Contract No. GE/031/95/AT

Fernwaerme Haag supplies the community of Haag am Hausruck with room heating, using the water from a geothermal well directly as the heat-transporting medium within a local heating grid.

Transfer of heat to individual houses is via heat exchangers. Dispensing with a heat exchanger at the heat source should reduce the temperature spread between source and return, and therefore improve the effectiveness of the heat recovery.

The total heating requirement for Haag with its 310 houses and nearby apartment and hotel complex is about 12,000 kW. It is hoped to achieve a connected supply of 5,000 kW by 1999, and to supply a neighbouring community with 1,500 kW. The plant went into full operation in 1996 and currently supplies 80 households, all public buildings and a hotel complex with 140 apartments.

Renovating existing geothermal systems is often a cost-effective and efficient way of extracting more energy from a geothermal resource. In this project, a new geothermal well will be drilled, and will be used in conjunction with an older well.


The Melun l'Almont plant in operation.

Melun l'Almont is the oldest geothermal site of its type in Europe. The existing system was constructed in 1968-69, so the well has now reached the end of its useful life and needs to be replaced.

The new system uses a well of alarger diameter (17" instead of 12") with a larger casing (13 3/8" instead of 9 5/8"). It is built with a steel casing and composite epoxy tubing (preventing corrosion and deposits) which will be used in conjunction with the existing well. The technology used in the new type of well allows continuous monitoring of its state and performance. This new design is better both environmentally and operationally, but will have very little effect on the overall economics and energy costs of the project.

Heat from the well is used by the city of Melun (9,000 inhabitants) and is estimated to save approximately 90,000 tonnes of oil throughout its life, with a payback period of 20 years.