Ramping

Ramping is the adjustment of power generation to match fluctuations in electricity demand and supply for the Bulk Power System (BPS). Traditionally, generation increased and decreased to follow daily consumption patterns as demand rose and fell throughout the day. But growth of intermittent renewables means that variation in weather changes supply—often rapidly—creating at times an additional burden. The term, “net load ramp” considers both changes in renewable output and demand.

With an ever-growing renewable fleet in the Texas Interconnection, hourly net load ramp magnitudes began to exceed 10,000 MW in 2024. Solar and wind each can create large shifts, especially the evening ramp-down of solar in summer months. Rapid consumption shifts occurring at large loads like crypto-currency mines can also impact ramps, aggravating or improving the situation.

Electric Reliability Council of Texas (ERCOT) operators must ensure that the grid remains balanced despite these fluctuations throughout the day and be prepared for potential disturbances. To address these challenges, ERCOT employs advanced forecasting techniques and grid management strategies such as predictive models to anticipate changes in wind and solar output. ERCOT also procures ancillary services based on its consideration of historical and anticipated ramping needs.

ERCOT analyzes each generator’s ramp rate capability to determine sufficiency to meet expected conditions. However, the growing ramp magnitude puts additional stress on traditional thermal power plants. These plants must cycle—ramp up, ramp down, or shut off—more frequently and in larger amounts to accommodate changes in net load. Over time, this cycling can lead to wear and tear on a fleet that has many aging units. Energy storage batteries are proving highly effective in managing ramps, with quick response capabilities, either discharging energy or slowing their charge rate. Large loads can also assist in ramp management, either through scheduling or participation in demand response ancillary services, if they have flexibility in their operations.

The combination of expected demand growth and increasing reliance on renewable energy underscores the importance of ramping in maintaining grid stability. The ability to manage ramping effectively is crucial for ensuring our Region’s reliability, now and in the future.