Deep geothermal ambitions in Norway
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Energy Quarterly
Deep geothermal ambitions in Norway By Arthur L. Robinson Feature Editor Volker Oye
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orway is blessed with abundant cheap hydroelectric power, limited only by occasional drought years and vast reserves of off-shore oil and gas that are sold on the European market in Rotterdam for national income rather than for domestic use. So the question arises: Why deep geothermal energy in Norway? Geothermal energy derives from the heat in the interior of the Earth that slowly makes its way by convection and conduction toward the surface, where it is radiated into space. Drilling into the Earth to capture the heat can provide the power for applications from building heating to electricity generation. Currently, the bestdeveloped sources are hydrothermal fields near hot spots where magma penetrates into the Earth’s crust, as it does in Iceland. But the potential for geothermal energy is theoretically enormous. The International Energy Agency (IEA) estimates that the heat flowing into the top few kilometers of the Earth’s crust is more than two million times the world’s annual total energy consumption There are two ways to tap this heat. Shallow (less than 500 m) geothermal energy is relatively well developed in
more than 80 countries, but the comparatively low temperatures (below 50°C) away from hot spots mostly limit the applications to smaller scale heating, often based on heat pumps. Nonetheless, Kirsti Midttømme of Christian Michelsen Research AS in Bergen said, “shallow geothermal is and will be a major contributor to the Norwegian energy supply for at least the next 50 years.” Away from hydrothermal fields, to reach the higher temperatures suitable for large-area (district) heating and electrical-power generation requires drilling 3–5 km or more below the Earth’s surface. This deep geothermal energy is renewable indefinitely, suitable for baseload electricity, and can be sited almost anywhere. But the deeper the bore hole the more hostile the high-temperature, high-pressure, corrosive environment. Moreover, Norway’s geology is dominated by crystalline rock that is hard to drill through and generally has low permeability for hot fluid flow. These features pose as-yet unsolved technological challenges and high costs, so there are no deep geothermal plants in Norway. “The high cost of drilling longreach wells in hard rock formations is the showstopper for the widespread exploitation of deep geothermal energy,” said Are Lund and Odd-Geir Lademo of SINTEF Materials and Chemistry. Global climate change might provide an entrée. Norway has been ramping up a nationwide effort marked by joint government and industry investment to develop a comprehensive portfolio of clean and renewable energy sources with the goal of becoming carbon neutral by 2050 or sooner. To help raise geothermal’s profile among energy alternatives, a consortium of industrial, academic, and research institutions established in 2009 the Norwegian Center for Geothermal Energy Research (CGER) in Bergen, hosted by Christian Michelsen Research. H
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