Sustainable use of geothermal energy in Icelandic horticulture

• Main Authors: Björn Gunnlaugsson, Magnus A. Agustsson, Sveinn Adalsteinsson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: geothermal energy; greenhouse; horticulture; heating; disinfection; soil; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.612.3672; http://www.jardhitafelag.is/media/PDF/S14Paper071.pdf

The greenhouse industry in Iceland is based on abundant geothermal energy in form of steam or hot water. The annual use of geothermal energy in greenhouses is approx. 216 GWh/yr that accounts for 80 % of the geothermal and hydroelectric energy used in horticulture. Other uses of geothermal energy are soil disinfection, 6 GWh/yr and soil heating in the cultivation of field vegetables, 15 GWh/yr. Artificial light has become an integral part of production in greenhouses to increase yield during the dark winter months. Cut flowers are now produced year-round with artificial light and this application is expected to increase substantially in vegetable production in the next decade. High-pressure sodium lamps, which are used for lighting, produce a lot of energy as heat that will partly substitute geothermal energy as a source for heating of the greenhouse, i.e. if no new lamp types will become available. Better cultivation techniques will also give more yield pr. m2 resulting in a decreased greenhouse area. The estimated use of geothermal energy for heating greenhouses will therefore only be 114 GWh/yr in year 2011 that is approximately 60 % of total geothermal and hydroelectric use in horticulture. No major changes in usage of geothermal energy for soil disinfection or soil heating in field vegetables are expected in this period. Soil heating in sports fields might increase in the next decade resulting in an annual use of 20 GWh/yr.