By Anisha Jain
Picture the factory floor of a brewery in Lisbon. Steam coils off copper vats. Every sip of Heineken beer brewed there begins with heat, continuous and relentless, powered by natural gas for over a century. Now imagine that same steam coming from a four-story stack of superheated bricks charged by solar panels sitting outside in the Portuguese sun. No combustion. No emissions. No change to the brewery’s operations at all.
This is not a thought experiment. In November 2025, Heineken, Rondo Energy, and EDP contracted to do exactly that at a Lisbon malting plant, making it the largest heat battery deployment in the beverage industry worldwide.
The Forgotten Quarter
While headlines celebrate falling solar costs and booming electric vehicle (EV) sales, a full quarter of the world’s fossil fuel consumption goes toward heating rather than electricity or transportation. Industrial process heat powers cement kilns, chemical reactors, food processing plants, and steel mills. It is the quiet engine behind almost everything manufactured on earth, and it is much less visible in the clean energy debate.
The reason we hear so much less about industrial heating is structural. The modern clean-energy conversation has been built around electricity: solar panels generate it, batteries store it, electric vehicles consume it. But the factory making your cereal box or your car’s structural framework runs primarily on heat, often above 500 degrees Celsius and sometimes closer to 1,000, far beyond what conventional heat pumps can reliably deliver. Industrial heat powers the physical economy almost invisibly, which may be why it has remained one of the most underfunded corners of the energy transition.
The irony is difficult to miss: after trillions of dollars in climate innovation, one of the hardest sectors to decarbonize may depend on a technology that looks suspiciously like a brick.
Bricks as Batteries
Rondo Energy, founded in 2020 and based in Alameda, California, is solving heating needs with superheated refractory bricks. The operating principle is elegantly simple: use cheap, intermittent electricity from solar or wind to heat bricks above 1,000 degrees Celsius, then release that stored heat as continuous industrial steam on demand, 24 hours a day, without combustion or emissions, and without disrupting existing factory operations.
In October 2025, Rondo announced commercial operation of the world’s largest industrial heat battery: a 100 megawatt-hour (MWh) unit at a fuel production facility in California’s Kern County, powered entirely by a 20-megawatt on-site solar array. It charges during the six lowest-cost hours of sunlight per day and delivers heat around the clock, at a claimed round-trip efficiency above 97 percent. The storage medium? Brick and wire. Materials older than the industrial revolution, repurposed for the new technological revolution unfolding right now.
A month later, Southeast Asia’s first heat battery went live at a cement plant in Thailand. Rondo now operates across five industries on four continents and has raised more than $160 million in funding.
The EV Moment for Heavy Industry
To understand why this matters strategically, consider what happened to EVs. For years they were a niche product: too expensive, too subsidy-dependent. Then solar prices dropped and cheap electricity became even more abundant, manufacturing scaled, and costs crossed a threshold. The economics changed. EVs stopped being purely an environmental statement and started being a rational consumer choice.
Andy Lubershane, a partner at Energy Impact Partners, an investor in Rondo, drew the parallel directly: heat batteries will open up an even larger new market than EVs did, namely industrial heat, which represents a quarter of global energy consumption. The underlying driver is the same: solar is now so cheap in so many places that electricity is essentially free for hours each day. A heat battery is built to harvest that excess power and convert it into something factories can actually use.
The business model innovation is as important as the technology. Rondo’s Heineken partnership runs on a Heat-as-a-Service model: Heineken does not buy the battery. Instead, EDP supplies the solar, Rondo provides the storage, and the brewery receives contracted zero-carbon steam like a utility bill. Capital expenditure risk sits with the infrastructure providers, not the industrial customer. This reduces adoption friction to nearly zero. It is the same logic that moved enterprise software from on-premise servers to the cloud.
The Honest Caveat
The U.S. market has moved more slowly than Europe, partly because industrial electricity rates penalize companies for using cheap, intermittent renewable power. The Trump administration’s cancellation of federal grants for industrial decarbonization in 2025, including planned Rondo deployments with Diageo and Eastman Chemical, has not helped. And while global energy transition investment hit a record $2.3 trillion in 2025 according to BloombergNEF (BNEF), venture capital funding for startups fell for the third consecutive year, a reminder that early-stage industrial bets still carry real risk.
However, physics does not wait for policy to catch up. Solar is getting cheaper every year, and the economics of industrial heat decarbonization will become compelling in more markets regardless of whether Washington is watching.
What to Do With This
For students at Harris or Booth thinking about where policy and market forces converge, industrial heat is a sector where systems thinking, financial modeling, and policy compound. Net Zero Insights reported that industrial decarbonization investment surged nearly 200 percent year-over-year in 2025, a signal that institutional capital is beginning to notice. The companies and institutions that move early will not just reduce emissions. They will capture a structural cost advantage over incumbents still running on gas.
The brick has been keeping us warm for ten thousand years. It turns out it might help cool the planet too.
Reader Question:
If solar electricity is becoming intermittently free in major industrial regions, what other processes beyond steam generation might be unlocked by cheap thermal storage? And who bears the risk of getting the timing wrong?