Development of the Namafjall area - Northern Iceland

Abstract

Following the discovery of rich deposits of high grade diatomite on the bottom of Lake Myvatn in northern Iceland, the Government initiated simultaneously exploration of the nearby Namafjall geothermal high temperature area and continued technical and economic feasibility study of the diatomite mining and processing. The cost of drying the relatively low cost product would have been prohibitive by use of conventional sources of heat, whereas the use of low cost geothermal steam made the operation economically feasible. A plant for processing 12,000 tons/year of refined diatomites was commissioned in late 1967, and is going to be extended to 24,000 tons/year in 1970. The discovery of down-hole temperatures in excess of 260 °C (289 °C have since been measured) aroused the interest of the main power producer in northern Iceland, who operates hydroelectric plants in the neighbourhood, for building the first pilot geothermal power station in Iceland (3 MW atmospheric exhaust), commissioned in early 1969. A geothermal district heating system for the village being built for plant operators is presently being planned. The paper will give a short description of the geology of the Namafjall hydrothermal system which is now considered to comprise perhaps 50 km 2. The drilling operations will be described, as well as the wellhead equipment, steam transmission system, which may be subject to −30°C ambient temperatures. The design of the power station will also be reported on. Capital costs, steam price and generation costs will be given. The paper may further discuss some problems relating to the improvement of future energy utilization within this unusually varied geothermal development.