Renewable Energy
Renewable Energy? Is it the answer? It may not be the total solution but it has a huge part to play in supplying the energy needs of the planet in the future. After all, oil, gas and coal were all formed, over many millions of years, as a bi-product of solar energy. The sun's light (which results from the nuclear fusion of hydrogen into helium) is responsible for most forms of energy found on the planet, and is estimated to be 10,000 greater than man's current energy needs. The sun's heat energy produces wind, waves (from wind), ocean currents and hydropower (through the hydrological cycle) and the sun's light energy drives the growth of plants through photosynthesis thus providing wood and other biomass.
We find ourselves in an age, where the bi-products of solar radiation over millions of years i.e. oil, gas and coal, are starting to run out and so we need to use the solar radiation of today to satisfy our energy needs and this is where the products and systems that capture some that 174,000 terawatts (big number! Add 12 noughts) come into play.
So what are the options?
Solar hot water panels. Very simply they capture the light from the sun and transfer this heat into a useable form such as hot water. Most properties that have available south facing roofs are suitable. Once installed they require very little maintenance and will keep working for 30-35 years. Really only suitable for hot water systems that have a hot water cylinder (although now possible to get combination boilers that accept pre-heated hot water). Over a year they will contribute up to 70% of your hot water needs. Payback can be as little as 8 years. See the grant/feed-in-tariff page for further information.
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Solar photovoltaic panels. Again they capture the light from the sun and convert this into electricity. A standard panel is about 1.4 sq meters and will be rated at 160-200 watts. A standard 180 watt panel will produce approx 144 kW hours in a year (in the UK). If you have the space get ten panels together and they will produce over 1400 kWh over the year (approx 40% of the electrical needs of an average house). With the introduction of the feed-in-tariff scheme electricity produced by pv panels can be worth up to 44.3 p/kWh dramatically bringing down the payback period.
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Heat pumps. Discussed in length on the heat pump page but simply put they use renewable energy stored in the ground and by means of heat exchangers and compressors convert this energy into useable heat. They work best with under floor heating which can heat your home with water at only 30-35 degrees C. The more thermally efficient your house is the better they work. Great for new build and some older properties. They are more expensive to install than conventional boilers but will be cheaper to run (up to 70% in some cases) over the year. Don't put a heat pump into a thermally inefficient house that has radiators that were designed for water at 80 degrees. It will be expensive to run and might cost more than oil or gas. The economics of heat pumps has changed dramatically (for the better) with the introduction of the Renewable Heat Incentive in April 2011.
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Wind turbines. Location, location, location! A badly sited turbine will not work. The secret is getting the turbine up into clean air (i.e. no turbulence) and sitting it where the average wind speed is greatest. There are a range of wind turbines rated from 600 watts up to 15kW suitable for domestic and commercial use. A 1.5kW turbine correctly suited will produce up to 2,000 kW hours p.a. and a large 15 kW turbine will produce up to 30,000 kW hours p.a. The larger the turbine blade the more efficient the turbine will be so the general rule is to go for as large a turbine as the location and your budget will allow. Wind turbines are now benfitting from the feed-in-tariff scheme as from 1st April 2010. See the grants page for further information
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Biomass. Think wood fires, wood or wood-chip or pellet stoves, large boiler systems running off logs or other biomass. There is a huge range of fires, stoves and boilers available from the small 2 kW log burning stoves suitable for top-up heating in say a hallway to the large 20 kW and upwards boilers that can heat a large house or building and supply hot water. A truly renewable heating choice that is also very satisfactory to run and look at. Be aware of how much hands-on time some of them require and how hungry they can be!
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