Four kilometres down, temperatures and pressures create opportunities!
Far out on the southwestern tip of Iceland’s Reykjanes Peninsula, a partnership between the government of Iceland and a number of large companies is closing in on a goal they set initially for themselves almost two decades ago: to produce electricity from supercritical volcanic fluids that sit – under extremely high pressure – next to active magma chambers over four-and-a half kilometres below the earth’s surface.
The concept is to drill down and tap into these supercritical fluids (supercritical being defined as substances subjected to temperatures and pressures above a point at which neither liquid or gas phases exist), and bring back that heat in the form of super heated steam (at 400-600 degrees C) to create geothermal electricity. The resulting wells – if they can get to the commercial stage – are expected to be up to ten times as productive as existing geothermal wells, at a potentially much lower cost.
Iceland seeks to extend its considerable geothermal expertise
Iceland already has more electricity per capita than any other country (more than twice that of the nearest contender, Norway), but the country is always searching for the next energy opportunity, and a way to further develop its renewable energy resources. To that end, a consortium of three Icelandic energy companies embarked on a quest – beginning in the year 2000 – to access the enormous energy potential of a geological plate formation on a mid-ocean ridge that lies beneath the country.
Iceland is no stranger to geothermal energy – it currently gets over a quarter of its electricity (about 665 MW) from geothermal wells. But what distinguishes this deep drilling effort from conventional geothermal projects is both its ultimate depth and potential reward. The exploratory wells are twice as deep as traditional wells, and the output may be ten times as great. Since the earliest days of the project, other companies have since joined. International aluminium giant Alcoa and Norwegian oil company Statoil are now also partners in the endeavour.
Early failures and eventual success
The deep drilling project has already seen two previous failures: a 2005 well that reached three kilometres was blocked during a production test, and a 2009 well that drilled into molten rock at just over two kilometres down, with 900 degree magma eventually plugging the hole. The operators were nonetheless able to access and test steam flows equal to about 35 megawatts of power output, making it the most powerful geothermal well on the planet at that time. It was eventually shut down after a valve failed during an attempt to connect the project to the power grid.
Nonetheless, the consortium kept pushing, with the latest well having been successfully completed in January 2017, at 4,659 meters after 176 days of drilling. The principal physical objectives of extracting drilling cores, measuring temperatures (427 degrees C), and establishing permeability of the rocks (so that water can be injected to be turned into steam) have been achieved.
Establishing the commercial potential
Although the drilling has now been completed, it will be more than three years before the project reaches conclusion. During this period, more research, testing, and flow simulations will be performed to help determine the overall economics and commercial viability. The supercritical fluids environment is a new one for geothermal production, so there is still much to find out.
If the science and economics bear out, the deep drilling project could open up whole new areas for geothermal production, both in Iceland and elsewhere. Fewer geothermal wells would ultimately be required, with better economics and reduced environmental impact.
Implications for the planet and for Iceland’s energy economy
If the project proves both successful and commercially viable, the project has significant implications both for the planet and for Iceland’s energy economy.
Iceland’s pioneering work in the developing potentially cost-effectively deep geothermal resource holds out enormous promise for countries across the planet, wherever suitable geology exists, especially regions that sit astride tectonic plates. So many countries are watching the results of this project.
At the same time, these new geothermal resources may help further stimulate Iceland’s burgeoning green energy economy. Unlike intermittent renewables such as wind and solar power, geothermal energy provides a reliable source of dispatch-able base-load power (it can be ramped up or down as needed to better meet overall demand).
Increased geothermal will allow Iceland to further build out its clean power grid with reliable and inexpensive energy resources. This will in turn attract more energy-intensive industries - ranging from aluminium smelters to high performance data centers - looking for inexpensive and environmentally benign energy resources with significant potential for further expansion.