How many technologies do we have that can vanish gigatonnes of CO2 each year? CCS stands alone

year, which amounts to 60 billion cubic metres of compressed CO2 under the typical conditions in Earth’s crust, he says. “That’s more than 10 times the volume of oil that is transported around the globe on a daily basis. Of course we don’t expect that one single technology will take our
emissions to zero, but this gives a sense of the scale of the problem.” Juanes and other experts say CCS is only a bridge technology. It could buy time to make the switch from fossil fuels to renewables. The question is, “how long is that bridge”, and will it be enough? He studied 11 US saline aquifers, geological formations that could store CO2, and calculated that they could hold 100 years’ worth of US emissions (PNAS, doi.org/rqs). The North Sea is said to have room for 100 years of European emissions. The big hurdle for CCS is money. Adding chemical scrubbers to a power station uses about 20 per cent of its power output. Power companies are unlikely to pay that hefty cost without incentives. For now the cost of electricity from a CCS power plant is higher than normal fossil fuels but close to wind energy, says Haszeldine. The most pricey bit is reheating the solvent to release captured CO2. Researchers are now looking into scrubbing reactions that use less energy. If that works, power plants could use residual heat alone to drive the reaction. That is still in the R&D phase, with tangible results 10 to 15 years away. But Haszeldine says a similar technology – scrubbing sulphur dioxide pollution from power station emissions – was once dismissed as impossibly expensive, but now runs on most power stations for little extra cost. We need to do more than CCS  to save ourselves from climate change. But, asks Juanes, how many technologies can vanish gigatonnes of CO2each year?  “The answer is none,” he says.  “I think CCS stands alone.”