The tiny nation of Iceland is often cited as a model for the world in its use of renewable energy. Virtually all of its electricity comes from dams or geothermal power plants. Drive around the countryside, as I did last month, and you will see billows of steam coming from some hillsides, a sure sign of a geothermal operation with the occasional hot springs attached.
Some Icelanders are questioning just how long the renewable power can last. At the core of the debate are the country’s efforts to build up a power-intensive aluminum industry — itself an effort to diversify the economy away from fishing. Already some 80 percent of Iceland’s electricity goes to heavy industry, mainly the country’s three big aluminum plants, according to Iceland’s new environment minister, Svandís Svavarsdóttir.
Work has begun on a new aluminum plant near the airport, though it appears to be proceeding only slowly. Arni Finnsson, the head of Iceland’s Nature Conservation Association, argues that the plant would be such an energy hog that it would “virtually wipe out all geothermal electricity in southwest Iceland.”
Environmentalists appear to have a strong ally in the government: Ms. Svavarsdóttir said in an e-mail message that she and her party were “very skeptical about the further expansion of the aluminum industry, to say the least.” She also vowed to “press for a more rational and balanced decision-making in this regard.” (See her full responses to my questions here.)
Why is there a limit to geothermal energy? According to Mr. Finnsson, if Iceland’s resources are tapped too quickly, the underground hot water necessary to produce the power (and heat buildings in Iceland) could run out in 70 years or so. Geothermal energy, he said, is “not renewable if you use it to an extreme.”
Ms. Svavarsdóttir agreed that overuse of the resource could lead to a “temporary depletion of a geothermal field,” and also noted the hydrogen sulfide pollution concerns related to geothermal production.
A similar debate has been ongoing in Iceland over the use of dams to power aluminum plants.
Environmental groups are worried that more dams could be built, and Mr. Finnsson also argues that hydropower, like geothermal power, is not necessarily renewable. The dams have a finite lifespan, he said, because the glacial silt that washes down the rivers gets stuck in the reservoirs, causing them to fill up over time.