The Reykjanes Seawater Geothermal System – Its exploitation under regulatory constraints

Abstract

The Reykjanes high enthalpy geothermal system is located at the tip of the Reykjanes peninsula were the mid-Atlantic Ridge comes ashore in southwest Iceland. Its geothermal fluid has seawater salinity and originates from the seawater source underneath the peninsula. The first research drillings were made in the sixties and limited (50 kg/s) production was from the system in the eighties for a chemical plant. In 1998 research and preparation for a 100 MW generating power plant started and the plant came on line in May 2006. Now an enlargement of the power plant to 150 MW is underway that could be on line in 2011.
The general properties of seawater geothermal systems are addressed with reference to regular water systems. The high production impact (800 kg/s) in the beginning of operation is described and how it has affected the system. As environmental and other regulatory agencies have intermixed “sustainable development” with sustainable production and resource conservation, additional constrains are set on the production. To comply with these constrains the production strategy needs to be reevaluated and possibly changed. First steps in that direction have been taken with drilling into a high pressure steam zone (>55 bar) that is developing in the system. Finally, the future forecasts and goals are discussed.