited to solar power. As contrary to popular belief solar photovoltaic (PV) cells don't need direct sunlight to work, so you can still generate some electricity on a cloudy day.

Solar PV panels convert sunlight directly into electricity. In addition to Solar PV there are also solar water heating systems that use the sun's heat to warm up water, which can then be used directly. Both are best placed on south-facing roofs but other orientations can also work, though less efficiently. You can find out here if your home is suitable for solar power.

Solar systems are no doubt useful for cutting your energy use – but they can be expensive. A full set of PV panels can cost upwards of £10,000 and solar thermal systems around £4,300.

Feed-in Tariffs (FITs) will be introduced to Great Britain on 1 April 2010. The scheme requires energy suppliers to make regular payments to householders and communities who generate their own electricity from renewable or low carbon sources such as solar electricity (PV) panels or wind turbines.

The scheme guarantees a minimum payment for all electricity generated by the system, as well as a separate payment for the electricity exported to the grid. These payments are in addition to the bill savings made by using the electricity generated on-site.

From April this year, every unit of electricity generated at home could earn up to 41.3p for a PV system – which could mean around £800 per year for a typical-sized solar electricity installation. Find out more about Feed-in Tariffs here.

Other technologies, such as wind, hydroelectricity and micro combined heat and power, will also benefit from the scheme, though with smaller payments than solar PV.

Air and ground source heat pumps

A ground source heat pump uses pipes buried underground (usually in a back garden) to extract heat from the ground and warm water for radiators in a home. A typical system costs around £12,000, with running costs of around £650 per year where the heat pump provides all heating and hot water. They can save around 540kg of carbon dioxide (CO2) and £160 a year if they replace an oil-fired central heating system, or more if replacing coal or electric heating.

Air source heat pumps extract heat from external air in the same way that a fridge extracts heat from its inside and these systems can operate with outside temperatures as low as -15C. They are cheaper than ground source heat pumps to install, – £5,000 to £9,000 – but are not always as efficient with running costs for heating and hot water at around £790 per year. The Energy Saving Trust says that the system could save up to 5,000 kg of CO2 and £700 per year if it replaced an electric heating system.

Wood fuelled heating

A stove burning logs or pellets could heat up a single room or, for full home use, a wood fuelled boiler can replace your current boiler/heating system. Because the boiler uses wood, it will only release the CO2 that was absorbed as the tree was growing in the first place. If the wood has been sourced responsibly and new plants are grown to replace the ones chopped down to make the fuel, wood fuelled systems are essentially carbon neutral.

A standalone stove costs around £3,000, while a typical automatically-fed boiler would set you back around £9,000. But wood fuel systems can save up to 9,600 kg of CO2 per year if they replace a coal-fired system.


Finally, there is small-scale hydroelectricity. These use running water to turn a turbine that generates electricity. The faster the water flows and the more water there is, the more electricity can be produced. Clearly only suitable for people with a stream nearby, the advantage of this technology is that it is also eligible for the government's feed-in tariff. You can find out if your home is suitable at the .


There are grants available for heat generating technologies such as wood fuelled boilers, air and ground source heat pumps and solar water heating from the Low Carbon Buildings Programme, which you can find out about by using the Energy Saving Trust handy online guide. Bear in mind that, to qualify for any of this, you need to have already made the basic steps to make your home more energy efficient, such as insulation and draught-proofing.

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