The Partial Observer by Dennis Higgins

NY Needs To Take a ‘Workable Approach’

Around noon on a sunny day this past April, much of Spain, Portugal, and even a bit of France went dark, as if someone had switched off the lights. What happened?

Solar and wind generate direct-current electricity. But electric grids run on alternating current. (EU grid frequency is 50 hertz (Hz) and the U.S. grid frequency is 60 Hz.) Inverters—fancy switches—convert power from DC to AC and attempt to regulate voltage and frequency on the grid. Clearly, variations in solar or wind output can cause voltage dips or spikes which may prompt inverters to disconnect from the grid. Load imbalances, power demand surges, or frequency fluctuations may also cause inverters to disconnect because deviations can cause equipment failure or lead to power outages.  

The North American Energy Reliability Corporation issued its highest alert to transmission owners, planners, and generator operators, urging an investigation into how deployed inverter-based resources (IBRs) will respond to grid disturbances. 

“Since 2016, NERC has analyzed numerous major events totaling more than 15,000 MW of unexpected generation reduction. These major events were not predicted through current planning processes. Furthermore, NERC studies were not able to replicate the system and resource behavior that occurred during the events, indicating systemic deficiencies in industry’s ability to accurately represent the performance of IBRs and study the effects of IBR on the bulk power system (BPS).”

NERC’s alert references almost a decade of inverter performance failures. IBRs should continue to operate through a power line fault or power plant shutdown, but current inverter settings instead may trigger a complete shutdown. As solar and wind resources supply a larger share of electricity, improper inverter settings increasingly risk cascading failures. But those settings may be locked behind manufacturer-issued passwords.  Many deployed inverters come from manufacturers no longer in business, posing a further challenge in reconfiguring settings. The result? It may be impossible to predict how IBRs will respond to fluctuations in voltage or frequency.

What happened in Spain was not the first such failure. In Odessa, Texas, in 2021, a combined-cycle power plant went offline, triggering shutdowns of more than 1 GW of solar generation. Inverters were operating with settings from a decade earlier. However, in Texas, 56 percent of its electricity came from traditional synchronous generation and a major outage was avoided. At the time of Spain’s event, the grid was powered over 70 percent by solar: A chain reaction of disconnects occurred, blacking out the Iberian Peninsula.

Hydro, nuclear and fossil-fuel power plants have big spinning generators and do not need inverters. A constant speed produces alternating current at a controlled frequency. Slight modifications in rotating speed enable generators to adjust to voltage or frequency changes. As in the song, “big wheels keep on turning”: Spinning generators have lots of inertia, which enables them to power through load changes.

Solar and wind resources have no inertia. There is a large device called a synchronous condenser. It looks like a rotating generator, but instead of producing electricity, it uses energy from the grid to keep spinning. Synchronous condensers add inertia to a grid powered by intermittent resources. Their job in averting grid failure is, in an emergency, to supply voltage for a very brief period. So, if a solution to the fluctuations in voltage or frequency can be determined quickly enough, condensers might help to keep the lights on.

Beyond the panel or turbine price tag, solar and wind need battery backup. Low capacity-factor solar and wind require overbuilding, resulting in a bloated grid. Remote resources must have full nameplate transmission to a three-phase line or substation. New state law, RAPID, is intended to get that transmission built by allowing developers to take land by eminent domain to run poles and wire. Solar and wind need a whole new fiscal model: We must pretend that we can sell our overbuilt solar in the summer and import energy the rest of the year. NERC has indicated that designing a grid whose reliability hinges on imported energy is a bad idea. California dumped three terawatt hours of solar last year and still experiences blackouts when expected imports don’t arrive. As noted by the independent system operator, the NYISO, statewide transmission constraints could last for years: We may find ourselves dumping energy generated at wind or solar resources in western New York even as the metro region experiences outages. And we might want synchronous condensers, bumping initial costs by 10 percent. We must also supply condensers with electricity when the grid is up.  Electric bills will continue to rise as ratepayers buy overbuilt solar and wind resources, thousands of miles of transmission, synchronous condensers, and pay for electricity to keep condensers spinning.

Last year’s Public Service Commission biennial report on the Clean Energy Standard acknowledged that a 70 percent-renewably-powered grid would require installing solar and wind at many times the current rate. In a letter to the governor, the Business Council slammed the energy plan, noting:

“Unrealistic mandates erode public confidence and undermine the state’s ultimate GHG emission reduction goals. It is more important that New York leads by example by taking a workable approach to its energy and emission goals than failing to meet an arbitrary schedule.”

We may still avoid California’s situation; that state is saddled with an expensive grid meant to run on solar and wind but still burning lots of gas, and relying on imports to keep the lights on. We might yet sidestep outages like the one that darkened Spain.

Albany is looking at advanced nuclear. Nuclear generators would require a tiny fraction of the land needed for wind and solar, but would provide thousands of high-paying jobs, and emission-free baseload energy at a 95 percent capacity factor. An efficient, fiscally-sound grid would not rely on intermittent resources and batteries, while full capacity carbon-free baseload backup sat idle. Existing hydro and new nuclear as the backbone of the grid, along with a modest solar and wind component, would economically, reliably, enable us to meet the “100 percent-carbon-free grid by 2040” state target.

Dennis Higgins is a retired math/computer science professor. He and wife Katie run a farm in Otego and, as a family, they are committed to addressing climate change any way they can, including 20KW of solar panels, geothermal heat, all electric appliances, and driving an EV. Dennis has been engaged in regional energy issues for approximately 15 years.