all stabilization scenarios indicate that a huge share of emissions reductions in the range of per cent would come from changes in energy systems it has been found that this will require different sets of mitigation options across regions with varying shares of renewable energy nuclear energy carbon capture and sequestration ccs biomass and hydrogen and other advanced energy carriers in a way it is a prerequisite for increasing shares of zerocarbon energy systems however it would be wrong to overestimate its contribution even in advanced economies barker dagoumas and rubin