The lack of flexibility of nuclear power plants in the UK is instrumental in forcing the National Grid to turn off large amounts of wind power when there is too much electricity on the network, adding to consumer costs, a new report has found.
Newly formed advocacy group 100percentrenewableuk found that, based on data provided by energy consultancy Cornwall Insights, in 2017, 94 per cent of the windpower that was turned off could have been generated had nuclear power plant not been operating. In 2019, 77 per cent of windfarm output which was turned off (constrained) could have been generated had the nuclear power plant not been operating.
The irony is that it is wind power operators who receive political blame (from anti-wind groups) because they are paid money (added to consumer bills) to turn off.
This is despite the fact that  it would cost a lot more to induce the nuclear power stations to reduce their generation. Wind farm compensation payments in 2017 were close to £100 million ($180 million), and around £130 million in 2019. Changes to wind power operation to accommodate the inflexibility of nuclear power is associated with nearly all of this compensation to wind farm operators.
The problem is focussed in Scotland where most of the electricity production is either from wind power or nuclear power, with wind power now providing the majority of electricity on an annual basis.
The study by Cornwall Insight, to estimate how much of the practice of turning off wind farms could potentially have been avoided if nuclear power plants were able to operate as flexibly as wind farms, that is, in being able to turn off production when required by the grid, or when they were shut down.
Two years were selected for the study; 2019 as the most recent completed calendar year, and 2017 the most recent year when both nuclear plants in Scotland (Hunterston B and Torness) were fully operational.
Of the two years, in 2017, when most nuclear power was being generated, almost all of the constrained wind generation could have been avoided if nuclear power plant had operated flexibly, or shut down. Nuclear power was responsible for turning off a higher proportion of ‘turned off’ (constrained) in the year when there was more nuclear generation.
Essentially, cheaper electricity production from windfarms is being turned off in order to protect production from nuclear power plant whose production is much more expensive to manage. These nuclear plants either cannot or will not help to balance the grid in these circumstances. This undermines renewable energy and increases the costs to the consumer of operating windfarms. . This means that nuclear power is a poor means of balancing wind power.
This has a big lesson for countries who are building up their renewable energy and who are developing their electricity networks to be flexible to cope with variability of supply. The more nuclear power that is built, the more difficult network management becomes.
In Australia some have suggested that nuclear power can provide more reliable power. The British situation suggests that will not be the case since Australia now has a lot of renewable energy generations.
This pattern of the failure of nuclear power in the UK to participate effectively in grid balancing has been entrenched in the system of contracts awarded by Government to new nuclear and renewable energy generators.
These include Hinkley Point C (nuclear) and new offshore windfarms. The nuclear power plant are only going to get built on the basis of being paid very high guaranteed prices for their generation yet these prices that will be paid even if wholesale power prices drop below zero. Meanwhile the renewable companies are being given contracts which mean they will be paid nothing if the power prices becomes negative.
This is a biased and distorting set of arrangements. These contracts further insulate the inflexible balancing position of new nuclear power and will pass the hidden costs of nuclear inflexibility onto wind and solar farms.
100percentrenewableuk is calling for the idea of providing so-called ‘baseload’ through large centralised generators including nuclear power and fossil fuel power plant to be scrapped in favour of a 100 per cent renewable energy system.
Under this system renewable energy should not be constrained but instead stored using various techniques to provide power through both short and long term storage techniques. Then the stored energy can be used to provide energy when demand is higher and/or there is less renewable energy supply.
A full version of the report can be obtained from the website 100percentrenewableuk.org. Dr David Toke is Director of 100percentrenewableuk. He is also Reader in Energy Policy at the University of Aberdeen, Scotland, UK.
