Wind, solar and storage now look like the cheapest power mix for the UK, with a new report from the Royal Society looking to ‘200 GW of wind & solar capacity & 100 TWh of storage capacity’, by 2050, assuming 570 TWh/yr of national power demand.
Their report sees renewables as well able to supply all UK power needs, but needing significant storage capacity to balance long lulls in renewable availability. For that, it backs Hydrogen, which it says ‘can be stored at scale in solution- mined salt caverns, for which GB has a much more than adequate potential, albeit not widely distributed’. In addition to large-scale storage, it notes that ‘some fast response storage is needed to regulate grid voltage and frequency’, with advanced batteries being an option, but it says ‘this function, which is costed assuming that it is provided by Li-ion batteries, takes little energy and has a negligible impact on other storage needs’. It says that Compressed air energy storage can help a bit, but ‘could not provide the essential large-scale long-term storage provided by hydrogen’. But adding compressed air would cut the scale of the hydrogen storage needed & could lower the overall cost.
On overall costs it concludes that ‘with only wind and solar supply, supported by hydrogen storage and batteries for grid stabilisation, the average cost of electricity fed into the grid in 2050 ranges from £52 /MWh to £92 /MWh (in 2021 prices), depending on assumptions for the future cost of storage and of wind and solar power, and the discount rate used. The overall average cost is dominated by the cost of the wind and solar supply’. Finally it says ‘constructing the large number of hydrogen storage caverns that will be needed, and the necessary wind and solar capacity, will be challenging. However, Britain is well positioned to meet the challenge, and - guided by a road map - it could be done by 2050 provided a start is made in the very near future’.
So the Royal Society sees hydrogen as a key way forward, whereas , interestingly, it sees large inflexible nuclear plants as likely to be a more expensive way to help balance variable renewables- although it hedges its bets. ‘The addition of constant nuclear base-load supply to a system in which all power is supplied by wind plus solar, supported by storage, will increase the average cost of electricity unless the cost of nuclear power is lower than the cost without nuclear. This will only happen if: the cost of nuclear is at the bottom of the projected range (£66 – 99/MWh); and/or the cost without nuclear is towards the top of the projected [total power cost] range (£52 – 92/MWh).’ But it also says: ‘Adding nuclear could lower the cost of electricity if its cost is at the lower end of current projections, and /or large-scale storage costs are at the top of the range found in this briefing’. Well obviously!
Although few see nuclear costs falling much below the £92/MWh inflation index-linked strike price initially set for Hinkley, depending on what happens when Hinkley starts up fully (in 2030?) and then what happens to Sizewell C: the hunt is still on for private backers. But they may be hard to find. Andy Mayer, CEO of the Institute of Economic Affairs told City AM that ‘outside investors would be mad to back Sizewell. If built, it will be late and obsolete’. Some Small Modular Reactors may be available in the mid 2030s, but no one be can be certain of their viability and costs, especially as grid balancing options. So nuclear is a long shot. We would arguably be better off going for renewables, which can be further expanded now, and storage, which we can also start building up now.
That view has also been taken by a team from Finland’s LUT University who have produced an IET academic paper version of their ambitious 100% renewables energy scenario for the UK (and Ireland). It says that, with on-land wind & PV solar fully used, ‘a transition to 100% renewable energy is economically more attractive than the governmental strategy that involves nuclear power and fossil carbon capture and storage’.
It does note that ‘to reach the ambitious goal of 100% renewable energy in all sectors, a set of technologies for storage, sector-coupling, and flexibility must be applied’, but it says ‘if this is actively targeted, a fossil-nuclear approach that leads to lower levels of sustainability & higher costs can be avoided’. And it looks to a scenario in which ‘the total annualised system costs can decrease to 63 b€, and a levelised cost of electricity of 40 €/MWh, if onshore wind & solar photovoltaics are allowed to be built to a higher extend.’ Well below the bottom of the range quoted by the Royal Society- and that was just for power.
LUT may be over ambitious, but the Royal Society is hardly hair-brained. Nor is the Oxford based Smith School of Enterprise and the Environment, which recently came up with a similarly optimistic study. Perhaps it’s time the UK government started looking seriously at 100% renewable non-nuclear scenarios. In in reply to a recent Parliamentary Question, Green MP Caroline Lucas was to told that ‘the “Modelling 2050 – Electricity System Analysis” publication presents aggregated outputs for thousands of power sector scenarios in 2050 and shows that a range of different technology mixes can achieve Net Zero at similar costs.’ But ‘this work did not look at a renewable only scenario (e.g. wind, solar, and tidal) as this cannot ensure security of supply.’ That’s not good enough - it’s not at all clear that nuclear will be able to provide balancing and security as at low a cost as renewables and flexible storage/ power management systems.
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