Dave Elliott: Nuclear plants are designed to run flat out, in part to recoup their large construction costs. Their output can be varied a bit, but this entails thermal stresses and potential safety issues with the build up of active Xenon gas that is released when fission reactions are reduced. It needs time to decay. That limits how often and how quickly the plant can be ramped down and then back up- so as to match changes in energy demand (‘load following’) and the varying output of renewables. So basically nuclear plants are inflexible. So do they have any role for balancing variable renewables? Renewables will continue to expand of course- by 2035 there might be 45GW. But just in case you though that balancing some of that with nuclear might be possible in future, the Hinkley nuclear EPR plant is not scheduled to load follow. And it seems unlikely if any of the other proposed new large nuclear plants (Wylfa, Olbury, Moorside, Sizewell, Bradwell) would do – it would undermine their already precarious economics. Though as now, they may be added to the capacity market, to be there for background support, if that makes any sense. A more cynical view is that, as now, this inclusion is just a way to provide nuclear with an extra subsidy, which, like the rest of the contracted capacity, is paid for by a surcharge on consumers bills.
Environmental Research Web 24th March 2018 read more »