Geothermal Resources Offer ‘Huge Potential’ for Heating, Electricity Production

The small town of Szentlőrinc, 250 km southwest of Budapest, on the road from the city of Pecs to the Croatian border, appears unremarkable by the passing motorist. Yet, in one respect, this community of 7,000 souls is exceptional and effectively a modern-day pioneer.

By Kester Eddy

For some 900 of its homes, housing the majority of the town’s population, are heated by water sourced from a point 1,800 meters below ground. This reaches the surface just a dozen or so degrees below boiling point before entering a heat exchanger system that provides the settlement with heat and hot water. The thermal water is, meanwhile, returned via a second well to replenish the same geological layer from whence it originated.

With a heating capacity of four megawatts (MW), this project, begun in 2008 and completed in 2010, replaced a natural gas-fired district heating system and resulted in a reduction in annual greenhouse gas emissions of 26 tonnes, primarily carbon dioxide and nitrogen oxides, according to PannErgy Geothermal Power Plants, which partially owns and operates the facility.

Yet, perhaps surprisingly, Szentlőrinc is only one of 14 municipalities in Hungary utilizing geothermal energy to heat its homes and, frequently, business sites.

“We are in a basin, and the upper layer of the earth is very thin in Hungary, so we have very high heat flow, and we have a lot of water stored in the rocks [below ground], and that can be harvested,” says Gábor Molnár, managing director of Mannvit Hungary, the local subsidiary of its Icelandic parent, and the project management company responsible for the design and delivery of the Szentlőrinc plant.

‘LOW-HANGING’ HEATING FRUIT

District heating systems are the “low-hanging fruits” most readily available for conversion to geothermal heating, according to Molnár, and, partly as a consequence of sizeable urban housing schemes built in the communist era, Hungary boasts some 220 heating companies supplying 680,000 consumers, or 16% of all homes, in nearly 100 municipalities across the country.

Geothermal water resources were first explored in Hungary in 1958, but with the availability of cheap Russian gas, these were not first tapped for district heating purposes until 1987 in the town of Szentes, 150 km southeast of Budapest.

And with the expansion of geothermal heating projects, most notably in the cities of Győr (121 km west of the capital) and Debrecen (232 km east) during the past decade, these renewable sources provided some 4.7 million gigajoules