US nuclear generation reaches a short-lived high – EIA

While a number of nuclear power stations in the US have shut down in the last decade, the combined impact of added capacity through power uprates, as well as shorter refuelling and maintenance cycles, have allowed the remaining plants to produce more electricity. In 2018, US nuclear power output totalled 807.1 TWh – a fraction higher than the previous peak of 807.0 TWh reached back in 2010.

At the start of this year, there were 98 operational nuclear reactors at some 60 plants across the US. Two of these units – Pennsylvania’s Three Mile Island and the Pilgrim nuclear power station in Massachusetts – are expected to close later this year. The last nuclear power station to come online in the US was the Tennessee Valley Authority's Watts Bar Unit 2 nuclear power reactor, which has a capacity of 1.2 GW.

According to project information reported to the EIA, only two new nuclear reactors are scheduled to come online in the coming years. Georgia’s Vogtle Units 3 and 4 will begin generating power in 2021 and 2022, respectively, and will provide 2.2 GW of generating capacity. But this new capacity will not offset the plant closures planned for the next seven years. By 2025, US nuclear capacity will fall by 10.5 GW following the closure of 12 reactors, says the EIA. 

The US nuclear fleet has only been able to maintain electricity generation near 800mn MWh for the past ten years because several plants commissioned uprates, or modifications to increase their generating capacity. The EIA measured 2.0 GW of thermal power uprates between 2010 and 2018. 

In addition, nuclear plants have reduced the time that they are out of service for refuelling or maintenance. Last year, the average nuclear reactor outage in the US was 25 days. The plants typically refuel every 18 to 24 months and annual fluctuations in power output are often attributed to maintenance cycle alignments across the fleet. 

By 2025, the EIA expects electricity generation from nuclear plants to fall by 17%. However, the organisation believes this loss in production will be offset by output from new natural gas, wind and solar facilities.