In Reykjavik the first house to be heated with geothermal water was the newly built Austurbæjarskóli, in 1930. The water was pumped from the Laugardalur area. Laugardalur is actually in my neighbourhood, this is where the big outdoor Laugardalslaug is today and were women would bring clothes and linnen to wash in natural hot water in outdoor communal washbasins.
Washbasin in Laugardalur, early 20th century. You can still see the remains of the basins today.
The technology spread and a few decades later the city was heated almost exclusively geothermally. The growing city and increased demand meant that water had to be pumped from further afar and from more depth. With more sophisticated technology and investment, superhot water can be reached hundreds or even thousands of meters below the surface, which can be harnessed for making electricity with steam turbines. The geothermal plant in Svartsengi was started in 1976 and today four such plants are operated in the country, producing 800 MW of electrical power.
Svartsengi geothermal power plant
This sounds really great, we don't have to burn fossil fuels but can simply pump up hot water, convert the heat to power, and pump the water back down again.
But reality is not quite black and white. Geothermal is - not quite yet - the ultimate totally renewable 100% clean energy source that we would like it to be.
First, one must realise that 'low temperature' water use, such as pumping 80-100°C water from 50-100 m depth and circulating for heating houses, is something quite different from 'high temperature' water use, where superhot water (250-300°C) is pumped from maybe >2000 m depth.
When you pump up superhot water, you get other stuff up as well. Quite a bit of CO2 is dissolved in the hot steam. The CO2 emission are much less per unit produced energy then in a coal or gas fired power plant, but still they are not negligible. According to a report from the Iceland Energy Authority, geothermal electricity production releases about 12% of the CO2 that a conventional fossil fuel burning plant would emit. In fact, an Iceland based company has just built a pilot scale plant to use some of the CO2 and convert it to methanol fuel.
Other pollutants are of more immediate and local concern. The 300 MW Hellisheidi plant located about 25 km from the eastern suburbs of Reykjavik releases so much SO2 (sulphur dioxide) that the air quality of the city substantially decreased after the plant was started in 2006. Three times in 2011 the sulphur in the atmosphere was above maximum permitted levels according to health regulations. Morgunbladid reported this spring that Icelandic sound studios now notice that their expensive high quality mixers (that have real silver leads) don't last nearly as long as they should. "A few years ago you would set up new equipment and you didn't have to think about it until some years later when you would clean it, replace worn out switches and such. Now, the whole thing starts to crackling and hissing in a year or two" says sound technician Jakob Tryggvason.
It took me some time to find actual numbers for the sulphur emissions, but I finally found a response that the minister of environment gave to Parliament two years ago. 60.000 tonnes is the estimated amount of emitted sulphur compounds from the geothermal plants, calculated in SO2 equivalents. That is 4x more than all other emitted sulphur in Iceland, from all other sources combined ("man made"), including aluminium smelters, all other industry, trucks, ships, etc.
The sulphur emissions vary between the different geothermal plants, there is much less from the Svartsengi plant (by Blue Lagoon) than from Hellisheidi. (This is thought to be because the hot water below Hellisheidi is closer to a magma chamber.) Hellisheidi is also the largest geotherma plant in Iceland, producing about 38% of the total geothermal energy. This means that a substantial part of the 60 ktonnes of sulphur emitted into the air comes from this one source close to Reykjavik. (I have read that the staff at the plant don't want to drive their own cars to work and park them all day because of the corroding air and silica precipitates from venting steam.)
Steam vent at Hellisheidi. (I ruined the filter on my camera lens when shooting this picture.)
If I have understood this report correctly, all the 27 EU states combined emit about 8.000 kilotonnes. 60 ktonnes might sound like a lot less than 8.000, to be exact it is 0.75% - three quarters of one percent. But keep in mind that the population of Iceland is 0,320 million compared to EU's 502 million citizens - Icelanders are 0,06% the size of the EU population. This means that sulphur emissions from Iceland's geothermal power plants per capita are 12.5 times more than the total per capita sulphur emissions in EU!
Clean energy? I don't think so.
Apart from these serious environmental concerns, other challenges come with geothermal plants. Some of these the citizens of Reykjavik have come to learn the hard way. It is difficult to predict in advance how much energy can be harnessed from a particular geothermal area. Therefore it is generally recommended to build up utilisation incrementally, start with a relatively small plant and see how the system behaves, and then stepwise add to the plant. In Hellisheidi, the directors of the Reykjavik municipal energy services had no patience for that, this was in the heydays leading up to the crash; everything should be big and fast, and the energy providers needed a big plant to provide energy to an expansion of the Grundartangi aluminum plant.
The consequences, besides the surprisingly high sulphur pollution (and foreign currency financing of the plant that badly hurts the budget of Reykjavik and have caused higher heating costs for Reykjavik households), is that the 300 MW plant seems to be draining too much energy from the Hellisheidi area, today it is only producing 276 MW of energy and the capacity goes down by about 2.3% per year.
Hellisheidi power plant
Apart from, this, the operators at Hellisheidi are having some difficulties getting rid of the quite enormous amount of water that is pumped up, which contains a lot of dissolved chemicals - minerals, salts, silica compounds, heavy metals and other non pleasant stuff that must not get into the ground water. After the heat is extracted from the water it must somehow be disposed safely. The run-off water has been pumped back down using designated boreholes but reports tell that the receiving capacity of the return boreholes is diminishing. (Each borehole costs millions of Euros to drill.)
So when you hear the president give one of his talks about the wonderful sustainable renewable and clean energy of Iceland (such as this one where he mentions clean energy 22 times), take it with a grain of salt. He gives a rosy view of a more complex and challenging issue.
For more, see also:
Saving Iceland - Hellisheidi: a geothermal embarrassment
The Iceland Weather Report - Yet another train wreck on the environmental front
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