The regulators in charge of the American power system expressed concern about the state of the electricity grid as summer approached, cautioning that high temperatures could potentially cause widespread power outages.

However, the grid managed to remain mostly undamaged throughout two of the hottest months on record.

The grid’s surprising stability has no simple explanation — and it offers no guarantees that the utilities will always be able to keep the lights on and air conditioners humming as the climate continues to warm.

Wind turbines, solar panels, and batteries were crucial in supporting the power grid during the hottest days, but traditional sources like natural gas and coal plants still played a significant role. Grid operators and utility companies claim to be better equipped for extreme weather compared to previous years. Additionally, some element of chance also contributed to the success, indicating that future responses to hot summers may not always yield the same results.

Mark Olson, the manager of reliability assessments at the North American Electric Reliability Corp., a national grid watchdog, stated that the grid is currently operating at its maximum capacity.

He stated that this summer was a new and unfamiliar situation for the grid.

There are still a few weeks of summer left on the calendar, but there are already signs of trouble in Florida, Georgia, and the Carolinas. As of Friday, over 120,000 customers were still without power following the impact of Hurricane Idalia earlier this week. This is an improvement from the peak of 500,000 customers without power.

Despite the impact of the hurricane, some regions in the Midwest and Southeast experienced extreme heat as August came to a close. The electricity grid operator for Texas requested that residents conserve energy for six out of the last seven days of the month, while the operator for 15 central states also warned of limited resources. On August 24, the organization responsible for electricity transmission in much of the Midwest declared a state of emergency, calling for additional generators to meet the high demand, but did not implement rolling blackouts.

With hotter summers predicted for the future, additional complications could further burden the electricity supply, such as climate conditions that hinder wind and solar output and spiking power demand from increased use of electric vehicles and electric appliances.

Below are answers to four questions regarding the performance of the U.S. grid during the summer season.

Can we attribute the success to the use of sustainable energy?

While not solely responsible, it has had a significant impact.

In early August, the United States had approximately 237,000 megawatts of solar, wind, and battery storage operating at the utility-scale level. This is a 12 percent increase compared to the previous year, according to the American Clean Power Association. Out of this total, 10,000 megawatts were newly added in the first half of 2023. By the end of 2022, the entirety of the U.S. grid had a capacity of over 1.1 million megawatts.

Given the magnitude of this volume, it is unsurprising that renewable energy is increasingly crucial in maintaining electricity supply. However, advocates argue that the effectiveness of green energy sources is equally important.

According to Gregory Wetstone, CEO of the nonprofit organization American Council on Renewable Energy, it is evident that renewable energy sources, along with supporting technologies such as energy storage, are offering a more durable form of power in response to the growing number of extreme weather events caused by climate change.

Texas currently has the highest amount of low-carbon energy capacity among all states. The Electric Reliability Council of Texas, responsible for overseeing 90% of the state’s power supply, warned before the summer that the grid could face severe disruptions during peak demand if there were outages of 11,000 megawatts from coal, gas, and nuclear power plants.

During the summer, the state experienced power outages ranging from 8,000 to 10,000 megawatts, which was close to the limit. This week, the state surpassed that limit with over 11,000 megawatts of outages. Demand has also been higher than predicted, with at least 10 days setting new record peaks. However, wind and solar energy remained stable and provided up to a third of the grid’s energy needs on certain days.

During times of high demand in ERCOT’s region, one megawatt has the capacity to supply energy to approximately 200 households.

According to John Hensley, the vice president of research and analytics for the American Clean Power Association, wind and solar are effectively collaborating in Texas and other areas. Solar is generating energy during the day while wind power has ramped up during the evening when demand remains high after the sun has set. The addition of battery storage has also contributed to the distribution of clean energy later in the evening.

Grid Status, a website that monitors power grids, reported that this summer, all of the country’s power grids achieved record levels of solar energy production. In late August, during a heat wave, the Southwest Power Pool, a regional grid operator, broke all-time maximum load records for three consecutive days. During peak times, renewable energy sources, mainly wind, contributed between 10 and 20 percent of the total generation.

In the spring, a number of grid operators, including ones in California and the Central U.S., achieved notable accomplishments by setting new records for the proportion of renewable energy supplying electricity demand.

According to Hensley, the significant contribution of renewables this summer should alleviate any doubts or worries about the trade-off between wind and solar power and reliability.

Hensley stated that they are disproving that story.

What portion of this was due to luck?

It is challenging to predict, as grid operators have experienced advantages from seasonal circumstances that may not be reliable in the future.

For example, a relatively temperate spring meant grid operators and asset owners could do routine maintenance on power plants and transmission infrastructure before demand peaked in the hot months. A wet winter meant ample hydropower production in the Northwest and Southwest, allowing California to be confident about adequate power supplies this summer.

