CCS Costs CCS Strategy £85/MWh climate change CCS Clusters CCUS Cost Challenge Taskforce CO2MultiStore Cost Reduction COP21 SCCS North Sea fifth carbon budget CCS Technology Cost Challenge Taskforce Energy Bill 2015 Industrial CCS hydrogen CCS competition Spending Review 2015 Oil and Gas Authority CCUS cost-competitive CCS energy demand UNFCCC Phase 2 carbon low-carbon heat regional growth Clean Growth Strategy energy intensive industries CCS Lessons Learned Paris Agreement industrial strategy CO2-EOR Joint Industry Project CCS CCSA infrastructure oil and gas Delivering CCS