The science behind the European island’s geothermal resources
March 15th 2015 | Montana | Christopher Beddow
Photograph by Askja Energy
Iceland’s Eyjafjallajökull volcano violently erupted in April of 2010, making international headlines as it grounded international flights on both sides of the Atlantic for several weeks to come.
The tephra produced by the eruption interfered with flight traffic into late spring, but soon settled as the summer tourist season approached. Volcanic activity is commonplace in Iceland, including frequent tectonic changes, occasional smaller eruptions, and a plethora of hot springs and geysers. The tephra produced by past eruptions is usually swept northward by winds, but 2010 proved to be an exception. In centuries past, other Icelandic eruptions have certainly had worldwide effects, particularly in the late 1700s when the atmospheric effects of the eruption of Laki resulted in what the famous Benjamin Franklin, in contemporary writings, described as “the year without a summer”.
Since the 2010 eruption, however, Iceland has seen consistent tourism and expansion of nonstop flights from both Europe and North America. While tourist campaigns particularly emphasize the alluring beauty of Iceland’s volcanoes, the tumultuous landscape offers its patrons much more than just a claim to fame.
The geothermal island
Iceland has been relying on geothermal energy to provide for its needs for decades, and today it is a rare case of a society that is more dependent on renewable resources than it is of traditional fossil fuels such as oil and coal. While automobiles and airplanes see a continued demand for petroleum in Iceland, virtually all other sectors of industry and have seen a shift toward renewable energy. While a handful of power plants provide power to the national grid, many renewable energy sites, particularly geothermal ones, operate at the local scale and provide power for farms and households within a certain radius.
Iceland is situated in a very unique location with regards to geothermal activity. It happens to be a volcanic hotspot which also sits atop the active tectonic rift of the Mid-Atlantic Ridge. The result of this is what we see today; a terrain where volcanic eruptions occur twice or more every decade and where minor volcanic activity is a daily occurrence.
Geothermal energy has proven to be an especially abundant resource as a result of these characteristics, giving Iceland a unique advantage compared to other regions of the world as far as renewable energy generation is concerned. Whilst many countries have a strong focus on solar, wind, and hydroelectric power generation, Iceland is currently able to provide for over 60% of its energy needs using geothermal energy.
Other parts of the world have a similar potential for geothermal development, including the Hawaiian Islands and the area surrounding Mount Fuji in Japan.
Yet, none have been able to harness the natural sources of heat and energy in the way that Iceland has. The European island nation currently has 6 geothermal power plants, and many smaller sites that help convert heat from the ground into usable electricity for the national grid. Of these plants, 5 are located on the Reykjanes Peninsula surrounding the capital city of Reyjavik, 2 of them at Svartsengi, and the other 3 near the towns of Reykjanes, Hellisheidi, and Nesjavellir. Most of Iceland’s population of over 300,000 resides in this area, with volcanic activity including some of Iceland’s most famous geysers in the Haukadalur Valley as well as the world renowned hot spring resort called the Blue Lagoon.
Diagram by Christopher Beddow
Iceland’s geothermal energy is tapped by drilling beneath the surface. Often, this does not have to be very deep, as ground temperature rises rapidly near areas with tectonic activity. Groundwater running through these hot earth zones turns to steam, which can sometimes be seen emanating from geysers and hot springs. Many of these geothermal reservoirs have no actual other way of flowing out into open air. Apart from drilling, another method is to provide water externally and let it be heated by geothermal sources in order to produce steam. In both cases, steam is used to power turbines, thus generating an output of energy.
A global outlook?
Geothermal power plants produce a byproduct called brine, a type of contaminated water which must be carefully cooled down and separated in order to prevent it from mixing with freshwater ecosystems. In many places around the world, brine is not handled with care and can present a serious threat to fish, plants, and other parts of the environment. Overall, geothermal plants have a very low rate of carbon emission, often near-zero, but responsible maintenance and handling of byproducts is an essential requirement for it to be considered a truly clean source of energy.
When it comes to percent of clean energy meeting society’s needs, Iceland is a world leader. While its circumstances certainly cannot be replicated at will in other countries, teams from Iceland have been actively working around the globe to help develop other geothermal energy projects insofar as geological conditions permit. There are active volcanic regions on every continent of the Earth, and although they have often been regarded as dangers in the past, many of them hold future potential as abundant energy reserves. North America, Europe, Asia, and Africa have all began developing geothermal energy systems, and in some cases Icelandic participation has contributed to their success substantially.
Diagram by Icelandic National Energy Authority
Although geothermal energy can provide an essentially endless supply of power, there are also potential dangers associated with over-development. The geothermal process is in some ways similar to fracking, or hydraulic fracturing – which involves drilling into the earth and injecting fluids into shale rock layers in order to fracture the earth and release natural gas deposits. While fracking releases natural gases such as methane and other hydrocarbons, geothermal drilling only releases water vapor. Yet, in both cases, water is injected directly into the rock with the specific intention of causing fractures, which can cause small earthquakes to occur. However, these are often at a magnitude of around 1, which is unlikely to pose any real threat to infrastructure.
21st century prospects
Future geothermal projects in Iceland include the Iceland Deep Drilling Project (IDDP), which plans to test the practice of boring over 5 kilometers into the earth in order to extract heat from some of Iceland’s largest geothermal reservoirs.
This depth, double that of conventional plants, is ambitious, but perhaps also dangerous. A feasibility report by the IDDP acknowledged the possibility of damage to geological features and formations, to wetlands and sensitive areas, and to local flora and fauna. However, these risks were deemed to be easily mitigated by undertaking the drilling far from roads. This would ensure that any damage is neither noticeable nor of any real social importance. The opposition to this project appears to be relatively silent, there has been very little activism on the issue, which suggests that there are no major concerns about the long-term risk of geothermal drilling to local communities. If all of this is correct, then the IDDP may represent a revolutionary step forward in renewable energy, allowing for much larger-scale extraction of geothermal resources that may further reduce the need for fossil fuels in grid distributed energy.
Photograph by Christopher Beddow
Iceland, while not without its troubles, has recently become one of the world’s wealthiest, most stable, and most energy independent nations, despite being isolated and economically poor only a century ago. This very same isolation has contributed to the need for local energy development, in what is referred to as a spatially segregated system rather than one which is well-integrated with neighboring countries.
As an island, Iceland has found that it is burdened with a more crucial need for self-sufficiency, and geothermal power has played a large part in achieving this. As the European nation continues to improve its own energy ecosystem, it has the noble goal of lending both knowledge and helping hands to other nations in their own endeavor for energy independence.
Geothermal energy as a whole is one of the many beacons of hope in our world’s future, and with sufficient effort and funding it has the potential to make other regions of the world as commendable and remarkable as the beautiful, volcano-covered country of Iceland.