are planning huge plants in north—east scotland and texas, which will each remove up to a million tons of carbon dioxide a year. but what of the carbon once it's captured? nick kwek is in iceland, where a very green energy facility is leading the way. this is one of the cleanest geothermal power plants on the planet. but it's also the test bed for some new technology which could make a huge difference when it comes to the global fight against climate change. the hellisheidi power station's emissions are being used by carbon capture and storage company carbfix, that's turning c02 to stone. it comes in directly from the power station and it enters that tower from the bottom here. then we inject cold water at the top and the c02 becomes dissolved in water. crucial to the process is this giant oversized sodastream—like tower. it makes sparkling water, then it's ready to be transported to our injection site.