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GSHP: The green tech even carbon sceptics will like

Treehuggers, tightwads, patriots - it's for all of us

By Lewis Page, 13 Dec 2009

Analysis Today on the environmental front: some news that ought to please most people, for a change. The government is being urged - by its own researchers - to get behind a home energy technology which could seriously cut into both carbon emissions and (if you don't care about those) energy bills and future gas imports from Russia.

We're not talking here about rubbish like rooftop windmills, photovoltaic panels in a north-European climate, on-building slime tanks etc - nor more practical but gas-hungry schemes such as home microgeneration. No, this one is a good idea.

The scheme in question is underground heat pumps. These machines work, as their name implies, much like any other heat pump - for instance a fridge or an air conditioner. Rather than sucking heat from inside a cupboard or building and dumping it into the air around, though, this kit would suck heat from the ground and dump it into a building's hot water system.

You still need electric power, of course, but the heat energy output is generally three or four times that required to run the pumps. This makes it cheaper than burning gas to make heat, even with today's fairly low gas prices. Naturally it's a lot cheaper than using grid electricity to make heat directly - as grid electricity is often made fairly inefficiently by burning gas in power stations to begin with.

So what's the catch?

Sure enough, there is one. The network of underground pipes needed to suck heat out of the Earth means you need some land next to or beneath your home, business etc which you can dig up. Often enough, this simply isn't practical - but if it is, putting in heat pipes should be a no-brainer.

An Environment Agency report issued this week agrees, and says that the government - as opposed to subsidising idiocies such as urban windmills - should be directing money towards underground heat pumps.

“Ground source heating is a rapidly growing technology that has the potential to produce at least 30 per cent of the country’s renewable heat needs, but it needs financial support in order to grow," says the Agency's Tony Grayling.

“We would like to see this technology given adequate financial support through the new renewable heat incentive to meet its full potential in the UK."

Cheap air-con and ice for your drinks, too - it's not just for hippies

The EA report says that at the moment there are only 8000 ground source heat pump (GSHP) installations in the UK, mostly domestic units. This contrasts sharply with countries such as Sweden, where there isn't much of a gas grid and GSHP is a favourite solution.

But the Agency estimates that a future Blighty could see 1.2 million GSHPs in the best-case scenario, with 11 per cent of homes and fully 40 per cent of businesses using them.

Obviously if you're worried about CO2 powered climate change, GSHPs are a winner - their use of grid 'leccy still involves some carbon emissions, but substantially less than your probable gas or oil boiler blows out of its exhaust. Furthermore, at least some grid power is largely CO2-free - the nuclear and renewable parts - and the potential is there for all of it to be so in future. Nor are there the various issues around biofuelled heat sources of various kinds - wood from cutting down lovely trees, corpse-fat biofuel which arguably violates your status as a vegetarian (or surely as a vegan) etc.

If you couldn't give a toss about carbon emissions but wish to avoid being driven into a condition of unwashed beggary in the coming future of much higher gas prices - caused by erratic imported supplies as the North Sea plays out and/or planet-saving carbon levies - GSHPs are for you too. This also goes for any sturdy British patriots, loyal citizens of the EU or others not wishing to see their governments held to ransom by some present or future Muscovite strongman.

As a final added benefit, connection to an underground heatpipe network also offers the option of having much cheaper air-conditioning as opposed to heating - perhaps an attractive thought should global warming indeed get as warm as predicted in many quarters. (Or should your home city get bigger, increasing the "urban heat island" effect where you live; or indeed if you just like air-con.) The option might even be there in future to connect up ovens, fridges, freezers, ice-machines etc - all of them, after all, simply machines for putting heat where you want it and not where you don't - to the relevant parts of one's private heat exchange system and save even more cash.

Something for everyone there, surely. So if you've got a garden you're willing to dig up, or you're thinking of excavating your cellar anyway for extra room, or you're doing any ground-level building or surfacing of any sort - give some thought to sticking some heatpipes into the dirt. It's more or less bound to be a value-boosting bit of future proofing, though as ever the upfront costs could be a barrier.

Regarding those upfront costs, let's hope that the government sees sense and offers you a subsidy to help, since it's subsidising stuff anyway.

The Environment Agency report can be read here in pdf. ®

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