US geothermal–lithium developer ACR moves toward listing

Steam testing at the site of the Hell's Kitchen geothermal project in Imperial County, California (source: CTR)

Alexander Richter 19 Dec 2025

American Critical Resources (ACR), the developer behind Controlled Thermal Resources’ Hell’s Kitchen geothermal and lithium project in California, has taken a first step toward becoming a publicly listed company in the United States.

ACR announced on December 19 that it has signed a non-binding letter of intent (LOI) with Plum Acquisition Corp. IV (Nasdaq: PLMK), a publicly listed special purpose acquisition company (SPAC). The proposed business combination would result in ACR being listed on a US national securities exchange, subject to a definitive agreement and regulatory approvals.

Bringing a geothermal–lithium developer to public markets

ACR was established by Controlled Thermal Resources (CTR) to develop the Hell’s Kitchen project at the Salton Sea in Imperial County, California. The project combines geothermal power generation with direct lithium extraction from geothermal brines, positioning it at the intersection of renewable energy, battery materials, and critical minerals supply.

ACR will include Stage 1 assets of CTR’s Hell’s Kitchen Project in Imperial County, California, and three additional lithium production facilities, providing a total output of 50 megawatts of renewable electricity and approximately 100,000 metric tons annually of lithium carbonate. across four development stages.

The project has already attracted more than US$285 million in private investment, and CTR has completed a definitive feasibility study for Stage 1, validated by Baker Hughes. The company has also highlighted ongoing research into additional critical minerals present in the brines, including potash, zinc, manganese, rubidium, cesium, and rare earth elements. We reported in September 2025 on a partnership of CTR with BakerHughes.

Why this matters for geothermal and critical minerals

If completed, the transaction would mark one of the most prominent attempts to bring a geothermal-based lithium and power developer to US public markets.

The proposed listing reflects growing investor and policy interest in domestic supply chains for clean energy and critical minerals, particularly projects that can deliver both renewable baseload power and battery materials from a single resource.

Plum IV said the combination is intended to accelerate ACR’s development timeline, strengthen its balance sheet, and provide access to public-market capital to advance projects aligned with US energy security and manufacturing priorities.

Management comments

Rod Colwell, CEO of Controlled Thermal Resources, said the proposed transaction would help unlock the full potential of the Hell’s Kitchen resource after more than a decade of development.

Kanishka Roy, CEO of Plum Acquisition Corp. IV, said the SPAC sees ACR as a company positioned to deliver long-term value by combining renewable energy production with critical minerals development.

Next steps and conditions

The LOI is non-binding, and no assurances have been given that a definitive agreement will be reached. Any transaction would be subject to due diligence, negotiation of final terms, board and shareholder approvals, and regulatory review.

If a definitive agreement is signed, the parties said a registration statement and proxy materials would be filed with the US Securities and Exchange Commission.

Source: company release shared by email