Apr 9, 2024 · 40m · green-blueprint
The rise of heat batteries
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
Host Stephen Lacey interviews Rondo Energy CEO John O'Donnell to explore how brick-based thermal heat batteries utilize cheap, intermittent renewable power to decarbonize global industrial heat. The episode details the thermodynamic advantages, grid balancing synergies, drop-in boiler economics, and federal policy initiatives driving the commercial adoption of thermal storage.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. How this is scored →
The hosts as informed peer 5.6 Guest teaching 2.9 Guest disagreement 0.9 The hosts pushing back 0.7
speaking balance: gold is the hosts, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 21:25 Critique of developer fixation on hydrogen
O'Donnell dismisses US developer enthusiasm for hydrogen subsidies as chasing speculative projects that sell hydrogen to somebody somewhere sometime instead of deploying commercially proven thermal storage.
Hardest push from the hosts ▶ 22:07 Challenging optimism against past thermal technology failuresLacey directly challenges O'Donnell's high optimism, pointing out how solar thermal was once equally hyped before being completely wiped out by PV manufacturing economics.
Biggest teaching moment ▶ 6:35 Explaining the grid emissions penalty of electric boilersO'Donnell educates Lacey on why baseload electric boilers can double or triple industrial scope 1 and 2 emissions on today's grid by driving peak thermal generation demands.
The host holds their own ▶ 31:16 Detailed historical mapping of DOE Earthshot milestonesLacey showcases deep sector literacy by comparing the Sunshot PV cost benchmarks and direct air capture targets to the 2035 Industrial Earthshot goal.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The hosts as informed peer | Guest teaching | Guest disagreement | The hosts pushing back | Why |
|---|---|---|---|---|---|---|
| Clean Energy Cycles and the Lessons of Solar Thermal | 6 | 1 | 0 | 0 | Stephen Lacey delivers an extensively researched historical overview of clean energy cycles from Bush-era hydrogen to 1980s solar thermal troughs. John O'Donnell provides commentary on his previous startups OSRA and Glasspoint, emphasizing the harsh lesson of avoiding excessive innovation. | |
| The Industrial Heat Challenge and Episode Introduction | 5 | 4 | 1 | 1 | Lacey categorizes competing industrial decarbonization routes including electric boilers, heat pumps, and hydrogen. O'Donnell explains the thermodynamic and grid penalties of continuous baseload electrification while detailing Rondo's brick-based thermal storage mechanics. | |
| Drop-In Industrial Replacement and the Economic Tipping Point | 5 | 3 | 1 | 0 | Lacey probes the specific equipment heat batteries replace and the historical barriers preventing industrial adoption. O'Donnell details drop-in boiler replacements and highlights how recent negative electricity pricing hours enable operating costs below fossil fuel combustion. | |
| Grid Synergies, System Modeling, and Developer Partnerships | 6 | 3 | 1 | 1 | Lacey queries how to scale project deployment through large developer partnerships versus bespoke industrial sales. O'Donnell shares data from Jesse Jenkins showing system-wide carbon multiplier effects and notes European utility engagement outpaces the US developer focus on hydrogen subsidies. | |
| Long-Term Market Sizing and Global Decarbonization Horizon | 6 | 3 | 1 | 2 | Lacey presses O'Donnell on why heat batteries will succeed when past solar thermal technologies failed against PV cost declines. O'Donnell explains how cheap intermittent PV directly feeds heat batteries to address 90% of global industrial heat demand without chemical conversion losses. | |
| Federal Policy Support and Industrial Earthshot Targets | 6 | 2 | 1 | 1 | Lacey draws direct comparisons between the DOE Sunshot program and the Industrial Earthshot target to slash emissions 85% by 2035. O'Donnell validates the feasibility based on sub-2-cent renewable generation contracts and federal first-of-a-kind deployment funding. | |
| Managing Grid Load Growth and Power Generation Repowering | 5 | 4 | 1 | 0 | Lacey asks how heat batteries address rapid load growth from manufacturing and data centers. O'Donnell illustrates an unexpected market application: repowering industrial cogeneration plants and partnering with combined-cycle thermal power stations to provide firm clean baseload generation. |
Statements from this episode (21)
O'Donnell: In 2005 Solar Thermal Produced Most Solar Power at Lower Cost Than PV
“At the time, this is back in 2005, solar thermal delivered most of the world's solar electricity. It was far lower cost than PV.”
