Technical and Economic Appraisal of Geothermal District Heating Projects in North Madrid (Spain)

Abstract

The Madrid area, located at the Northern part of the Tajo sedimentary basin, benefits from a dependable geothermal resource, evidenced thanks to previous hydrocarbon and geothermal exploration. Four (one hydrocarbon, three geothermal) deep exploratory wells enabled to assess the geoheat potential of the area. It may be summarized in terms of well deliverabilities and wellhead temperatures standing within the 200-250 m3/h; 75-90°C ranges respectively i.e. installed capacities of heat from 7 to 12 MWt depending on rejection temperatures.

Two development targets have been selected for geothermal district heating purposes which display contrasted utilization trends, wholly public (a total of twelve -educational: school, university and medical: hospital, nursing homes – buildings) and private (shopping malls, warehouses, office buildings and hotels) users respectively, which require specific technological designs and grid operating procedures, bearing in mind that retrofitting is the rule. Due to the existence of a nearby well (Geomadrid 1) whose integrity could be checked by logging, a feasibility survey concentrated on the first mentioned Cantoblanco/Valdelatas district. Its outcome proved rewarding from both technical design and economic viability stand points. As a result, the advent of the first geothermal district heating grid ever achieved in Spain could soon become a reality.