A new report from the Colorado Public Utilities Commission is sounding alarm bells on the reliability risks posed to the state’s grid as wind and solar continue to replace fossil fuel plants.
According to Colorado Public Radio:
Heat waves and freezing temperatures won’t be the only risks for Colorado’s power grid in the future, state regulators say. The state’s electricity supply could also be threatened during days when sunlight and wind are nowhere to be found.
A new report released by the Colorado Public Utilities Commission Wednesday highlighted challenges the grid faces as utilities move away from fossil fuels and toward renewables — and as climate change worsens throughout the West.
Currently, the biggest strains to the system in Colorado and other western states are during days of stifling heat or paralyzing cold, research analyst Nicholas Garza, the author of the report, told commissioners Wednesday. As more solar projects and wind turbines are brought online, the main concern will be long periods of still, overcast weather.
“What we would think of as very benign or very boring weather, where you have just persistent cloud coverage and really no wind, that’s actually going to pose the most significant threat,” Garza said.
The report notes that these periods are more likely to occur during future winters when high-pressure systems bring cold weather with long stretches of high overcast and low wind. Adding to the risk is the expectation that an increasing number of the state’s residents will be reliant on electric space heating to keep warm as natural gas furnaces are phased out. That increased electricity demand, combined with unpredictable supply, is creating headaches for the state’s energy regulators, who have long been used to planning for dependable generation from fossil-fuel plants.
From the report:
Increasing penetrations of renewable and energy-limited resources add complexity to a system that utilities in the 20th century initially built with firm generation resources whose
availability was largely independent of weather variability.
Ultimately, the PUC’s researchers find that clean dispatchable generation is paramount to avoid a future where a little mild weather is enough to topple the state’s electric grid.
Climate change and extreme weather elevate the importance of meteorological forecasting for wind and solar and the operational considerations for managing sudden changes in resource availability (i.e., wind ramps). Traditional resource adequacy planning relied on the predictability of fossil generation, and load and system reliability did not suffer. Using historical weather data to analyze future resource adequacy needs may not fully capture all of the risks, given the effect weather has on both system load and resource availability. For long-term resource adequacy planning, flexible resources, such as storage and demand response, and clean dispatchable generation, like geothermal and hydropower, will be required to manage demand variability.
Colorado is not alone in facing this ticking time bomb. Balancing authorities across the country are raising concerns over rising reliability risks as dispatchable generation continues to be retired and replaced with intermittent renewables.
In Texas, the Electric Reliability Council of Texas (ERCOT) is warning that the state’s grid is still vulnerable to blackout risks during severe winter weather despite having implemented several reforms following the 2021 Winter Storm Uri debacle.
According to Utility Dive:
“Year to year we are developing more generation resources. The majority of those resources being added to the ERCOT grid tend to be renewable resources, like solar and wind,” ERCOT President and CEO Pablo Vegas said on Tuesday. Those resources do not perform as well in the winter, he said, explaining the reserve margin decline.
Likewise, the New York Independent System Operator (NY-ISO) has voiced similar concerns about the growing capacity of weather-dependent renewables displacing dispatchable gas-fired generation. The ISO says the status quo leaves perilously little room for error on high-demand days over the next decade. It also notes that emissions restrictions on existing gas generation are making matters worse.
The New York Independent System Operator warned Wednesday of narrower margins to maintain power grid reliability over the next 10 years as gas-fired generators are retired and buildings and transportation are increasingly electrified.
New York’s electric grid is a summer-peaking system, but is projected to become a winter-peaking system in the mid 2030s, due primarily to electrification of space heating and transportation, NYISO said. The New York statewide grid is expected to be reliable in the winter for the next 10 years, “but will be stressed under gas supply shortage conditions that can occur during cold snaps,” the report said.
The expected drop in reliability margins in New York City is due primarily to the planned unavailability of simple cycle combustion turbines to comply with the state Department of Environmental Conservation’s Peaker Rule that cuts emissions from peaking plants on the hottest days of the year.
With increased renewable intermittent generation to reach the climate law’s goal of 70% renewable energy by 2030, at least 17,000 MW of fossil must be retained to continue to reliably serve forecasted demand, the reliability assessment said. Beyond 2030, dispatchable emissions-free resources will be needed to balance intermittent supply with demand.
It’s time for policymakers to get serious. A grid susceptible to turmoil due to a little cloud cover and low wind is no way to power a state. Reliable generation matters, as does a sense of pragmatism regarding clean energy policy.
The report on Colorado’s future, and the ongoing experiences of grid operators across the country, show that an energy transition focused solely on marginalizing fossil fuel plants in favor of wind and solar is not a sustainable strategy. If we’re ever to achieve maximum buy-in from the public in the quest to confront climate change, people must be assured that their quality of life will not suffer as the grid gets cleaner.
These next few years will be a time for choosing for Colorado lawmakers, PUC regulators, and the state’s electric utilities. Do we place a premium on grid reliability, or are we beholden to just two renewable resources? Do we proceed with caution in the energy transition, or do we go forth with reckless abandon?
We can have our cake and eat it too. We can gradually meet the challenge of climate change by tactfully decarbonizing the economy with minimal disruptions to the quality of life that Coloradans have become accustomed to.
The technologies to do it exist. We just need the will to follow through.