Orly Airport, one of the two big airports serving Paris, is to extract geothermal energy from deep underground to slash its heating bills, the facility's owners said.

Two shafts each 1,700 metres (one mile) deep will be drilled on the airport's perimeter to access a water table warmed by heat emanating from the Earth's hot core.

Drawn upwards by natural pressure, the water will emerge at the surface at 74 degrees Celsius (165 degrees Fahrenheit) and then be injected into the airport's heating system. It will then be pumped back into the ground at a temperature of 45 C (113 F).

"We have the unprecedented luck of having hot water below our feet that can heat a large part of Orly without CO2 [carbon dioxide] emissions. We are the first airport in Europe to do this," Pierre Graff, who is chairman and managing director of Aeroports de Paris (ADP), said on Wednesday.

The project, launched after a technical and financial feasibility study, will cost 11 million euros (17.27 million dollars). The Orly-Ouest terminal, part of Orly-South, the airport's Hilton Hotel, and two business districts will be hooked up to the system from 2011.

ADP hopes geothermal will meet a third of its heating needs and coincidentally save 7,000 tonnes of its 20,000 tonnes of its annual emissions of CO2, the principal greenhouse gas.

The neighbouring towns of Orly, located south of Paris, and l'Hay-les-Roses, already use geothermal.