Carbon injection site, Hellisheidi geothermal power plant. Courtesy Martin Stute. CLICK FOR LARGER SIZE
Iceland has a complicated relationship with climate change. As in much of the far north, global warming is already exerting many effects here–arguably both good and bad. Yet the country contributes relatively little to the warming, since most of its energy comes from geothermal and hydro plants, which produce little carbon dioxide. Now, it is on the scientific cutting edge of the issue. With the aid of scientists from Columbia University’s Lamont-Doherty Earth Observatory, the University of Iceland and other institutions, its main geothermal plant is running the CarbFix project, which traps CO2 emissions and pumps them back underground, to be turned into stone. The new technology may help not just Iceland but other countries to cut CO2 emissions.
All photos: Kevin Krajick unless otherwise credited.
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Iceland is basically one very large active volcanic system. The Hellisheidi geothermal power station—the world’s largest–taps energy from hot subterranean rocks, generating heat and hot water for the nearby capital of Reykjavik, and electricity for industry. Pipelines can channel 600 liters per second of volcanically heated water.
Ninety-nine percent of Hellisheidi’s emissions are harmless steam. But it also vents volcanic gases—mainly 40,000 tons of carbon dioxide a year, and powerful whiffs of hydrogen sulfide, which sometimes plague Reykjavik. With government cracking down on emissions, the plant is creating a system to get rid of both gases.
The secret to permanently storing carbon underground is basalt, the volcanic rock that underlies 90 percent of Iceland. Near the southern coast, the landmark Black Falls plunges over a precipice of pure basalt columns. Because of its chemical makeup, the rock naturally reacts with carbon dioxide, eventually turning it to a limestone-like solid. In nature, the process is usually slow; at Hellisheidi, engineers have figured out how to speed it up.
At tourist-friendly Geysir, fountains of volcanically-driven water periodically erupt from hot pools like this one. Around the edges, white carbonate crusts have formed, as minerals precipitate out—a natural analog to the processes harnessed at Hellisheidi. Geysers worldwide get their name from Geysir.
A system designed by chemical engineer Magnus Thor Arnarson (left) separates carbon dioxide and hydrogen sulfide from steam. Reykjavik Energy, which runs the plant, put it into full-time operation in September 2014. The concept was proved up when chemical tracer tests at a nearby pilot site indicated that pressurized carbon injected into basalt below was rapidly solidifying. The new separator removes about 20 percent of the plant’s emissions; planned expansions should eventually remove all.
Gases from the separator are dissolved in water and piped to this injection shed, a half-mile from the power plant.
Inside, the injection pipe plunges 2,000 meters into the ground. CarbFix project manager Edda Sif Aradottir (right) inspects the installation with Lamont-Doherty hydrologist Martin Stute and Arnarson.
The team can check through a window to make sure the highly pressurized gases are completely dissolved before going down. “If these pipes broke, we would all die in a couple of seconds,” notes Aradottir. She earned her PhD. in geochemistry working on the project.
At the earlier experimental injection site, scientists initially measured carbon solidification by analyzing the chemistry of water from a monitoring well. Now, the team is drilling down to bring up actual rock samples to confirm the results and study details.
When the drilling crew hits 400-plus meters, they start bringing up pipes containing cores of basalt into which the CO2 was injected.
In a nearby shed, Lamont adjunct geochemist Juerg Matter (left) and microbiologist Rosalia Trias of the Paris Institute of Earth Physics inspect a freshly retrieved core. Visual inspection and analysis of the rocks’ chemistry and microbiology should help the team better understand and refine the process.
The prize of the day: University of Iceland geologist Sandra Snaebjornsdottir displays a core of porous basalt heavily laced with carbonate minerals—tangible evidence of the process at work.
Parts of the core contain green slime—possibly waste products of underground microbes thriving on the rush of pumped-down carbon. The French team believes that injection may drastically alter the little-known ecology of the deep underground, and that biota might play a role in the solidification process. They plan to study DNA in the samples.
Plants like Hellisheidi (seen here from the drill site) could grow and multiply if proponents win on a proposal to lay a giant undersea electric-transmission cable to Europe. This would allow Iceland to export huge stores untapped energy; but many worry it would mar the landscape, and introduce new environmental challenges.
As in much of the north, warming climate is already visibly affecting Iceland, where average temperatures are going up faster than in most of the rest of the world. Some effects are arguably good; for one, farmers who have struggled for centuries against chilly weather are seeing better plant growth. This farm abuts Myrdalsjokull ice cap, on the southeast coast.
Other possible upsides to global warming: commercial fish stocks that used to stay farther south are moving up. And, foreign investors are showing interest in real estate on the island’s rocky shores, which offer a gateway to the Arctic Ocean.
Iceland’s glaciers cover more than 10 percent of the country, but now they are disintegrating. At the Jokulsarlon glacial lagoon, icebergs calve off and float around before washing out to the nearby Atlantic Ocean. The lagoon has grown fourfold since the 1970s and now covers close to seven square miles, as the ice pulls back.
The rapidly wasting surface of the Skaftafellsjokull glacier concentrates a monochrome of rocky debris; the dark coating absorbs solar radiation, which in turn encourages more melting.
Volunteers from the Iceland Glaciological Society have spent decades measuring the decline and fall of the once-mighty Solheimajokull glacier. A sign planted where ice stood just a few years ago records the most recent declines. If trends hold up, by 2100 Iceland may be mostly land and very little ice.
The melting of ice could increase seasonal floods or, as some scientists fear, reduce pressure on volcanoes currently buried under glaciers, and help uncork eruptions. Throughout Iceland’s history, under-ice eruptions have unleashed epic floods; one in 1362 created the vast, lifeless outwash plain of volcanic rocks below this farm, stretching some 50 kilometers. The district has been called Oraefi, or Wasteland, ever since.
A more recent flood created this bridge to nowhere. Flood waters obliterated the road, and relocated the river the bridge once crossed several hundred meters away.
Increased water flow has a temporary upside: increased hydropower potential. The iconic Golden Falls, outside Reykjavik, will probably never be dammed, but other sites well may be—at least until glacial runoff peters out. (Courtesy Martin Stute, Lamont-Doherty Earth Observatory)
Over a plain of moss-covered basalt boulders, Lamont hydrologist Martin Stute passes a water-supply line near the Hellisheidi power plant. it is easy to think of Iceland’s landscapes as set apart from the outside world—but they are intimately bound to it.