What’s ‘Resilience’ When it Comes to Power?

The Department of Energy-generated notice of proposed rulemaking at the Federal Energy Regulatory Commission, aimed at rescuing coal and nuclear power generation from the vagaries of competitive markets by raising the idea of paying out-of-market prices for “resilient” generating technologies, rests on the idea of rewarding power plants that have a 90-day supply of fuel on site. The idea is that these plants – coal and nuclear as DOE framed it – are available when other generating technologies – specifically natural gas and renewables – are somehow knocked out during a blackout or other major grid perturbation.

It’s not only a bogus concept from the beginning – blackouts in the U.S. have overwhelmingly been a result of a grid collapse, not generating plant failures – but it ignores a number of other realities about power generation.

In nuclear plants, it matters little that they have more than 90 days of fuel on site if they lose off-site power in an extended blackout. In station blackout conditions, the key is how much battery capacity and diesel fuel the reactors have on hand. How many operating nuclear plants have enough diesel on site to run plant safety systems for 90 days? NRC guidance calls for the ability to run safety systems in the absence of offsite power for “2 to 16 hours,” combining AC battery power and diesel backup. That gives enough time to shut the unit down.

For coal plants, if severely cold weather brings down other generation – not likely but possible – a result could be to freeze the coal pile, regardless of its size. That’s what happened in the 2014 Polar Vortex. Jay Apt, head of Carnegie Mellon University’s Electricity Industry Center, said, “We had coal piles that were frozen shut, conveyer belts to take the coal that wouldn’t move. And parts in the plants that didn’t work at all.”

Another fallacy in the DOE plan is that it ignores important generating technologies that are at least as resilient as nukes and coal, arguably more so. The nation’s most important renewable energy resource is hydro. Hydro plants, conventional and pumped storage, have far more fuel – water – on site than coal plants and even nuclear stations. The DOE proposal appears to have blanked on this reality.


Is this a resilient generating resource?

Is this a resilient generating resource?


In its comments on the proposed rulemaking, the National Hydropower Association said, FERC “should not be focused on specific generating resources, but on the desired regional reliability and resilience services sought. As such, importing requirements specific to one industry may impede the effectiveness of the proposal for which other industries will be eligible.” The NHA comments added, “Hydropower is generally a seasonal resource, with minimal water supply availability known for months, so it is able to meet nearly any duration threshold – with clean, emission free energy.”

Then there is geothermal, where the fuel supply can be measured in geological time. In its comments, the Geothermal Energy Association (GEA) noted that its resources are “not currently deployed in markets within the scope of the Department of Energy’s proposed rule.” But that could change, as western U.S. energy markets are moving toward a wider spread of competitive bidding for supply. The spread of the California ISO’s energy imbalance market is an example.

GEA said that geothermal power “is a renewable technology that can run as a baseload resource while also providing a range of flexible services to the grid. Geothermal provides numerous ancillary services and grid benefits such as power regulation, load following or energy imbalance, spinning reserve, non-spinning reserve, storage and replacement or supplemental reserve. It also offers operational flexibility which assists with integrating intermittent resources, such as wind and solar, to the grid. Geothermal is the kind of resource the DOE proposed rule seeks to help.” In passing, GEA observes, “While fuel security is one important aspect of a potential definition of resilience, it is on its own insufficient to properly incentivize the key services needed for a truly resilient grid.”