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Investment in renewables worldwide equals that for fossil fuels electricity for the first time, and continues to grow. Even if fossil fuel extraction and exploitation continues for many decades, it is increasingly conditional on ever greater protection of the environment and atmosphere.


Renewable energy, and sustainable use of fossil fuels will change the emphasis from subsurface extraction towards energy storage and greenhouse gas waste disposal. Given this, decisions on the actions to 2030 need to be taken now. The divergence of the green agenda of Scotland and the pragmatic agenda of the rest of the UK are already


apparent. Indeed, for Scotland, this means moving onwards from low carbon electricity, to the greater energy problem of heat and transport.


Electrification of heat and transport will mean adding 200% extra electricity generation as well as storage to today’s community and national grid systems. Can existing wind generation and new offshore sites deliver this?


If not, hydrogen generation could supply heating through existing gas pipe networks and also be used in fuel cells to power electric vehicles. Meanwhile geothermal heat sourced from aquifers is a further option, (see


‘Electrification of heat and transport’). The choices have yet to be made, but clearly the future of subsurface exploitation is going to change. We will see a gradual transition from the extraction of hydrocarbons, to the extraction of heat, storage of compressed air and hydrogen, as well as the injection of carbon, cold water, and maybe frack fluids.


Perhaps today’s developments signal the end of coal and the decline of North Sea oil, but the start of a new subsurface beginning?


Stuart Haszeldine is Professor of carbon capture and storage, University of Edinburgh.


Electrification of heat and transport


Electrifying the energy system and powering it by low carbon electricity is crucial to decarbonisation but heating and transport services are the two key fossil fuel consumers in the UK. Renewable generation is an alternative, but other options exist. Hydrogen generation, for one, could supply heating through the existing gas pipe network, and could be utilized through fuel cells to power vehicles. But the source of hydrogen creates a political dilemma.


Gasification of coal or steam reforming of methane provide lowest hydrogen through established processes at commercial scale. However, these methods demand large scale use of fossil fuels, and


as a result will provide sustainable, rather than renewable, heat. A carbon dioxide removal infrastructure would also be required, centralised around industrial clusters, linking to storage offshore. Alternatively hydrogen can be generated by electrolysis from renewable electricity, and this has worked on island projects in Shetland and Orkney. However the fuel cost is up to three times that of fossil fuel set-ups.


How much are we prepared to pay? And how much extra cost can the economy withstand whilst remaining competitive? In addition geothermal heat from mid-depth aquifers is under consideration in the UK. Clearly large capacities are available within the UK’s former coal mining areas.


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