By eevenden
Gleðilegan laugardag! (Happy Saturday!)
Many people think of Iceland as a haven for environmentalism. Known for its geothermal power, the country has become a leader in sustainable energy. The commitment to sustainability here, in many respects, is greater than what I have experienced in the U.S. (though I suppose that bar is pretty low). In this week’s blog post, I’ll discuss Iceland’s geothermal energy production. In a week or two, I’ll write a follow up post about other facets of sustainability in Iceland. Much of the information below comes from the lectures in my Sustainable Energy course, as well as the links at the very end of the post.
How does geothermal energy work?
Before delving into geothermal energy in Iceland, let me first summarize what geothermal energy is and how it is harnessed. Geothermal energy, or heat released by the Earth, is a product of radioactive decay in the Earth’s core. As atoms within the Earth become more stable, they release energy in the form of heat. This heat travels to the Earth’s surface where we experience it in several forms, including volcanoes: steam vents, geothermal springs, etc.
In Iceland specifically, there are over 200 volcanoes, 34 high-temperature areas (steam fields where the ground temperature is greater than 150 degrees Celsius), and 250 low- temperature areas (where the ground temperature is less than 150 degrees Celsius).
Geothermal energy can be used in two primary ways: directly to heat water, and indirectly to create electricity. Typically in geothermal plants, bore holes are drilled several kilometers deep into the ground in order to access high-temperature zones deep in the Earth’s crust. To capture this energy, water is pumped into the bore holes and absorbs the heat, bringing it back up to the surface.
In order to make electricity from geothermal energy, one needs a high-temperature geothermal zone (where the Earth’s deeper temperature is around 1000 degrees Celsius). When water is pumped into an extremely hot bore hole, it turns into extremely hot steam which is then used to spin a turbine at the surface to create electricity.
Meanwhile, cooler geothermal areas are used to heat water, which is then distributed through pipes to towns in order to heat buildings. Geothermal energy is used to heat homes using heat pumps, an underground mechanisms with collects heat from an water tank (or the ground in some places) and carries into the house. Here is a video about heat pumps if it sounds a bit confusing.
History of Energy Resources in Iceland
Prior to fossil fuels, Iceland primarily relied on peat, seaweed, and animal dung as its sources of energy. Unlike in the U.S. and much of Europe, Iceland had very few forests because all of its trees were cut down by its settlers in the Medieval Ages. Regrowth rates are not very fast on this icy rock. As a result, wood was not a plentiful source of light and heat like in Iceland’s Scandinavian counterparts. Fossil fuels slowly came to Iceland starting in 1870 with coal. Between 1950 and 1960, oil replaced coal as the predominant source of energy.
Meanwhile, geothermal energy has also been exploited over the last 1000 years in Iceland, and was originally used for washing, bathing, and cooking. Geothermal energy was first used to heat homes in 1908. Back then, two homes used pipes to carry heated geothermal water to them. Starting in the 1920s, people started drilling in geothermal areas on a larger scale. These sites were almost completely low-temperature areas, which meant that they were fine for heating homes, but could not generate electricity. By 1940, 2,700 homes were heated by geothermal energy. Today, 90% of Icelandic homes are heated with geothermal energy.
It was the Arab Oil Crisis which forced Iceland to commit to using geothermal energy. When the crisis stuck, imported oil provided heating for 50% of homes in Iceland, and electricity for the entire country. Prices for oil skyrocketed, causing the Icelandic government to remove subsidies for oil, and instead emphasize domestic energy resources including geothermal and hydropower. Today, approximately 60% of Iceland’s primary energy comes from geothermal, and 15% comes from hydropower. The remaining 25% is primarily from oil, and a small fraction of coal. It should be noted that these resources are used for different things. Most geothermal energy is used to heat buildings, while only providing 25% of Iceland’s electricity. 70% of electricity is produced by hydropower, and fossil fuels are mostly used for transportation.
Energy Consumption in Iceland
Though much of Iceland’s energy (heat, electricity, and transportation) is produced from more sustainable methods (primarily geothermal and hydropower), it still has one of the highest rates of energy consumption per capita, nearly equivalent to American and Canadian rates. Why is this? Obviously, using renewable energy sources does not mean people will consume less energy. In fact, some argue that it is an invitation to use more energy. I have definitely seen this to some extent in Iceland. For example, in my experience, houses here are not designed to be very thermally-efficient. Often I have heard exchange student complaining that their homes being very drafty (including mine). And most buildings here have large, single-pane windows which aren’t very good at trapping heat. Additionally, since few houses here have central heating or cooling, people leave their windows and doors open all the time in order to bring fresh air into the house. And when you’re trying to air-out your house in the Icelandic winter… “just turn up the heat a bit more”. However, this problem of inefficient homes is not exclusively Icelandic. We see it everywhere, including the U.S. - problems with building design and architecture, and the quality of these structures. And despite this example, Icelandic households are not the largest energy consumer by far in the country.
Households and utilities in Iceland only consume about 10% of the country’s total energy. Instead, the vast majority of energy consumption comes from industry. 74% of Iceland’s energy is consumed by three aluminum smelting plants, as of 2014. The aluminum-smelting industry is very controversial in Iceland, as I mentioned in my blog about Icelandic history. Not only do these plants increase the country’s energy consumption enormously, but they also are a large source of pollution in Iceland, emitting high amounts of sulfur, fluoride, and heavy metals. The other primary consumers of Icelandic energy include its silicon-smelting industry (which has also received a lot of public backlash due to air pollution), as well as agriculture, and other smaller industries.
Benefits and Consequences of Geothermal
Though from the outside geothermal power seems very sustainable, this is not the opinion of some Icelanders. In fact, there has been a lot of discussion here recently about moving away from geothermal and hydropower for electricity-generation, and instead focusing on tidal power which may have less environmental impact. Here is a short summary of some advantages and disadvantages of geothermal energy (based on what we have learned in class).
Advantages
- Geothermal energy is a reliable and perpetual energy source.
- The operational cost of a geothermal power plant is relatively low.
- There are few greenhouse gas emissions.
- The heat transfer process is relatively efficient.
Disadvantages
- Bore holes do not have an unlimited lifetime since their temperature gradually falls as more heat is extracted. Often new boreholes have to be drilled every few years.
- There is potential for water pollution since water pumped into boreholes contains dissolved chemicals from rocks including sulfur, carbon dioxide, ammonia, arsenic, boron, and mercury.
- Thermal pollution is another potential problem if power plants release steam, or if old bore holes are left open to vent
- There is a very high start-up cost for geothermal plants. Additionally, the process of siting a geothermal plant is very long since it requires a lot of temperature monitoring and analysis.
- Land subsidence can happen as a result of geothermal extraction.
Hopefully this blog provided some insight into geothermal power production and Iceland's sustainability. This week is my spring break, so I will be travelling to the U.K. on Tuesday. More information about that to come!
-Emily
Additional sources
Article about aluminum smelting - http://icelandreview.com/news/2013/10/18/pollution-southwest-iceland-industrial-area
Icelandic source for the aluminum smelting article - http://www.ruv.is/frett/geysileg-mengun-i-hafnarfirdi
FAQ about aluminum smelting in Iceland - http://icelandreview.com/stuff/ask-ir/2014/12/26/aluminum-smelters-iceland
Silicon pollution in Iceland - http://icelandreview.com/news/2016/11/28/pollution-complaints-about-silicon-smelter
Saving Iceland webpage - http://www.savingiceland.org/