PJM is leading the way in examining the role of renewables in operating a resilient electrical grid, specifically how much a combination of solar and storage can support the grid during a black start.
Black start units are resources that are able to restore electricity when the grid is down without using an outside electrical supply, and are a basic component of resilience. Resilience is defined by PJM as the ability to plan for, operate through and recover from catastrophic events that are not fully addressed by current reliability standards.
Solar panels, also known as photovoltaic solar (PV), are increasingly used in combination with a storage resource, such as a battery. The battery charges on the solar energy when the sun is shining, and can provide that energy back into the grid when it is not.
The problem is, there are currently no grid-scale PV and storage assets currently performing the black start function in North America; so PJM is still trying to understand their capabilities.
Jonathon Monken, senior director – System Resilience and Strategic Coordination, said PJM is looking to a grant from the National Renewable Energy Laboratory (NREL) to provide some insight.
NREL is the only federal laboratory dedicated to research, development, commercialization and deployment of renewable energy and energy-efficiency technologies. It has some examples of PV and storage being harnessed on a large scale for black start-like functions in Germany, but operational data is very limited.
While there are projects in the United States, they are on a much smaller scale, such as a solar array with a paired battery for a Google data center. None of the U.S. examples are designed for kick-starting the bulk electric system, just keeping a specific facility or two open.
PJM has one of nine Department of Energy (DOE)/NREL grants as part of the Solar Energy Innovation Network, a collaborative research effort administered by NREL and supported by the DOE’s Solar Energy Technologies Office “to develop and demonstrate new ways for solar energy to improve the affordability, reliability and resiliency of the nation’s electric grid,” according to NREL.
The PJM grant is the only one designed to study the viability of solar and storage for black start and resilience. The end game is to see if it is technically possible for a resource of this type to meet the operational requirements for black start resources, which are more stringent than for any other type of generation resource in the PJM Market. This is especially difficult with required run times of 16 hours, often seen as beyond the reach of traditional PV or storage resources.
Black Start a Testing ‘Sweet Spot’
Monken discussed the study at PJM’s Members Committee Webinar Tuesday, in the first of a monthly series of updates on resilience at the webinar. Assessing alternate technology for black start is one of several resilience activities PJM is undertaking.
Monken said that because the black start requirements are easily defined, and black start is a clear function of operational resilience, it is “a sweet spot to do a test.”
One of the reasons this project is so vital, Monken said, is the paucity of data currently available. As a grid operator, PJM is fuel agnostic, but Monken said PJM recognizes the importance of having inherently reliable and diverse fuels. Storage is potentially the fuel-security fix for renewables, because it addresses their intermittent nature and can provide energy when wind or solar can’t.
With increasing parity of solar costs, it is possible to build a 300 MW solar display. But right now there isn’t a combination of PV and storage anywhere that could help black start.
“If you can make renewable fuel-secure, it could open up whole new lines of dialogue and evaluations in our market,” Monken said. “It would change the longer-term plan for renewables and how we integrate them at a regional scale.”
Through the grant, PJM will also identify potential pilot projects. Later in 2019, PJM will narrow the field to the several models of system configurations and performance, then develop the pilot to test solar resources in the field for resilience. “We want to build a model and just try to understand how it would work on our system,” Monken said. “Look at it and say, ‘This is how a system would need to be configured if we have, say, an 80 MW battery and a 300 MW solar array.’”