Emission of the geothermal gas sulfur dioxide was at the heart of environmental issues in connection with the commissioning of the Hellisheiði Geothermal Power Plant in 2006. The geothermal gas is odorous, corrosive and, in high concentration, hazardous. Increased removal and mineralization through reinjection of the gas has accomplished to reduce emissions by three quarters. Emissions-free operations are the objective.
2010 was the first year of public health limits on atmospheric concentration of sulfur dioxide in Iceland. Then, preparations for extracting the gas, along with carbon dioxide, was already under way. A gas abatement unit was commissioned in 2014 and ever since, the capture and reinjection of the gases have gradually increased. In the bedrock, the gases mineralize; the sulfur dioxide turning into pyrite, also known as fools’ gold.
The levels of hydrogen sulfide have never exceeded regulatory limits.