Monday, March 8, 2021

Despite Big Demand Swings, Grid Operators Have Kept the Power on During the Pandemic

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During the COVID-19 pandemic, nearly all grid operators around the world have successfully managed substantial changes in electricity demand

Consider this thought experiment: It’s peak load on a hot summer day in Pennsylvania, with generators operating at near capacity to serve more than 31 gigawatts of demand. The state’s electricity demand suddenly drops to nearly zero and then returns to 31 gigawatts several minutes later. How would grid operators handle this hypothetical scenario? In India earlier this year, this was more than a thought exercise. In a televised address on April 3, Indian Prime Minister Narendra Modi asked Indians to switch off their lights and illuminate candles for nine minutes at 9 p.m. on April 5 as a show of national solidarity during the COVID-19 pandemic.

Recognizing that a large, swift reduction and recovery in electricity demand could threaten the reliability of electricity supply, India’s grid operators spent the next two days preparing for the event. They ramped down India’s coal-fired power plants and ramped up hydropower plants to full capacity before the event, with the rationale that hydropower output could be adjusted much more quickly during a sudden demand swing. As Indians began turning off their lights at 9 p.m., operators relied on the flexibility of the generation fleet to ride through the event. Despite the event’s unpredictability and scale, no major outages occurred.

India is not alone. During the COVID-19 pandemic, nearly all grid operators around the world have successfully managed substantial—albeit less severe—changes in electricity demand. Between March and May, operators in the United States, Europe, the Middle East, Australia, and Latin America shared their demand data with EPRI. Based on this information, EPRI has monitored and analyzed trends in grid operations and shared the results with the global power industry and other stakeholders.

“In many regions with strict lockdowns, weekday loads suddenly looked like weekend loads, and operators quickly shifted to running the grid as they would during the weekend,” said Eamonn Lannoye, an EPRI expert on grid operations and markets. “Weekends also had lower demand than normal, often looking like holiday weekends.”

During lockdowns, demand in New York City, Italy, Spain, India, and China’s Hubei province dropped by 20–40%. Closures in the commercial sector drove the reduction in New York City while industrial sector restrictions drove the swings in Italy, Spain, and China.

“For decades, grid operators have planned for a wide range of scenarios so that they have ‘wiggle room’ to adjust operations during unexpected events,” said Lannoye. “They went into this pandemic with the tools, training, and experience to quickly react to big changes in demand and supply. Fortunately, the demand reductions occurred in the spring for the northern hemisphere and the fall for the southern hemisphere. The grid is generally easier to manage during these seasons because the demand peaks are relatively small.”

In areas such as California and the United Kingdom, a combination of low demand and high levels of solar and wind production resulted in extremely low net loads and challenging voltage conditions on transmission grids. Operators mitigated these problems by adjusting the amount of power that various generation facilities were feeding into the grid. The California Independent System Operator curtailed solar and wind generation. In the United Kingdom, the National Grid Electricity System Operator created a service that enabled control rooms to curtail production from generation facilities outside of traditional electricity markets.

“Grid operators got a ‘fast-forward’ glimpse at what typical operations may look like in five to ten years, when very high levels of solar generation are expected to result in considerably lower net loads on the grid,” said Lannoye.

A Look Ahead

There were higher residential peaks on some distribution systems last summer, and a possible contributing factor was the increased number of people working at home during the day as a result of the COVID-19 pandemic. “The precise impact of the pandemic is uncertain because there were other potential contributing factors, such as very high temperatures and wildfires,” said Lannoye. “EPRI plans to examine this issue more closely.”

The pandemic has highlighted how uncertainties can impact energy supply and demand. According to Lannoye, grid operators will increasingly need to integrate risk-based methods to guide dispatch, scheduling of generation, and other aspects of operations.

“Risk-based methods involve building a deeper understanding of the range of possible outcomes in various situations,” he said. “They can be used to quantify uncertainties in forecasts of load and solar and wind generation—and to reduce those uncertainties by improving forecast methods.”

For several years, EPRI has been working with power companies to develop and test grid operational tools that use risk-based methods. EPRI researchers also are examining how energy resources connected to the distribution grid (such as rooftop solar and electric vehicle batteries) can be used in emergency conditions when the transmission grid needs support in maintaining a balance between demand and supply.

EPRI Leads Global Energy R&D for a Post-Pandemic Future

Virtually every energy company on the planet is wrestling with how to best meet customers’ energy needs during the pandemic and prepare for an uncertain future. This uncommon level of industry alignment presents a unique opportunity to benefit from EPRI collaboration.

EPRI has worked with thousands of utility staff with expertise in generation, transmission and distribution, the environment, and end-use customers to identify the need for and scope of four key research areas to address near- and long-term pandemic challenges:

  • Building a more resilient and flexible grid
  • Ensuring employee health and safety
  • Meeting customers’ changing energy needs
  • Creating a cleaner energy future

Learn more about EPRI’s COVID-19 R&D

Lead image: During the COVID-19 lockdown in New York City, closures in the commercial sector drove significant reductions in electricity demand.

Key EPRI Technical Experts:

Eamonn Lannoye
For more information, contact