Geothermal energy emissions of little concern

Alexander Richter 30 May 2009

In a recent news item labelled “Geothermal is not so clean” on IPS News (link), a very single-minded view and simply wrong picture on the geothermal power plant of Hellisheiði in proximity to Iceland’s capital Reykjavik is given.

The story, which has been published by various other news services, gets very critical responses from various players in the industry, industry associations and the owner of the plant, Reykjavik Energy.

The utility replied quickly this week with a statement answering some of the accusations made in the article.

“In a serious way, Reykjavik Energy’s operations are slandered by unattributed, unsubstantiated and, on several occasions, not in compliance with scientific findings. In no way was Reykjavik Energy contacted by the reporter for confirmation or rebuttal of statements the story comprises. Reykjavik Energy has utilized geothermal energy for house-heating in Reykjavik for 80 years, thus saving CO2 emissions of 100 million metric tons. Annually, these savings equal the total current CO2 emissions of Iceland. The geothermal water is also conducted to people’s taps. Because it contains H2S in low concentration, the smell is familiar to this nation and its effects, i.e. on silverware. The connection made in the article between increased airborne H2S and the need for more frequent silver-polishing is unsubstantiated and highly speculative.

H2S emissions have increased in line with increased geothermal utilization. Certain weather conditions in the wintertime have led to higher levels of H2S in the capital area. Since our noses are very sensitive to H2S, they work as best of analytical sensors for the gas. The story correctly states that the highest 24-hour level measured in Reykjavik was 150 microgram per cubic meter. This level is 1/100 of the level allowed for a working place for an eight hour working day for a lifetime. As correctly stated in the article, the peaks measured in Reykjavik, present no health problems to inhabitants.

The sulfur contents of the geothermal emissions have twofold effect on vegetation. In Iceland, where the soil is rather poor in sulfur, it can have fertilizing effect. On the other hand, a scientific study has established an increased concentration of sulfur in the vicinity (< 700 m) of RE’s power plants. The effects of this concentration on vegetation, i.e. moss, have not been established. Damages in moss proved very similar to weathering effects observed in the study’s control area, 10 km away from the plant. Similar weather damages were found further away from the plant than 700 m, where increased levels of sulfur were not detected. The reporter’s statement on this issue is exaggerated and not in compliance with the aforementioned findings.”

In an article on “Promoting Geothermal Energy: Air Emissions compared” published in The Electricity Journal of August-September 2005,  Karl Gawell and Alyssa Kagel of the U.S. Geothermal Energy Association (GEA) compare emissions of different energy types.

CO2 emissions for a geothermal power plant (flash) are 60 lbs/ MWh produced, compared to oil with 1,672 lbs/ MWh and coal with 2,191 lbs/ MWh.

This report shows clearly the advantages of base-load geothermal power compared to other energy forms. Furthermore, and this is totally neglected by the article referred to, is that binary geothermal technolgy simply has no emissions at all, as it is a closed circle system. So to generalize “geothermal” like this is also not very professional.

Sources: “Promoting Geothermal Energy: Air Emissions Comparison and Externality Analysis” (K. Gawell/ A. Kagel, The Electricity Journal, Volume 18, Issue 7, August-September 2005), Press Release by Reykjavik Energy (pdf May 28, 2009) , The referenced Article “Geothermal not so clean” (Lowana Veal, IPS News)