CO2 emissions from geothermal power plants and natural geothermal activity in Iceland

The ratio of CO2 emissions from power plants to natural emissions is a measure of the environmental impact associated with geothermal power production. Emissions from Icelandic geothermal power plants amounted to 1.6 × 108 kg year−1 in 2002. Two independent estimates of natural CO2 emissions range between 1 × 108 and 2 × 109 kg year−1. Thus, power plant emissions are significant compared to estimated total emissions (i.e., not less than 8-16%). However, direct CO2 flux measurements from four of the approximately 40 geothermal/volcanic systems in the country amounted to 3 × 108 kg year−1, indicating that these estimates of the total natural flux may be too low.