O'Donnell: Electricity Moves 1,000 Miles While Steam Moves 1,000 Meters
“We learned that you can move electricity a thousand miles, you can move steam a thousand meters.”
O'Donnell: High Cost of Capital from Over-Innovation Kills Renewable Projects
“If you are too innovative, if you can't turn to a standard construction company or EPC, if you can't bring a new technology with suitable guarantees to market, cost of capital that's too high will just kill any renewable energy project.”
O'Donnell: Industrial heat consumes 25% of global fossil fuels
“It's a quarter of all the coal, oil, and natural gas that we burn in the world is for industrial heat.”
O'Donnell: Global industrial heat represents a massive 9,000-gigawatt addressable market
“The IEA says we built more than half of the solar industrial heat that's running in the world, but it was a drop in the bucket. I mean, literally .3 gigawatts out of a 9000 gigawatt market.”
O'Donnell: Intermittent solar and wind are the cheapest energy in history
“PV and wind are pretty much everywhere in the world, intermittently cheaper than any other form humans have ever had available, including burning fuel.”
O'Donnell: Carbon capture fundamentally requires burning 30% more fossil fuels
“One, the carbon capture path says you're burning fossil fuel, burn 30% more fossil fuel than you're using right now to capture the emissions from burning fossil fuel. We can stipulate that is not a pathway that's cheaper than burning fossil fuel.”
O'Donnell: Electric boilers double or triple emissions on today's US grid
“A heat pump may get you about level with emissions from burning fuel directly locally, and an electric boiler will multiply your scope one plus two, at least by a factor of two and maybe three.”
O'Donnell: 1,000°C bricks match lithium-ion energy density at one-tenth the cost
“And when you heat a brick to a thousand C, it stores as much energy per pound as a lithium ion battery. Costs 10 times less, lasts 10 times longer.”
O'Donnell: Steam boilers represent over 80% of US industrial heat
“The race to scale is boilers everywhere. Just go replace that. That's something like 80% of industrial heat. It's more than that in the United States.”
O'Donnell: South Australia experiences nearly 3,000 hours of negative electricity prices
“Look at South Australia with 70% renewables in the system and almost 3000 hours a year of negative electricity prices.”
O'Donnell: Rondo heat batteries cost $5/kW marginally at 98% efficiency
“A round of heat battery is not a 2000 dollar or 1000 dollar a kilowatt electrolyzer that delivers heat at 50% efficiency. It's about five dollars a kilowatt on a marginal basis for these electrical wire heaters, and it's 98% efficient at turning electricity in…”
O'Donnell: Heat batteries unlock up to 1.9 times their capacity in renewables
“Jesse Jenkins has, is publishing a paper shortly exploring that. His paper findings really excited us because he found that in looking at systems that he modeled in the east, eastern side of the U.S., for every megawatt of heat batteries that show up in the sy…”
O'Donnell: Heat battery grid carbon savings double project-site savings
“And those grid effects of causing more renewables to show up that the heat battery is not using all those megawatt hours mean that the total system carbon savings are approximately twice the savings at the project site.”
O'Donnell: US developers are dangerously distracted by speculative hydrogen subsidies
“In the U.S., there's a developer community's attention, in my humble opinion, has been a bit attracted to the hydrogen subsidies, and that The place will get the next wave of growth for utility-scale solar. We'll be building hydrogen projects that sell hydroge…”
O'Donnell: Electrolyzers do not pencil below 50% capacity factor
“Electrolyzers that in principle can operate intermittently, but because of their capital costs, they don't pencil operating at capacity factors typically below 50%.”
O'Donnell: Rondo heat batteries address 90% of global industrial heat
“The temperatures that today's Rondo heat batteries deliver serve about 90% of all the industrial heat used in the world.”
O'Donnell: Path is clear to decarbonize industrial heat within 15 years
“We see the path clear with what we're doing to decarbonize most of that within about 15 years, given the constraints on how fast wind and solar can be built, and there aren't meaningful production constraints on the brick materials that we use.”
O'Donnell: Intermittent renewable power will economically eclipse fossil fuels globally by 2030
“By 20 30 in most of the industrialized world, the conditions that exist in the six European countries where we're developing projects now in Australia and the half dozen US states, those market conditions exist in most of the industrialized world that you can …”