SOLAR POWER - RENEWABLE SYSTEMS AND ENERGY POWER GENERATION

The biggest source of energy in our solar system is the sun. The sun's power can be tapped in many ways, however for a green builder the main methods are solar heating and solar electricity.

Solar thermal

Solar heating systems work by placing panels consisting of metres of pipework looped around inside of them.

A vacuum tube collector is usually installed on the roof of the house and connected via a pump to a dual coil hot water tank in the airing cupboard or similar. Water or other liquids is then pumped through these panels and is heated by the sun.

This hot water can then be used around the house and is especially useful when coupled with underwater heating systems which do not require the heat a traditional radiator based system needs.

Underfloor systems can operate effectively with a water temperature of around 35 degrees, whereas over 80 degrees Celsius is required in radiated systems.

The average domestic system reduces C02 by around 350kg per year and about £40 a year of hot water bills, depending on the fuel replaced.

Solar photovoltaic (PV)

Photovoltaic (PV) solar panels convert the sun's light into electricity. The amount generated is small compared to other sources but is also completely free and can be sold back into the power grid. Solar panels are becoming more efficient each year. Building Integrated Photovoltaics (BIPV) are used in place of traditional building components such as skylights etc. These are often used in the construction of newer buildings allowing the cost of integrating them and labour to be offset.

These are proving especially popular in France where they are benefiting from government subsidies. These can take the form of roof tiles with a built in PV membrane as well as solar shingling which provides weather protection as well as energy. Solar panels are heavy so make sure that the structure can hold them and retrospective planning permission may needed. PV solar systems can in an average home installation save up to 455kg of CO2 a year (a saving of 150 - 200 GBP on electricity bills) and produce 1.5 - 3 kWh.

New technologies are in development including flexible printable (litho) solar PV converters which will reduce the cost, and provide easier installation.

Denver USA has the first muni-solar (municipal solar) installation (municipal solar) with enough power planned for 1000 homes - and the Denver county jail.

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