German scientists created process to turn carbon dioxide from air into liquid hydrogen . Theory has been around since 1970s , but implementation too costly until now . So , why waste hard-won green electricity to produce old-fashioned petrol ? Process requires ultra - high temperatures , industrial production a long way off . It could also be used to store electricity , from wind , solar power .
German scientists created process to turn carbon dioxide from air into liquid hydrogen . Theory has been around since 1970s , but implementation too costly until now . Process requires ultra - high temperatures , industrial production a long way off . It could also be used to store electricity , from wind , solar power .