Here's a neat trick for the energy transition: take some superheated brine from deep underground, use the heat to generate electricity, then extract lithium from that same brine before putting it all back where it came from. That's the closed-loop plan for a California project called Hell's Kitchen, and the company behind it, Controlled Thermal Resources (CTR), is now taking its act to the public markets.

The company is going public through a merger with the blank-check company Plum Acquisition Corp. IV (PLMK). The deal values CTR at a pro forma enterprise value of about $4.7 billion and is expected to raise $300 million in fresh capital. Once the transaction closes—which is anticipated in the second half of 2026, pending the usual shareholder and regulatory nods—the combined company will trade on the Nasdaq under the ticker CTRH.

CTR has been eyeing a public listing since at least 2021 as part of its strategy to develop domestic sources of critical minerals. The centerpiece is the Hell's Kitchen geothermal and lithium project, located in California's Imperial Valley roughly 160 miles southeast of Los Angeles.

The idea is elegantly integrated. "Few projects simultaneously address energy security and mineral security at scale," said Rod Colwell, CTR's chief executive. "Hell's Kitchen is structured to deliver clean baseload geothermal power alongside domestically produced strategic critical minerals from a single integrated brine resource."

On the technology side, CTR plans to use a direct lithium extraction method developed with water treatment firm Aquatech. This approach is meant to sidestep the need for traditional, land-intensive evaporation ponds. The development is planned in phases, combining renewable power generation with lithium production.

The initial construction phase is slated to include a 50-megawatt geothermal power plant and the capacity to produce up to 25,000 metric tons of lithium carbonate per year. The target for first power is 2028, with lithium production expected to follow around 2029. If fully built out, the site could eventually generate up to 650 megawatts of geothermal power and produce approximately 100,000 metric tons of lithium carbonate annually.

But it's not just about lithium. The company is also targeting other valuable minerals dissolved in the brine, including zinc, manganese, potash, rubidium, and cesium—materials that are becoming increasingly important for advanced manufacturing and are often flagged as national security concerns.

CTR isn't starting from scratch. It has already lined up supply agreements with automakers Stellantis and General Motors to provide lithium for electric vehicle batteries, though the final volumes under those contracts could shift as the project develops. On the regulatory front, the project has received a conditional use permit from local authorities and is designated for an accelerated FAST-41 federal infrastructure permitting process. The company says it has raised more than $285 million in private funding and has already invested in long-lead equipment ahead of major construction.

Shares of Plum Acquisition Corp. IV were up 0.19% at $10.54 in premarket trading on Tuesday.