Outside Spaces: Renewables

ABOVE: Mount the Power Predictor on site and it will forecast how long it will take to recover the costs of installing renewable energy equipment. It also recommends the most cost-effective form of renewable energy and the most appropriate manufacturers. powerpredictor.com.

How about generating your own green electricity? Unsurprisingly there has been a huge growth in interest in this field amongst the self-build community, and this is set to expand dramatically now that Feed-in- Tariffs (FiTs) are due to be launched in April 2010. Feed-in-Tariffs guarantee you a premium rate for any electricity you export to the grid, thus greatly reducing payback periods. Indeed, it is anticipated that exporting renewable energy may become a profit centre for the householder.

There are two main technologies suitable for home-brewed electricity:

Photovoltaics: Solar arrays, which are usually roof mounted, generate electricity in daylight. They have a fairly high installation cost – typically around £1,000 per m² – and the amounts of electricity produced are not that large — typically 100kWh/m²/annum. The electricity produced is DC and it needs to be converted to AC for use in the home and for export to the grid. This is done by way of an inverter and a two-way meter. You need a south-facing aspect for the installation to make sense. There are many different systems on the market, including versions that integrate with roof tiles, so that you don’t end up with a separate panel on top of a new roof.

Wind Turbines: These come in many shapes and sizes and, invariably, the larger the turbine the better the performance. The small, roof-mounted ones have proved to be very disappointing but 6kW wind turbines, mounted on a pole, can deliver up to 5,000kWh/annum for a cost of around £20,000. Again, the system needs an inverter to transform the current, and a two-way export meter. The success (or otherwise) of wind turbines is incredibly location-sensitive: you need good average wind speeds, and a site which is not affected by nearby buildings or trees — ideally somewhere out in the wilds.

"We Harnessed the Sun to Power Our Home"

Richard and Sian Liwicki’s new Oxfordshire farmhouse uses solar heating and hot water

Richard and Sian used the sun in every way imaginable to heat and power their new home, built on the site of a vineyard. On a design level, the couple incorporated as much passive solar gain as possible, installing a double-height conservatory, which faces south to make the most of the light and warmth from the sun. “Even before you start using new technologies like solar panels it’s important to site a house correctly,” says Sian. “We also have a massive curved blockwork wall in the conservatory which is rendered in clay and acts like a radiator, absorbing heat and releasing it slowly.”

Solar panels on the slate roof warm the family’s water, PV cells generate electricity from the sun, and a weather station has been installed to monitor and measure changes in the internal and external environment.
Read more about this self-build

Further reading:

• Outside Spaces: Driveways, Garages & Outbuildings
• Outside Spaces: Landscaping & Boundaries
• How to Save Energy in Your New Home

Return to 'The 12 Steps of Self Build: Outside Spaces'