solar panels and wind turbines at sunset

Beating the Heat: The Summer Clean Energy Records Worth Celebrating

Grid-level data shows that clean energy generation reached new heights across the United States this summer, but blind spots in the data hamper future planning.

This summer has set a load of climate records, but they’re not records worth bragging about. Notably, this summer was the hottest ever recorded, by a “large margin.” Heat waves across the United States shattered local and regional temperature records, while dangerous wildfires in Hawaii and Canada and extreme flooding in the Northeast are just some of the most recent and apparent climate disasters of the season. Experts suspect that climate change may have contributed to the intensity and severity of these events.

At the same time, this summer was also a record-breaker on the clean energy front — offering a glimmer of hope in our fight against climate change and its corresponding extreme weather. Over the past year, data from the website shows, our electricity system has been making substantial progress transitioning away from fossil fuels, all while working to keep the lights on during times of extreme heat. Investments in grid decarbonization are starting to demonstrate their value to utilities in the short term during tight grid conditions, while extreme weather has continued to demonstrate clean energy’s long-term necessity in slowing the climate crisis.

Clean Energy’s Record-Breaking Summer

Earlier this month, cooling demand driven by extreme heat raised electric load in Texas to an all-time September high, triggering emergency alerts from ERCOT, the state’s regional grid operator. Fortunately, battery storage provided record contributions of 2.2 gigawatts (GW), or 3 percent of load, as the sun set and solar generation declined. Experts noted that these contributions “almost certainly” prevented rolling blackouts in the state.

This is just one of many examples of record-setting contributions from clean energy resources helping to keep the lights on throughout the summer. Solar generation records, for example, have been broken in nearly every regional grid across the country:

  • In the regional grids in California and Texas (CAISO and ERCOT, respectively), solar generation met and exceeded record levels at numerous points over the summer, peaking at over 16 GW of solar generation (68 percent of load) on September 6 in CAISO and nearly 14 GW of solar generation (20 percent of load) on August 16 in ERCOT.
  • In the central United States, the MISO regional grid has met and exceeded its maximum amount of solar generation numerous times this summer, peaking at 3 GW (4 percent of load) on September 1.
  • In the East, the PJM grid reached a similar solar record on the same day (3 GW, 4 percent of load).

Even wind energy, which is typically more plentiful in the central United States outside of the summer months, had a record day in July on the SPP grid, which covers several central US states. SPP reached its highest wind generation level ever at 24 GW, or 49 percent of load. And while MISO, PJM, and especially SPP have a long way to go in building out their solar fleets, the trajectory of their solar records creates some optimism in the pace of the energy transition.

A few additional generation records are worth celebrating for two regional grids that track data that many others do not. Thanks to behind-the-meter (BTM) solar, which typically includes residential rooftop solar panels, New England’s grid operator ISO-NE was able to keep the lights on and reduce peak demand during the height of summer. On July 23, while temperatures in the Northeast peaked in the mid-80s, behind-the-meter solar alone generated 5,085 MW of midday energy for the region (28 percent of load) while reducing peak demand. The mark was only 96 MW short of the all-time record for BTM solar in ISO-NE, set in April of this year.

And in California’s CAISO grid, records for charging and discharging of batteries were broken repeatedly. Energy was frequently stored during periods of ample generation and saved to support the grid during the most outage-prone hours after the sun sets.

It’s possible that clean energy could be having an even greater impact than these records suggest, and we just don’t know it. That’s because not all regional grid operators share the same data around clean energy performance. For example, hourly patterns in battery charging and discharging, which together reveal batteries’ reliability benefits, are shared only by CAISO. Further, the reliability contributions of behind-the-meter solar generation are only well-understood for the two regional grid operators that share that information: ISO-NE in New England and NYISO in New York.

Toward Data-Driven Decision-Making

Data beyond what’s reported by most grid operators could help planners further understand the full suite of reliability, resilience, and climate benefits that clean energy resources can provide.

To help plan for and build a more reliable clean energy grid, grid operators, grid planners, and regulators in regional transmission organization (RTO) and non-RTO regions should begin to track and publicize the following data:

  • Hourly generation data from all grid resources, including behind-the-meter resources and demand response programs. Emerging resources can lower peak demand and risk during the hottest summer days. These resources include demand response and distributed energy resources, such as behind-the-meter solar and storage and virtual power plants. However, their impacts aren’t consistently tracked or shared. Anonymized information on hourly demand response and distributed energy resource participation can complement data from supply-side resources and help policymakers, regulators, and grid planners evaluate the economically and technically optimal set of clean energy resources that can maintain grid reliability.
  • Hourly forecast data, including net demand forecast. Understanding not only what is happening in real time but what is forecasted to come is incredibly valuable for reliability planning and can inform demand response operations.
  • More detailed data about charging and discharging of battery storage. Battery storage on the grid is becoming increasingly important for keeping the lights on, and storage is frequently paired with renewable generation sources. More detailed data can help grid planners and analysts understand how storage can be best incorporated onto the grid, how its value can be counted in long-term planning efforts for grid reliability and resource adequacy, and how it can be optimally dispatched during periods of extreme demand.
  • Hourly rates of renewable curtailment. While renewable energy is rapidly expanding, a small fraction of it is lost through curtailment, due either to transmission constraints (e.g., local congestion or lack of interregional transmission) or insufficient storage resources to save that energy for off-peak periods. Only two regional grids (CAISO and SPP) publicize hourly renewable curtailment data today. Having more curtailment data available can help grid planners and customers understand when clean energy can be more fully utilized and where grid investments are needed to enable higher renewable penetration.
  • More accessible data for non-RTO regions. Crucially, data in non-RTO regions is much more difficult to access and aggregate due to the disparate and siloed nature of vertically integrated utilities, which own their own transmission, generation, and distribution assets. Regulators and policymakers in non-RTO regions could require utilities to publish retrospective data similar to the data produced by RTOs.

This summer shattered temperature records — and unfortunately, it’s unlikely those records will hold for long. Climate change and climate-driven extremes are here, but at the same time, the energy transition is finally under way, led by an exponential deployment of renewable energy technologies. Energy data, and public access to it, is key to ensuring our power systems can operate safely and securely despite worsening climate extremes. And with this data, there’s little doubt that we’ll discover even more records worth celebrating.