Wood Mackenzie Analysis Shows Rising U.S. Electricity Demand Pushes Grid Operators To Adapt With Storage, Market Reforms And Infrastructure Upgrades

Rising electricity demand in the United States is creating new challenges for grid operators, who must balance supply and demand, manage regional power flows, upgrade infrastructure, and adapt to the growing role of battery storage. Recent insights from power market discussions and analysis by Wood Mackenzie highlight how major grid operators are responding to these changes and what trends are shaping the market. One key example is Electric Reliability Council of Texas (ERCOT), which has seen rapid growth in battery storage capacity. Since 2024, installations have increased by 124%, reaching 17.3 gigawatts (GW), the highest among U.S. independent system operators.

Despite electricity demand in ERCOT remaining relatively stable, with peaks around 60 GW, battery activity has changed significantly. Storage output has grown from under 100 megawatts (MW) to nearly 300 MW during peak discharge periods. However, battery behavior does not always align perfectly with grid needs.

Maximum battery discharge coincides with both peak demand and high real-time prices only about 25% of the time. Individually, battery output matches peak demand about half the time and aligns with peak pricing roughly 30% of the time. Still, in about 70% of cases, these factors occur within an hour of each other, showing that batteries are generally responsive to market signals, even if not perfectly synchronized.

A notable example of misalignment occurred during Winter Storm Fern. As the storm approached, battery output followed rising demand trends. But as conditions worsened and prices increased, battery activity remained limited, likely anticipating even higher price spikes. When those spikes did not materialize, batteries discharged later, at a time when demand and prices had already dropped.

In the Northeast, ISO New England (ISONE) recently completed the first year of its Day-Ahead Ancillary Service Initiative (DASI), which replaced the earlier forward reserves system. This change is designed to ensure reliable supply as renewable energy becomes more prominent and market revenues become less predictable.

Another important development is the changing relationship between PJM Interconnection and Midcontinent Independent System Operator (MISO), two of the largest power markets in the eastern United States. Historically, PJM exported electricity to MISO, particularly during periods of high wind generation. However, recent trends show increasing power flows in the opposite direction, from MISO into PJM. These shifts are largely driven by price volatility and supply constraints. For example, during a period of high demand in PJM, several gigawatts of electricity were imported from MISO, even as MISO itself faced reduced wind generation. This led to price spikes in both markets until additional generation came online in PJM.

Looking ahead, this trend is expected to continue and even intensify. Rising electricity demand, especially from data centers, is projected to push PJM’s peak demand to around 200 GW by 2040. At the same time, the retirement of thermal power plants, particularly coal, is expected to tighten supply margins. Planned transmission upgrades in the Midwest will also make it easier for electricity to flow between regions.

Overall, these developments point to a more interconnected and dynamic power system in the United States. While new technologies like battery storage are improving flexibility, they also introduce new complexities. At the same time, evolving market structures and interregional dependencies mean that grid operators must continuously adapt to ensure reliability and efficiency in a rapidly changing energy landscape.