How the Grid is Bracing for Summer: Insights from the 2025 Stress Test

Why Summer Poses a Unique Grid Challenge 

Summer is the season of maximum energy demand—and minimum margin for error. When temperature extremes collide with aging infrastructure, the real question isn’t whether our system will be tested, but whether it can withstand what’s coming. 

What the 2025 NERC Summer Assessment Tells Us 

Following last year’s record-breaking heat, the North American Electric Reliability Corporation’s (NERC) 2025 Summer Reliability Assessment predicts a risk of electricity supply shortfalls during periods of more extreme summer conditions, and that risk is already being felt. In June, the season’s first major heat wave swept across much of the U.S., bringing record-breaking temperatures and high humidity from the Midwest to the Northeast. To meet peak electricity demand, the grid must deliver reliability today, while adapting to meet the evolving needs of tomorrow. 

At the same time, the industry report projects a 10 GW increase in peak electricity demand between 2024 and 2025, more than double the increase from 2023 to 2024. The demand is being driven by economic growth and increased industrial and data mining loads, the latter of which requires 24/7 power reliability. And while the assessment focuses on North America, recent blackouts in Spain and Portugal offer a stark reminder that extreme weather doesn’t just strain demand. It can destabilize grid infrastructure itself. 

Aging Infrastructure and the Real-Time Test Ahead 

The last 10 years are the warmest on record globally, but much of the energy infrastructure in use is more than a decade old. Weather is just one of several pressure points—along with supply chain constraints, generator outages, and fluctuations in renewable output—that could turn this summer into a real-time system stress test. It’s a measure of our readiness, resilience, and willingness to act on what the data already makes clear. How we respond will determine whether our grid emerges stronger and more adaptable for the challenges ahead. 

“Energy reliability is more than avoiding blackouts. It’s maintaining the quality of life people expect, 24/7.” – Xiufang Gao, Director of Energy Transition Market Strategy at Mitsubishi Power 

The Impact of Capacity Retirements 

While headlines tend to focus on clean energy targets and emissions goals, a more technical but equally urgent challenge is quietly unfolding behind the scenes: the steady retirement of dispatchable generators. Since September 2024, over 7.4 GW of installed, dispatchable generator capacity has retired or become inactive, reducing the energy system’s flexibility to respond to peak conditions, NERC reports. 

During the late June heat wave, for example, PJM Interconnection, the grid operator for much of the Mid-Atlantic and Midwest, hit a peak load of 161 GW, nearly 5% above forecast, and relied on almost 4,000 MW of demand response to stabilize the system. “Some of our systems really came close to the edge,” said Federal Energy Regulatory Commission Chairman Mark Christie, speaking in Utility Dive. 

As aging assets near the end of their operational life, they tend to become less cost-competitive against newer equipment and experience higher forced outage rates. They can also require overhauls that take them out of service for extended periods of time—often in the summer due to limited pre-seasonal maintenance availability. As more units retire without timely replacement, on-demand generation capacity declines, contributing to shrinking reserves and greater reliability risks. 

Upgrading Legacy Assets: Hydrogen-Fueled Innovations 

In parallel, upgrades to existing assets are showing what’s possible and paving the way for future-ready systems that offer both dependability and a lower carbon footprint. Hydrogen-capable gas turbines are emerging as an innovative pathway. In June, Mitsubishi Power and Georgia Power demonstrated 50% hydrogen fuel blending on a retrofitted advanced class gas turbine at Plant McDonough-Atkinson—the first of its kind. The upgraded unit had been converted the previous year to enable hydrogen blending, setting the stage for increasingly carbon-free, utility-scale power generation. 

Tests like this one demonstrate how forward-looking modifications to legacy equipment can support cleaner, more flexible power and complement the broader transition underway. Mitsubishi Power Americas President and CEO Bill Newsom has put it this way: “We need to provide electrons today, with a clean path forward.” 

The Role of Battery Storage and Renewable Pairing 

Solar and battery deployments are playing a bigger role meeting summer demand and responding to variability, but their performance depends on careful orchestration, not just capacity. NERC’s latest report notes the addition of 13 GW of new battery storage coming online. Combined with solar, these additions are expected to provide over 35 GW in summer on-peak capacity. 

“Pairing battery storage with renewables requires the right equipment and a system that is seamlessly coordinated and responsive enough to deliver power exactly when it’s needed.” – Gao

In Texas, California, and across the U.S. West, the influx of battery energy storage systems (BESS) has improved the ability to manage energy risks during challenging summer periods. BESS resources maintain their charge during the day and can help fill gaps caused by late-day drops in solar output—particularly in late summer, when shorter daylight hours reduce generation. 

Effectively deploying battery storage often means designing for regional realities. In California, that might mean emergency backup for public services; in Mississippi, it could mean reducing curtailment of excess solar. Prevalon Energy, a Mitsubishi Power Americas company, has supported both—demonstrating how storage can flex to meet grid-specific challenges. 

“Some argue that pairing battery storage with renewables makes them dispatchable—that batteries fill in when the sun is not shining or the wind is not blowing,” says Gao. “But translating that theory into real-world performance is more complex. It requires the right equipment and a system that is seamlessly coordinated and responsive enough to deliver power exactly when it’s needed.” 

Using Natural Gas to Meet Peak Demand 

Alongside digital and renewable advancements, maintaining reliability during periods of peak demand requires agile resources. Natural gas remains the most flexible tool in the energy mix, particularly in the summer when speed and dependability are at a premium. 

At CERAWeek 2025, U.S. Secretary of Energy Chris Wright emphasized its continued relevance and impact, noting that, “Natural gas today supplies 25% of global primary energy and has been the fastest growing source of energy over the last 15 years.” Few resources can match its combination of fast ramping and proven scalability, especially as we transition to a cleaner, more complex grid. 

Natural gas offers dependability, flexibly responding to fluctuations in output from energy resources like solar and wind. For instance, in the Northwest, precipitation is expected to be lower than average, limiting hydroelectric generation availability. Pairing natural gas with demand-side management can help offset that shortfall. 

According to the U.S. Energy Information Administration, natural gas-fired generation hit record levels last summer. With demand rising again, supply constraints are a real risk. NERC recommends that natural gas power plants and gas companies maintain clear lines of communication to support electric grid reliability. This coordination is especially important during late spring and early summer, when pipeline systems often undergo maintenance. 

“The question is not if something will go wrong, but whether the system and its operators are prepared when it does.” – Gao 

Preparing for Summer Stress: A Strategic Planning Outlook 

This summer's test will underscore the need for strategies that balance near-term dependability with long-term transformation. A reliable power supply requires approaches that bridge seasonal risk, support dispatchability, and adapt to an evolving resource mix. For those planning, investing, or operating at the grid edge, the priority is clear: be ready before the pressure hits. 

“The question is not if something will go wrong, but whether the system and its operators are prepared when it does,” says Gao. “That challenge isn’t unique to North America. We’re seeing it across the globe.” 

Grid planners today must plan around extremes, not averages. In the face of rising volatility, energy decision-makers need solutions that are clean, resilient, flexible, and fast to deploy. This is what the world increasingly depends on. And it's why those working across the energy sector must see themselves as more than operators or planners. They’re in a position to be a positive force for change in a world that relies on power every hour of every day. 

Explore our takeaways from other industry reports: 
Understanding the Realities of Hydrogen – (IEA’s Global Hydrogen Review)