Geothermal in Netherlands

Geothermal heat is obviating the need to use 3 million m3  of natural gas. A second borehole was started in late-2008 in preparation for a doubling in the size of the greenhouses. It is expected that this application will encourage further use by horticulturists. TNO, a Dutch research institute under contract to the Ministry of Economic Affairs, is currently mapping the deep heat resource in order to reassess the potential of the Netherlands.

Analysis of deeper formations may demonstrate the feasibility of the resource for electricity generation. Originally the object of drilling energy wells in the country was to store solar energy for space heating in winter. Later, this application broadened to the storage of thermal energy (both heat and cold) from other sources and to include geothermal heat pumps. The R&D of the early applications in the 1980s was focused on large scale applications such as commercial buildings rather than residential houses. Almost all of these early projects used ground water wells to store and extract thermal energy. In the late 1990s, borehole heat exchangers began to pay a more important role with geothermal heat pumps.

At present, most of the geothermal heat pumps projects are using vertical borehole heat exchangers, with over 10,000 of these in operation. Most are small scale applications such as for single family houses or small office and commercial buildings. Systems in family homes are designed for the heating load, whereas in commercial/office building the design is for both heating and cooling. Most projects use aquifer storage for both heating and cooling, with heat pump capacities in the 50 to 100 kWt range, and using ground water flow rates at less than 10 m3/hr (as no permits are need up to this rate). In Amsterdam about 1,200 large systems are installed with heat pump capacities around 1,000 kWt in some cases extracting over 250 m3/hr from a single well. Direct groundwater cooling is also practiced with the larger projects.