The ERCOT battery fleet surpassed another dispatch milestone earlier this week, sending over 5.5 GW to the grid on Monday evening. The figure below displays the net output of the fleet along with Hub real-time prices. The real-time price profile, shown as the gray dots, was ideal for battery operators. Real-time prices across the hubs dipped to $0/MWh for several hours in the middle of the day with abundant solar generation. This provided cheap charging opportunities for the battery fleet. Then the grid tightened in the evening as solar disappeared and demand peaked, causing real-time prices to shoot as high as $300/MWh. With many ERCOT batteries now participating in capturing real-time energy arbitrage (see ‘All Signs Point to Arbitrage’), the response from the fleet was dramatic as dispatch followed the higher prices and peaked along with the real-time prices.

Figure 1 | ERCOT Battery Fleet Net Dispatch and Hub Real-Time Price

Monday’s new record dispatch marks the fourth time a new record has been set this year and the third time in this month alone. Before Monday, the fleet had barely reached the 5.0 GW mark so the new mark in the sand was quite the jump, increasing by 0.6 GW. As the fleet continues to grow, we expect this spring and summer will offer more opportunities for the ERCOT to continue to show dispatch growth. With mild demand and high solar generation, springtime tends to provide premium charging opportunities with low midday prices while tight evening ramps in the summer often lead to premium dispatch opportunities.

Figure 2 | Running Maximum of ERCOT Battery Fleet Dispatch (MW)

The figure below shows the ERCOT fleet’s arbitrage opportunity by hub and is displayed in our ERCOT Daily Battery Dashboard. The TB1st represents the arbitrage available to a battery that dispatches during the highest priced hour of the day and charges during the lowest priced hour of the day. The TB2 average represents the arbitrage for a 2-hour battery that dispatches for the two highest priced hours of the day and charges during the two lowest priced hours. Most batteries in ERCOT are 2-hour batteries. On Monday, the TB2 average for a Houston battery was over $165/MWh, more than six times higher than the previous day’s arbitrage opportunity and twice as high as the monthly average so far this March. The other hubs saw similar TB2 averages with the Houston hub taking the lead while the South hub trailed behind at $160.43/MWh. If you’re not already subscribed to our ERCOT Daily Battery Dashboard, you can contact us for more information.

Figure 3 | TBNth RT Arbitrage Values ($/MWh)

The changing of the season and the strength of ERCOT solar will lead to more days like this Monday in the coming spring and summer seasons with big opportunities for battery real-time arbitrage. With a growing fleet that is participating regularly in the real-time energy market, the new dispatch record is unlikely to last long. If you’d like to keep track of the ERCOT fleet’s growing capacity, you can subscribe to our Monthly US Renewables Dashboard. For all things battery-related, make sure to stay up to date on our battery reports, including our essential, evergreen, and market tracking reports.