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Last Updated: Tuesday, 21 October, 2003, 09:56 GMT 10:56 UK
Turn your home into a mini power station
As autumn sends a chill down the spine, heating one's house doesn't have to hurt the environment. Technological advances have given us a range of innovations for turning the humble home into a mini-power station.

This summer millions of people were made to think hard about something they had always taken for granted - electricity.

The massive power cuts in Italy, Canada and the US, coupled with notable outages in London and the West Midlands, wrought chaos and confusion.

Some experts say more are to come, as utilities companies try to square pressure on overheads with increased consumer demand.

Even when the power is flowing, all is not as it should be. A report on Monday highlighted how some suppliers are being double-handed with our money, demanding cash when they want it, dragging their feet when they owe it to us.

Britain is commited to seeing more electricity generated from renewables (such as solar power, above)
Government grants are available to soften the cost of installing renewable energy systems
Yet it does not have to be like this. Gradually more homeowners are turning their properties into mini-power stations, generating much of the electricity they need on-site.

What's more, the trend for "micro-generation" tends to draw on renewable energy sources, rather than environmentally-damaging fossil fuels. Unused power is simply sold back to the National Grid.

A conference in London on Tuesday will examine how home builders can take advantage of this new technology. Increasingly, however, micro-generation can be incorporated into existing homes, and within a few years even a typical three-up-two-down might benefit from what's offer.

So what are the options?

GEOTHERMAL ENERGY
What is it? Think of the Earth as a giant storage heater, absorbing heat from the sun during the summer. A few metres below the surface, the soil maintains a constant temperature of 11-12°Celsius in the UK. By feeding a coil into the ground and pumping water through it, the Earth doubles up as central heating boiler.

So-called geothermal systems offer "very considerable savings," on heating bills, says Andy Moore, of Penwith Housing Association in Cornwall. After a successful trial, it has started "retro-fitting" them in sheltered housing for old people.

Pros: Cheap to run, you just pay for the running of the pump.
Cons: Fitting is disruptive (it can mean drilling a hole up to 50 meters) and expensive - £10,000 per property.

The panels are on the middle roof
Not a typical power station: Solar panel can be discreet
PHOTOVOLTAIC (PV) CELLS
What is it? Converts the sun's radiation into electricity. One of three different sorts of solar energy technology, PV is the most expensive but potentially the easiest to manage and maintain.

Pros: Cell panels are easy to install and can be fitted on top of a normal roof. Panels covering 10-15 sq m would produce about a third of an average family's electricity.
Cons: An expensive option (£8,000 - £18,000) although grants are available, as with most of these systems. While cost has come down, it's unlikely to fall much further, says Andreas Biermann, of the Energy Saving Trust. Might save about £100 per year on electricity bills. Can be unsightly, although latest innovation is to combine cells into slate tiles.

MICRO-WIND POWER
What is it? A wind turbine (modern-day windmill) which has rotors fitted with aerodynamic blades, attached to a generator. Britain has 40% of Europe's total wind energy resource, so lots of potential.

Pros: Cheaper than solar cells and there's plenty of wind around the shores.
Cons: Impractical for built-up areas - wind speed increases with height, so best suited to properties with a lot of land.

Just around the corner - micro-CHPs will be available from December
MICRO-CHP
What is it? If you believe the hype in the industry, this is the impending revolution. Although not strictly a renewable heating source its trick is to convert the heat given off by a conventional gas boiler into electricity.

The size of a washing machine, a micro-CHP houses a typical boiler plus the clever conversion kit. Early models - they will go on sale in December - will suit a large family house, says Andreas Biermann. More compact units are expected to follow.

Pros: Straight-forward installation and the unit is reasonably unobtrusive. Could save a typical family £150-£200/year on electricity.
Cons: Fairly expensive - initially about £2,000 each. New technology, so may need refining, although Mr Biermann says much work has already gone into perfecting reliability.

OTHER OPTIONS
Micro-hydro power - harnessing the power of running water - dates back to ancient times, but recent advances have made it viable for use in properties with only a small natural water supply.

Biomass is the burning of sustainable fuels, such as wood chips, grasses, crops and animal manure. Unlike fossil fuels, the CO2 generated in the burning is off-set by that absorbed during the fuel's growth. It is however, fairly impractical for town and city dwellers.

Clearly, the prospect of a typical house turning itself into a mini-power station is still some years off. Even with the grants on offer prices will have to fall to bring these options into the bugets of most household. Meanwhile however, the big power suppliers are starting to plug into their own renewable sources and pass on the benefits to customers.


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