Read together, the twin reports provide a relatively upbeat picture of expected operating reserves.
Read together, the twin reports — one that describes “Capacity, Demand and Reserves” inside ERCOT, and the other a “Seasonal Assessment on Resource Adequacy” within ERCOT— provide a relatively upbeat picture of expected operating reserves. “With absolute confidence to Texans, the lights will stay on this summer,” said Public Utility Commission chair Peter Lake during a press conference shortly after the reports’ release.
Both reports measure projected operating reserves, or the difference between projected available generation capacity and peak electricity usage. ERCOT expresses operating reserves as a percentage.
The report that focuses on the immediate future — the “Seasonal Assessment on Resource Adequacy” or “SARA” report — shows sufficient generating capacity to serve peak demand during the June-September summer season, assuming normal operating conditions. It also shows sufficient generating capacity under most other operating scenarios it examined.
Assuming normal conditions, the SARA report forecasts operating reserves during the summer at 22.8 percent. It anticipates summer peak demand of 77,317 megawatts (“MW”) and 91,392 MW of resource capacity available during summer peak demand hours. The resource capacity calculation includes 473 MW of planned gas-fired, utility-scale solar and wind capacity additions. Additionally, ERCOT expects to have 2,035 MW of operational battery storage resources, including 283 MW of planned additions.
Released May 16, the SARA report also examined potential extreme scenarios. In one, ERCOT examined how extreme peak consumption combined with an extreme amount of unplanned outages would affect the grid. It found that under such a scenario that generation resources would fall short by 980 megawatts — leading to “load shed” or controlled outages. In another extreme scenario, ERCOT examined what would happen if extreme high peak consumption was combined with extreme unplanned outages and extreme low wind output. In this scenario, generation fell short by 7,756 MW, also resulting in load shed.
Report on Capacity, Demand and Reserves
Released twice annually, the “CDR” report assesses anticipated planning reserves for future years. The newest CDR, also released May 16, examines grid conditions from 2023 through 2032 and shows generally healthy operating reserves going forward. During the summer of 2023, for instance, the CDR shows the reserve margin rising to 36.2 percent. The margin then peaks during the summer of 2024 at 46.2 percent, according to the CDR. ERCOT currently targets a minimum reserve margin of 13.75 percent.
Other highlights of the CDR include:
- The forecasted peak demand for summer 2023 is 79,857 MW and the peak demand during winter 2023-2024 at 66,454 MW.
- The forecasted planning reserve margin of 36.2 percent for summer 2023 is 3.2 percentage points lower than the 39.4 percent previously projected by ERCOT. This decrease is due mainly to generation project delays.
- Planned resource capacity expected for the 2023 summer peak demand totals 13,117 MW. This includes 581 MW of summer-rated gas-fired resources, 834 MW of wind resources, and 11,702 MW of solar resources.
- Developers anticipate adding 4,831 MW of battery storage capacity for summer 2023. This storage capacity is currently assumed to provide grid reliability services (Ancillary Services) for short periods rather than to support customer demand on a sustained basis during peak demand hours.
- The CDR shows solar additions for 2023 at 11,702 MW, and rising to 20,597 MW by 2024.