How We Can Keep Cool Without Frying the Grid (Or the Planet)
Deploying smarter next-gen cooling technologies and flexible grids can beat summer heat without breaking the system.
The US power grid is facing another major test. After a massive heat dome settled over the US last week, temperatures pushed into the triple digits across major cities from St. Louis to Boston. In several places, especially in the Southeast and Midwest, high humidity, compounded with extreme heat, is making conditions feel even worse. Once rare, these kinds of extreme humid heat events are now routine, driving electricity demand to historic highs that test the grid just when people need cooling the most.
On June 24, the PJM Interconnection — serving 65 million people across 13 states — hit nearly 161 GW of peak demand, its highest since 2011. That spike, fueled by air conditioner (AC) use amid extreme heat and humidity, came dangerously close to exceeding system capacity. And it’s not just PJM. From Texas to North Carolina, utilities are issuing conservation warnings, and localized outages are becoming more common.
AC keeps homes livable, protects food and medicine, and cools essential infrastructure like data centers and hospitals. But the power systems we rely on weren’t built for this kind of sustained, widespread demand. As heat waves intensify, our growing dependence on cooling systems is straining the grid like never before.
The cooling dilemma
In the United States, ACs are nearly universal — installed in about 90 percent of homes — and their electricity draw is obvious come billing time. In parts of California, ACs can account for 60 percent of peak summer demand in residential buildings. As warming accelerates alongside increased urbanization and population growth, the AC stock in the US is expected to grow to 542 million units by 2050, a 35 percent increase from 2020, putting even more intense pressure on our power systems.
Yet today’s ACs aren’t designed to meet this challenge. The most common units in use are also among the least energy efficient options on the market, often use refrigerants with high global warming potential, and are not optimally designed to tackle a crucial comfort component: humidity. If we continue to rely on current technologies, we risk overwhelming power systems, driving up emissions, and leaving vulnerable communities even more at risk by making air conditioning financially unviable to own and operate.
That’s why we need smarter, more energy-efficient, and more affordable ways to keep cool. Primarily, solutions that can respond to real-world conditions, real-time cooling needs — and help stabilize the power grid.
Humidity: the blind spot in today’s cooling
Most ACs on the market today cool by lowering air temperature (sensible cooling) but are inefficient at managing humidity (latent cooling), leading users to overcool their space to feel comfortable. On the days when heat and humidity conditions are intense, cooling demand spikes, putting stress on the grid and forcing utilities to turn to expensive, and often high-emitting “peaker” plants. In 2021, the United States had nearly 1,000 peaker plants, most fueled by natural gas, according to a US Government Accountability Office analysis.
As warming accelerates, high humidity may become the tipping point that pushes some US regions beyond their limits, intensifying risks to both human health and the power grid as cooling demand surges. When wet bulb temperatures approach or exceed critical human survivability thresholds — typically around 35°C (95°F) (though some studies suggest impacts may begin several degrees lower), the body can no longer cool itself through perspiration. At that point, maintaining livable indoor conditions becomes not just a matter of comfort, but a vital necessity for human safety.
Super-efficient ACs to the rescue
One solution is rethinking ACs themselves. A new class of super-efficient ACs — using high-efficiency components and designed and optimized for real-world conditions — can deliver better dehumidification and comfort while using 60 percent less energy than today’s common models.
During extensive prototype field testing in Palava City, India these units maintained consistent comfort (below 27°C/80.6°F and 60 percent relative humidity) even in extreme conditions; and they cut peak demand by up to 50 percent. Palava’s climate closely resembles that of Florida and other tropical/sub-tropical US states, making these ACs highly relevant for hot, humid US regions where cooling demand strains the grid.
While these working prototypes have so far been demonstrated in India, the similarity of climate profiles in many parts of the world makes a coordinated push from manufacturers, standard setting bodies, large buyers, and governments essential to bring them to market and into homes in the United States and worldwide. Their potential to significantly reduce peak load could play a critical role in improving grid stability and strengthening energy security — especially during recent extreme heat events.
VPPs in the efficiency puzzle
Super-efficient ACs can significantly reduce energy demand, but what if the energy system itself could also adapt in real time to changing conditions?
To keep grids resilient in the face of extreme heat, we can leverage the resources already in our homes and businesses. That’s where virtual power plants (VPPs) come in. VPPs provide the grid with “demand flexibility” during heat waves by coordinating thousands of devices — like smart thermostats, batteries, and EVs — to shift or reduce electricity use during peak demand, acting as distributed power plants.
In some VPPs, smart thermostats are harmonized to keep temperatures stable while easing grid strain by adjusting set-points and operating times; in others, EVs or batteries can act as distributed generators – providing energy at times when cooling is most needed. In these ways, VPPs can help meet growing cooling demand while reducing reliance on costly, polluting peaker plants, and rewarding customers in the process. For instance, APS in Arizona offers a one-time $50 credit to enroll in its VPP, and annual credits to continue to participate. Some VPPs are also resilience assets for households: configured so that batteries or EVs can provide backup power during outages.
Momentum is building: last year, utilities in 34 states and Puerto Rico took action to initiate or expand VPPs. We estimate that by 2030 these and other demand response initiatives could serve an estimated 60 GW of demand in the United States — at a fraction of the time and cost of a new gas-fired power plant. These aren’t just cost-saving solutions, they’re vital tools for resilience against growing climate shocks.
Thinking outside the window box: cooling innovation
Startups are also advancing a broader wave of cooling innovation. Within Third Derivative, RMI’s climate tech accelerator, portfolio companies like Blue Frontier, Transaera, and MIMiC Systems are reimagining how we manage heat and humidity. Blue Frontier uses liquid desiccants to reduce AC energy consumption significantly; Transaera developed a sponge-like material that removes humidity before cooling; and MIMiC applies solid-state thermoelectric technology to cooling that eliminates refrigerants and moving parts. Meanwhile, companies like Barocal, Pascal, and Exergyn are rethinking air conditioning through novel materials and compressor-free, refrigerant-free systems that could dramatically reduce power demand. Together, these technologies point to a future where cooling is not only more efficient, but also smarter, cleaner, and better suited to a warming world.
What’s next?
We shouldn’t have to choose between comfort and security. We already have the technology to deliver cooling without overwhelming our power grids or accelerating climate-warming emissions. Super-efficient air conditioners and other innovations, paired with dynamic grid solutions like VPPs, offer a feasible pathway to expand access to cooling while slashing energy use, emissions, and costs. All that’s needed now is a collective effort to scale these solutions.
