Reality Check: Keeping the Lights on in Extreme Winter Weather
The key to a more secure grid is not more fossil fuels. Instead, we need to scale up energy efficiency and demand response, expand wind, solar, and batteries, and improve interregional transmission links.
This story was originally published in December 2022. This version was updated to include recent developments.
Winter is here. And this season, as in past years, extreme cold weather threatens the electric system and its ability to keep the lights on. As severe winter weather events become more common due to climate change, electric providers have a heightened responsibility to keep the lights on.
In late December 2022, Winter Storm Elliott made this urgency painfully clear. During the storm, which hit over 20 states from the Midwest across to the East Coast, 13 percent of planned power generation resources in the Eastern interconnection went offline. Bitter cold and heavy snow left more than 6.3 million customers without power at some point over the holiday weekend and over 100 dead.
Elliott is a stark reminder that, as storms grow more intense, building a reliable grid that can perform in even extreme winter weather is imperative.
The Myth
Renewables and the energy transition at large have frequently been used as a scapegoat for winter reliability concerns. And language commonly used to describe fossil resources like “firm” and “dispatchable” make it sound like these fossil power plants can always be counted when we need them.
The Reality
The idea that renewables have caused winter outages has been repeatedly debunked. And in fact, we can’t always count on fossil power plants to show up when we need them most.
Coal and gas plants, for example, made up 73 percent of the capacity of generators that experienced unplanned outages or substantially reduced output during Winter Storm Uri in February 2021.
While no resource is perfect, the reality is that clean energy and demand-side resources have proven track records of both reducing peak demand and keeping the lights on during extreme conditions, while fossil fuels, especially gas, are increasingly showing cracks.
Fossil Fuel Risks
The North American Electric Reliability Corporation (NERC) recently released its 2023-2024 Winter Reliability Assessment that evaluates the preparedness of the grid for winter weather conditions. The report notes concerns about the ability for much of the country — including New England and parts of the Midwest, mid-Atlantic, Southeast, and Texas — to keep the lights on during extreme winter weather events.
The primary winter reliability risks highlighted by NERC relate not to renewables but to fossil generators and the reliability of their fuel supply. Although NERC highlights the rollout of new cold weather reliability standards this winter, it notes that cold weather continues to pose a risk to fossil power plants. Notably, it draws attention to fuel supply risk during extreme, long-duration cold weather events, specifically for natural gas.
To draw attention away from these concerns, fossil fuel advocates are quick to contend that output from renewable energy resources like solar and wind depend on the time of day or weather conditions, and so can’t be counted on for reliability. In fact, grid planners have developed sophisticated approaches to predict and utilize the contributions of renewable resources under many different conditions and in concert with other resources, such as battery energy storage.
However, grid planners and operators have so far failed to apply these same approaches to fossil resources, allowing their reliability to be overestimated. A study from Advanced Energy United suggests that planners may be overestimating gas plant reliability by over 20 percent in parts of the eastern United States, and a similar trend was found in the Texas grid.
The low-hanging fruit for improving winter reliability is to better capture the true availability of fossil resources in the planning process, and fortunately, several grid operators are considering doing so.
Ensuring Winter Reliability
Regulators, utilities, and market operators need to recognize the risks inherent in a fossil-fuel dominated power system and evaluate alternatives to fossil fuels to ensure winter reliability. Fortunately, there are several cleaner, safer, and more effective options:
Energy efficiency and demand response programs (both on the electric and emergingly on the gas side), have been shown to enhance winter reliability by reducing demand during extreme conditions. In other words, programs that invest in home efficiency, such as insulation and heat pumps, have the potential to meaningfully reduce the risk of outages.
Demand response — or calls for energy conservation — was a key tool that grid operators used to help keep the lights on during Winter Storm Elliot. Virtual power plants, made up of networks of electric vehicle (EV) chargers, smart thermostats, home batteries and other IT-enabled devices, enable customers to be compensated for their energy conservation efforts, and even provide backup power to the grid during outages.
Ensuring that the value of these programs is being captured in grid planning and that utilities are evaluating these options properly against fossil resources is essential to unlocking a reliable and affordable grid now and in the future.
Renewable energy. The accelerated expansion of renewable energy and battery energy storage — resources without the fossil fuel system’s cold-weather risks — can support grid reliability when the temperature drops.
However, as our power grid is rapidly approaching its capacity to transport power at the scale needed to keep the lights on (and is frequently pushed beyond its limits during extreme weather events), hundreds of billions of dollars of critically needed new renewable energy projects are currently waiting in line to interconnect and start operating.
There is an enormous opportunity for policymakers, regulators, and utilities to better leverage existing, low-cost solutions to connect clean resources faster and get the most out of our existing grid. Hardware and software solutions known as grid-enhancing technologies act as efficiency upgrades for the grid by, for example, rerouting power flows around congested areas.
Additionally, there is significant untapped opportunity for new clean energy projects to be developed at the sites of retired or retiring fossil generators – which can accelerate interconnection of clean energy resources while bolstering reliability, even as we lose coal and gas capacity.
Transmission. The buildout of regional and interregional transmission, which can allow available excess energy to be transferred to regions experiencing shortages, will allow for existing resources to be more optimally utilized and shared in tight conditions, saving money, improving grid reliability, and keeping the lights on without building expensive fossil fuel power plants.
During last year’s Winter Storm Elliott, for example, isolated local grids in the Southeast suffered outages, while wind resources in the middle of the country were generating more power than could be consumed (known as curtailments). At one point, while the Tennessee Valley Authority (TVA) was experiencing blackouts on December 23, the Southwest Power Pool’s grid experienced about 3 GW of wind curtailments — that’s more energy than TVA’s largest coal plant can produce.
Grid operators, regulators, and policymakers need to continue breaking down the barriers to building new transmission. A pending rulemaking by the Federal Energy Regulatory Commission could improve how transmission is planned and paid for and may be finalized as soon as early 2024. Meanwhile, lawmakers in Congress are deliberating how to streamline the complex and time-consuming permitting process for major transmission lines and are even considering a helpful minimum interregional transmission standard.
Improved reliability standards for all grid resources — including standards for winter weather preparedness and for inverter-based resources — will increase the resilience of our grid in the face of extreme weather. Enforcement of these standards at the state level will lead to more reliable service for ratepayers.
Despite this broad and dependable set of solutions available to support grid reliability, some authorities continue to advocate for fossil fuels to address long-term reliability challenges.
We need a grid that can reliably operate through the winter. But relying on fossil plants and assuming there will be a steady fossil fuel supply is both risky and expensive, especially during extreme weather.
Furthermore, the use of fossil fuels in our power system has become increasingly uneconomic, continues to perpetuate extreme weather through climate change, and creates additional air pollution and negative health consequences for local communities.
Instead, we can achieve better outcomes by leaving behind failure-prone fossil fuel systems, while speeding the transition to more resilient, cleaner energy.
