Britain’s nuclear power stations recorded a 12% decline in their contributions to the country’s energy system over the past month, as outages raised concerns over how long the ageing plants will be able to keep operating. A temporary closure of two of the country’s eight nuclear plants resulted in a double-digit drop in nuclear generation in January, compared to the same period last year. Hunterston B on the west coast of Scotland is temporarily offline after inspections revealed more cracks than expected in the reactor’s graphite cores. The graphite bricks slow down the neutrons in a nuclear reaction, but over years the process changes the graphite’s structure. Reactor 3 at Hunterston has been offline for nearly a year since it powered down in March last year. EDF Energy told The Guardian last May it was “very confident” the reactor would come back online by last November, but the latest estimate is 31 April. The power station’s other reactor is due back on 31 March. However, the company will only be able to restart the plant if the nuclear regulator gives the green light for the safety case presented by EDF. The company also announced this week that it was pushing back the reopening of its Dungeness plant in Kent, due to maintenance related to pipes carrying steam from its boiler. Rather than restarting in late February, Dungeness should now come back in April. Martin Freer, head of nuclear physics at the University of Birmingham and director of the Birmingham Energy Institute, said: “It is clear they are showing their age. When they were originally built they weren’t built to operate as long as they will.” By the time Dungeness is hoped to return, another old plant, Hinkley B in Somerset, will have been taken offline for graphite inspections. Any unexpected rate of cracking found there could lead to a longer outage.
Guardian 3rd Feb 2019 read more »
Closing down Hunterston and Torness, the Scottish nuclear power plants, is likely to substantially reduce the amount of wind power that is currently being forced off the grid. There is controversy surrounding Scottish windfarms being paid ‘constraint payments’ at some times to avoid the Scottish electricity network becoming overloaded. Because it is windfarms that receive the payments, windfarms have, in reports carried by right wing newspapers, been singled out for sole blame for spending money on ‘constraint’ payments. This is despite the fact that it is the nuclear power stations’ inability or refusal to reduce production when the Scottish part of the grid is overloaded which contributes greatly to the problem. This problem of system overload is the reason that the recently completed transmission line linking Wales to Scotland was built. As Jonathan Marshall. Senior Analyst at the Energy and Climate Intelligence Unit put it recently: ‘On top of reducing constraint payments, the link will reduce the cost of accommodating Scotland’s 2.6 GW inflexible nuclear power stations that work most efficiently when operating at full output’. In fact, in addition to increasing transmission line capacity, more decentralised solutions for absorbing increasing renewable generation should get more attention. These include development of local ‘microgrid’ strategies, more emphasis on storage solutions and a real effort to link large-scale heat pumps with district heating networks. The latter, heat pump solution, would also help to turn renewable electricity into heat. When there is too much electricity on the grid the heat pumps can produce hot water which is then stored in large hot water tanks to be used by local residents as is necessary. This is a technology that is being increasingly applied in Denmark.
Dave Toke’s Blog 3rd Feb 2019 read more »