Why did EDF bring forward the planned closure of Hinkley Point B nuclear station? For the ageing UK nuclear power plant, irradiation-caused cracks to structural graphite blocks were an important factor driving the decision. At issue is the interlocking graphite blocks that in the AGR design form the reactor core. Opponents argue that years of irradiation have caused so much damage to the blocks that the plants should be out of operation. This is indeed one of the ageing issues that affects AGRs, but the situation, and the decision on whether to close the plant, is more complicated. On one hand the AGRs are all old enough to have paid off their capital cost, making them more lucrative – and the GB Capacity Market offers tolling payments throughout the winter months, so long as the power plant is available in the event of a capacity alert with four hours’ notice. But on the other hand, ageing may affect the amount of power that can be generated. For example, problems with weld cracking in the primary circuit of several AGRs emerged in the 1990s and they resulted in the regulator mandating that the plants could only operate at 70% of normal power. Nor does operation guarantee profit, especially in a market like that of Great Britain. Even with capital paid off, nuclear has high fixed costs to cover and electricity prices in the GB market have become more volatile. There are low prices – sometimes even negative pricing — on windy and sunny days when renewable sources are at their maximum and the market rewards plants that can respond. Weighing both certain and uncertain revenues against fixed costs has clearly brought Hinkley Point B to the end of the road.
NS Energy 1st Feb 2021 read more »