The intensity of wind has been particularly high in certain regions of the country, which is not typically expected during a period of elevated temperatures and may become less probable due to global warming.

There are multiple instances when the wind is not blowing.
Previous studies have indicated that climate change may result in stronger winds that could potentially harm wind turbines, transmission lines, and utility poles.

According to Julie Lundquist, a faculty member at the University of Colorado at Boulder specializing in atmospheric and oceanic sciences, there is no definitive agreement on how wind resources will be affected by climate change. Despite this, she emphasizes that wind power will still hold significance.

According to Lundquist, my belief is that wind energy technology will continue to advance and improve. Even if wind speeds decrease, the technology will develop to ensure that wind remains a reliable source of energy in our portfolio. This was mentioned in an email.

According to NERC’s Olson, grid operators who are flexible in their planning and technology updates will be better equipped to capitalize on opportunities that arise. He emphasized that the recent summer season served as a reminder that one can create their own good fortune and reap its rewards.

Clean energy organizations are advocating for new investments to support the grid in order to effectively adapt to changing energy needs. Additionally, increasing the amount of energy storage can assist in mitigating fluctuations in renewable energy production. By investing in transmission infrastructure, regions can collaborate and share resources, reducing their reliance on weather conditions and decreasing the need for fossil fuel power plants.

Wetstone stated that it is difficult to dispute the need for a modernized grid capable of enduring the unpredictable weather patterns of the 21st century.

Can you provide any information about fossil fuels?

It is common for gas and coal power plants, operating at maximum capacity during intense heat, to experience failures. As anticipated, some plants were unable to handle the prolonged hot weather. Despite this, fossil fuels remained a significant source of the nation’s electricity.

Based on information from the U.S. Energy Information Administration, it was found that natural gas continues to be the leading source of electricity in the United States, with a greater proportion than the previous summer. A study by Refinitiv also revealed that gas accounted for 42.4 percent of power from January to mid-August, an increase from 38.9 percent in the same time frame of 2022.

Coal and nuclear were the two most productive sources, with their positions occasionally being switched.

According to Scott Aaronson, the vice president of security and preparedness for the Edison Electric Institute, fossil fuels have proven their value in offsetting the intermittent nature of wind and solar energy during periods of low wind and sunlight. This organization represents utilities.

“It sounds like a talking point when someone says ‘all of the above,’ but we genuinely benefit from an ‘all of the above’ strategy,” Aaronson said. “Each resource has its benefits and drawbacks … but taken holistically, they make for a much more resilient grid.”

As the grid changes, certain specialists and energy suppliers have emphasized the necessity of maintaining fast-start fossil fuel power plants in operation to guarantee dependability.

A report from NERC released in June.

Cautioned about the grid.

I am unable to simultaneously handle the swift closures of coal and gas power plants, as wind and solar energy may not be reliable during severe weather conditions.

The Texas Oil and Gas Association has refuted the idea that renewable energy was responsible for saving the state. In a statement released in August, Dean Foreman, the association’s chief economist, stated that the strong performance of the gas sector highlights its crucial role as the main source of power for the ERCOT grid and as an essential part of modern life.

What other measures can be taken to avoid power outages?

As the year 2023 breaks temperature records, utility companies are preparing for future summers with similar conditions.

Instead of just one or two days where customers heavily use their air conditioning and strain the grid, operators are now anticipating those conditions to last for longer periods of time. They are relying more on strategies like demand response programs, which incentivize customers to decrease their energy consumption during peak hours.

During a period of extreme heat with temperatures surpassing 110 degrees, Arizona Public Service Co., the biggest utility in the state, experienced its highest demand record on seven separate occasions. Justin Joiner, the company’s vice president of resource management, confirmed this information.

Joiner stated that the current situation is not a one-time occurrence, but rather a pattern. As a result, the utility company is taking steps to anticipate increased peak loads and secure additional power reserves in case of emergencies or sudden surges in usage. This includes increasing battery storage and implementing demand response measures.

Certain grids are considering the implementation of virtual power plants, which enable individuals to combine their personal small-scale batteries and electric vehicles to provide power to the grid.

A May report from the Pacific Northwest National Laboratory said that with climate change accelerating, “historical averages may no longer be sufficient for resource planning” and recommended that utilities consider “multiple scenarios … including those outside traditional history-based scenario analysis” to craft plans.

Operators may also have to use independent thinking, as heat waves that span across states can limit the ability to import energy that has typically provided assistance.

According to Michael Craig, an assistant professor at the University of Michigan who specializes in the effects of climate change on energy systems, grid operators must prepare for hotter, longer, and more severe heat waves as a result of climate change. This will lead to more summers resembling the current conditions.

Craig stated that grid operators are implementing significant modifications to achieve decarbonization. However, climate change adds another layer of complexity to these efforts. For instance, there is now a need to consider how to test systems for potential extreme temperatures in the next five or 10 years, rather than just relying on past records.