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