Chicago firm CashEnergy pitches lime‑pellet long‑duration heat storage, cites Anchorage pilot and rural use cases

Arpit Duvetti, founder and CEO of CashEnergy, told the Alaska House Energy Committee on Feb. 27 that his company has developed a long‑duration thermal energy storage system based on heated calcium hydroxide pellets that can be charged with excess electricity and discharge heat when communities need it.

The technology, Duvetti said, “is kind of rechargeable” and combines features of a solid fuel and a battery: the material stores heat chemically when dehydrated and releases heat when it reabsorbs moisture. “I like to call the solution as coal without the consequences,” Duvetti said, adding the system can reach temperatures “up to 1,000 Fahrenheit.” He described a summer pilot in Anchorage and an ongoing public demonstration that drew policy makers and energy leaders.

Why it matters: committee members pressed for technologies that can address Alaska’s high heating costs, seasonal demand swings and reliance on diesel and declining natural gas supplies. CashEnergy described an approach intended primarily for heat—district or building heat, water‑system thawing and other thermal loads—rather than direct short‑term electricity storage, and emphasized lower capital cost compared with lithium‑ion batteries.

How it works and the Anchorage pilot: Duvetti said the company thermally charges calcium hydroxide (derived from limestone) at roughly 300°C to dehydrate it, producing a stable, solid pellet. To extract heat, operators expose the pellets to controlled moisture vapors; that exothermic reaction releases heat without the combustion risks associated with fossil fuels. Duvetti said the company has operated a pilot in Anchorage and opened the unit to more than 100 visitors as an “open house” demonstration. He also described a year‑long outdoor test in Illinois showing the charged material retains stored energy when physically contained despite exposure to weather.

Scale, cost and logistics: Duvetti described a typical demonstrator sized at about 100 kilowatts (roughly enough for about 50 homes) and said capex for that unit so far is “a few hundred thousand dollars.” He said, by his estimate, the company’s storage capex would be roughly one‑third the upfront cost of an equivalent lithium‑ion installation when scaled for thermal applications, though CashEnergy targets heat rather than electricity. For seasonal storage, Duvetti said a full 40‑foot shipping container of pellets would amount to about 25 megawatt‑hours of stored thermal energy. He also noted that because lime is inexpensive, transportation costs are a major driver of delivered price and argued for local pellet manufacturing once a critical customer base exists in Alaska.

Safety, cycling and maintenance: Duvetti told the committee the chemistry does not create a thermal runaway; the pellets top out near 1,000°F and the reaction stops. On cycling, he said mechanical breakdown of pellets into finer material can occur after a few hundred cycles (which he equated to roughly two years of daily cycling), at which point the material would be reformed into pellets at a maintenance cost he estimated at about $40 per ton.

Potential Alaska deployment sites and partners: Duvetti said CashEnergy is engaged with utilities and communities including Chugach (referred to in testimony as “Shugach”), Kotzebue and Anchorage for building‑heat or waste‑heat recovery integrations. He listed investors and partners including Halliburton and said the company has Department of Defense and DOE awards and that it won the U.S. Department of Energy Energy Innovation Prize and a first prize event at the White House.

Committee questions and concerns: lawmakers asked about ideal community size, operational details and failure modes. Duvetti said the company sees a practical lower economic limit around 100 kW for community installations and that use cases with seasonal excess renewable energy (for charging) and high diesel heating costs are most attractive. He described a leasing option to lower up‑front risk for communities and said the system is flexible for partial or bulk discharge: “You could just discharge 10% of that and save 90% for tomorrow or winter,” he said.

What remains unresolved: estimates for delivered cost to specific Alaska communities, the timeline for local pellet manufacturing, and the exact status of partnerships with Alaska utilities were described as ongoing or “early stage.” Duvetti said some of CashEnergy’s projects do not rely on federal tax incentives, but many projects in the sector could depend on credits authorized by the Inflation Reduction Act; he told the committee the industry is watching how tax‑credit funding flows into projects.

Ending: CashEnergy told the committee it is ready to deploy more demonstrations and invited further local engagement; lawmakers encouraged follow‑up with utilities and officials to assess pilot sites and regulatory considerations.