New report highlights grid threats from US retirements

Friday, 15 June 2018

The study, conducted by international consulting firm ICF, found that a disruption to natural gas pipelines would have a major, prolonged effect in the Midwest and Mid-Atlantic regions if nuclear power plants are not available as a back-up source. Those regions are served by the PJM Interconnection regional transmission organisation (RTO), which has previously said that it does not expect the closure of four nuclear power plants in Ohio and Pennsylvania to adversely impact the reliability of its transmission system.

The ICF report says that such an event could result in the loss of nearly 27 GW of gas-fired generation, with 18 GW serving the PJM Mid-Atlantic area, depending on the severity and location of the event.

"When combined with the retirement of a similar amount of nuclear capacity, the analysis implies such an event would put as much as 22% of the area's load at risk of being shed in the highest load hours," it said.

According to the report, a gas pipeline disruption lasting 60 days would see the PJM service area experience "load losses" of more than 200 hours across up to 34 days, with over 45% of the affected gas-fired capacity having no back-up fuel capability.

The preservation of nuclear power plants would successfully mitigate the risk of electricity service disruptions, the study shows. Under its Policy Case scenario, in which nuclear power plants continue to run thanks to prudent state and federal policies, nuclear plants would be able to compensate for the losses in natural gas generation due to an unexpected interruption over a 60-day period.

Some natural gas plants can run on oil as a back-up fuel for a few days, but most natural gas plants rely on a steady supply of fuel delivered via pipelines, the NEI said. Nuclear power plants are able to hold a long-term supply of fuel on-site.

The US Federal Energy Regulatory Commission earlier this year launched its own proceeding to examine the resilience of the US grid. It did so after terminating proceedings on a proposed rulemaking on grid resilience and reliability from Energy Secretary Rick Perry that would have recognised the attributes of generation sources able to store fuel on site, such as nuclear. US President Donald Trump recently directed Perry to take immediate action to stop the loss of "fuel-secure power facilities", including nuclear power plants that are facing premature retirement, from the country's power grid.