Innovative CO2 capture technology at geothermal plant could be applied elsewhere

Innovative CO2 capture technology at geothermal plant could be applied elsewhere Core from CarbFix site (source: CarbFix project, Orkuveita Reykjavikur)
Alexander Richter 22 Nov 2018

The CarbFix project at the geothermal power plant of Hellisheidi in Iceland successfully manages to bind CO2 into rocks and could provide a solution for other industries in Iceland and beyond.

The innovative CarbFix project at the Hellisheidi geothermal power plant of Reykjavik Energy/ ON in Iceland has made the news several times over the past few years, but increasingly in recent times due to its success and possible implications going forward.

“This is by it­self a simple met­hod,” says Edda Sif Pind Ara­dótt­ir, Proj­ect Mana­ger at Car­bFix Team at Hell­is­heidi. Over the past twel­ve ye­ars, a process has been developed which has resulted in the cur­rent comm­it­ment of app­rox­ima­tely 10,000 tonn­es of car­bon di­ox­i­de per year to the em­issi­ons of the Hell­is­heidi geothermal power plant and the maj­o­rity of the hydrogen sulfide relea­sed by the plant.

Started twel­ve ye­ars ago, scient­ists have colla­borated with the industrial and technical staff of Orku­veita Reykja­vík­ur (Reykjavik Energy) and its su­bsidi­aries, ON Power and Veitur utilities, develop­ing and test­ing the idea that car­bon di­ox­i­de that comes up with geot­hermal brine, mix it with water and pump it back down to earth from wh­ere it came. Th­ere it is per­man­ently bound in the form of stone.

Placing gas mixt­ure in a shower

Edda says that both car­bon di­ox­i­de (CO2) and hydrogen sulfide (H2S) dis­sol­ve in water. “The gases are cleared from ot­her gas elements within the geot­hermal brine by putt­ing the gas mixt­ure through a shower when it comes from the power plant. We take the liquid with the dis­sol­ved gas and pump it down into rock layers, “says Edda.

This in­volves a natural process that occurs in basalt, which results in the dis­sol­ved gases binding itself in the rocks underneath. “Wit­hin two ye­ars, they have become rock and we do not have to think about them anymore,” Edda says, and explains that in or­der to describe the matter in a very simple way, we simply say that we are turning gas into rock.

“In fact, we are only utiliz­ing the natural processes that are part of the natural cycle of these su­bst­ances. Especially, we have disrupted the car­bon cycle by burning a lot of highly fossil fu­els over the past deca­des, “says Edda.

Using the method elsewhere

A recent article in Iceland even raises the question if the technology used at the Hellisheidi plant could also be used to dispose of the emissions of an aluminium smelter in Ice­land. Edda says it is possi­ble to app­ly their met­hod reg­ar­dless of the type of power generati­on or indus­try.

“Th­ere must be three things; the intention to reduce car­bon di­ox­i­de em­issi­ons, and access to water and basalt in the vic­inity, “says Edda. She po­ints out that almost all Ice­land is made of basalt.

“It is possi­ble to use the met­hod, whet­her it is a smelter or any ot­her plant in Ice­land. There might be a need to change the process somewhat, as we optimized the process based on the conditions at Hellisheidi, wh­ere we clean car­bon di­ox­i­de and hydrogine sulfide combined. Th­ere are min­or imp­lementati­on issu­es that need to be consi­d­ered, but broa­dly speak­ing, other industries can simula­te what we do.”

She says that the team at Hell­is­heidi Power Plant has been able to significantly reduce costs by being resourcef­ul and app­lying a simple met­hod for gas cle­an­ing; which can be what we call “Soda Stream”.