Barrett Byrd Associates

Foundation specialist Roger Bullivant Ltd is drilling deep into the ground to tap into natural stores of heat and provide warmth for new homes, reports Mike Walter

Central heating systems in modern houses all around the country could soon make use of the earth’s natural stores of heat buried deep underground. Roger Bullivant Ltd (RBL) has developed a method of drilling to a depth of 30m and has entered into a new joint venture to provide house builders with a complete geothermal heating service.

RBL has teamed up with heat pump specialist ECR and storage cylinder supplier Gledhills to form Geothermal Heating & Cooling Systems Ltd (GHCS). Use of the company’s service will allow house builders to meet renewable energy targets and help the Government to meet its commitments to halting climate change.

"Geothermal heating has been around for some time, but traditionally it has been too expensive and there have been insufficient incentives for house builders to install such systems," says Paul Smollett from GHCS. "We have found a way of making the technique less costly and new building regulations designed to reduce energy consumption will come into force next year. This and a system of environmental tax credits are encouraging house builders to investigate renewable sources of energy for central heating.”

Geothermal heating systems take on a variety of different forms, but generally involve pumping fluids down into the ground through heat transfer tubes and then back up to hot water storage cylinders in order to provide central heating. RBL’s drilling technique is, according to Smollett, dramatically reducing the cost of installing a geothermal hole down to 30m where the ground is warm enough to heat a house.

The method involves augering out a hole in the ground using a hollow drilling head and a 'string', which allows coiled tubing to be passed down into the hole while the drill string is still in place and supporting the surrounding ground. After the tubing is fed into the hole, a bentonite grout mix is pumped through the drill string, which is then removed and the hole topped up with grout. RBL estimates it will have installed Geothermal Heating & Cooling systems for 60 houses by the end of this year. “Our technique is reducing the time and costs involved in the process and makes geothermal heating a genuine alternative to fossil fueled heat,” he adds.

The new geothermal heating system was installed for the first time this autumn on behalf of Barratt Homes on a handful of properties at Buckshaw Village – a huge new development of 2,000 homes under construction on a former Royal Ordnance factory site near Leyland in Lancashire.

"Geothermal heating is very efficient. We have calculated that for a typical four bedroom house, it will reduce heating bills by up to two thirds each year," says Smollett. "Geothermal heating is also very reliable because it has very few moving parts. Systems installed in the United States 15 years ago have not required any maintenance."

Next April, a revision to Part L of the building regulations is expected to come into force. Heating of all new houses built from that date must be made 22-25% more efficient, either by greatly increasing insulation or by using renewable sources of energy.

"House builders are entitled to receive a tax credit for use of green energy through the Enhanced Capital Allowance scheme which is making it economically possible to install between one and three geothermal holes per house. This amount of geothermal heating produces a 30% reduction in use of fossil fuel," Smollett says.

The 2003 Energy White Paper committed the Government to a 60% reduction in carbon dioxide emissions by 2050 and the Office of the Deputy Prime Minister's Housing Growth Plan has pledged 300,000 new homes in four growth areas. "We believe that geothermal heating can help the Government to meet both of these aims," adds Smollett.

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