Heat-seeking sheep pave way for roads that generate energy

ROADS and driveways could be turned into huge solar panels to heat houses and offices using an invention inspired by sheep on the west coast of Scotland.

An Ullapool company will tomorrow install the first road energy system in the UK in its own car park. The system takes advantage of heat absorbed by tarmac, to convert roads and other tarred areas into solar panels.

It generates energy to cool buildings and roads in summer and heat them in winter. Other benefits include not having to salt roads in winter, halving maintenance to tarmac and reducing emissions.

The idea was conceived 15 years ago while Dutchman Henk Verweijmeren was travelling between Achiltibuie and Lochinver and noticed sheep sitting on the road, which had been warmed by the sun.

Mr Verweijmeren said: "It started making me think and the idea just grew further and further."

The system, developed by Invisible Heating Systems (IHS), the firm that he set up with Liz Stewart, is used in more than 200,000sq m of motorway in the Netherlands to heat industrial units, while an airport runway heats 2,500 nearby homes.

The company markets and sells geothermal, solar and wind energy systems across Europe and has just opened an office in Birmingham. In its latest project, IHS will use the 40sqm car park to heat its 1,000sqm office and store at a cost of 12,000. According to Mr Verweijmeren, it will produce 108 megawatts of power a year, enough to heat the office three times over.

The company is also in talks to use the system for projects in Ireland and in Leeds, where it is planned to convert a disused building into flats for the homeless, using roads on either side to provide the heat. Other projects are being lined up in Scotland.

The road system works by drilling two boreholes, creating two wells, one hot and one cold. Using the heat-absorption capacity of tarmac, the energy created is stored in aquifers - underground layers of rock - which can be tapped into when required.

Excess heat absorbed during the summer can be pumped into heating systems and roads during winter. Stored cold water can be pumped into road and heating systems during summer to act as a coolant.

In winter, the water can drop to about 15C, still warm enough to keep roads frost-free and to heat industrial buildings, but a heat pump is then used to bring the temperature up to over 35C for use in offices or houses.