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Climate Tech Hardware Startups
Climate tech startups in the HardwareMap index that build hardware: storage, geothermal, fission, fusion, hydrogen, carbon capture, heat pumps.
by the HardwareMap editors3 min read
From the HardwareMap index, REV 26.09, refreshed 3 Oct 2026
Contents
Climate tech startups that build hardware number 17 in the HardwareMap index energy category as of REV 26.09: grid and home storage, industrial heat, geothermal, fission, fusion, hydrogen and carbon capture. This page lists each with HQ hub, stage, disclosed capital raised and status. Sorting rule: what the hardware does for the grid or the plant, then disclosed funding. It sits under the hardware startups index.
The table is live, drawn from the same records as each company datasheet. Climate-relevant companies in other categories, such as electric vehicles in mobility, are listed there instead.
How we group climate tech startups
- Storage. Batteries and heat stores that shift clean power in time.
- Firm clean power. Geothermal, fission and fusion that run around the clock.
- Molecules and carbon. Electrolyzers, CO2 conversion and direct air capture.
- Buildings. Heat pumps and home energy.
Disclosed capital raised orders the names inside each group. "Raised" means disclosed equity only; grants, loans and project finance are excluded.
Storage climate tech startups
Form Energy (Somerville, Massachusetts) builds iron-air batteries that store power for about 100 hours by reversibly rusting iron. It builds them on the former Weirton Steel site in West Virginia. Its first commercial deployment, a 1.5 MW / 150 MWh system with Great River Energy in Cambridge, Minnesota, broke ground in August 2024 (Form Energy).
Base Power (Austin) installs batteries at homes for backup and runs them together as a virtual power plant. Base owns the hardware, so homeowners avoid the upfront cost. EcoFlow (Shenzhen) sells portable power stations and home storage.
Industrial heat is the other storage market. Antora Energy (San Jose) stores electricity as heat in carbon blocks, then delivers it as heat or as electricity through thermophotovoltaic cells. Rondo Energy (Alameda) builds heat batteries sized from 2 MWth to over 100 MWth per unit.
Firm clean power: geothermal, fission, fusion
Fervo Energy (Houston) applies horizontal drilling and fracturing from oil and gas to build geothermal reservoirs in hot rock. Its index record notes that Cape Station in Utah began delivering power in 2026, the year it listed.
Oklo (Santa Clara) designs Aurora, a compact sodium-cooled fast reactor, and plans to own the plants and sell the power, with data centers as key customers. Radiant Industries (El Segundo) builds Kaleidos, a helium-cooled microreactor that fits in a shipping container; its first test unit shipped to Idaho National Laboratory in 2026, per its index record.
Four fusion companies complete the group: Commonwealth Fusion Systems, Helion Energy, Proxima Fusion and Marvel Fusion. Their claimed timelines are quoted with dates in fusion companies.
Hydrogen, carbon and buildings
Sunfire (Dresden) manufactures SOEC and alkaline electrolyzers for hydrogen. H2Pro (Caesarea, Israel) builds electrolyzers that make hydrogen and oxygen at separate times, designed to connect directly to renewables. Twelve (Berkeley) converts captured CO2 into jet fuel and chemicals and opened AirPlant One in Moses Lake, Washington, in June 2026, per its index record. Climeworks (Opfikon, Switzerland) builds direct air capture plants that pull CO2 from the air for permanent storage.
In buildings, Quilt (Redwood City) makes ductless heat pumps with room-by-room control, designed to replace gas furnaces.
Climate hardware outside the energy category is filed by what it is. Carbon Robotics (Seattle) builds the LaserWeeder, which kills weeds with AI-aimed lasers instead of herbicides, and sits in robotics. Slate Auto (Troy, Michigan) is building a low-cost electric pickup, and Arc (Los Angeles) builds electric boats; both sit in mobility.
What the index shows about climate tech startups
- Firm power and storage split the capital. Commonwealth Fusion Systems and Fervo Energy hold the two largest disclosed raises; Base Power and Form Energy, both storage, hold the next two.
- Factories come early. Form Energy in West Virginia and Antora in San Jose build their own hardware rather than outsource it.
- Investors repeat. Breakthrough Energy Ventures appears in the investor lists of Form Energy, H2Pro and Rondo Energy.
Climate hardware is slow to scale, so funding stage matters more than in software. See hardware startups by funding stage, the wider deep tech startups list, and the investors in deep tech VC firms. The next REV adds new entries and marks status changes here first.
Continue with Battery Startups: Chemistry, Stage, and Who Is Shipping Cells.
Frequently asked questions
How many climate tech startups are in the HardwareMap index?
The energy category of the index holds 17 climate tech hardware startups as of REV 26.09, covering storage, geothermal, fission, fusion, hydrogen, carbon capture and heat pumps. Electric vehicle makers, farm robots and other companies with climate benefits are filed under their main categories, such as mobility or robotics, so a wider count of climate-relevant hardware in the index is higher.
Which climate tech startup has raised the most?
Commonwealth Fusion Systems has the largest disclosed raise in the energy category at about $4 billion. Fervo Energy follows at about $3.2 billion, then Base Power at $2.5 billion. Outside fusion, storage and geothermal draw the most capital. These figures are disclosed equity rounds only, and the index does not count government grants or project finance as raised.
What is climate hardware?
Climate hardware is physical equipment that cuts or removes emissions: batteries, heat storage, reactors, geothermal wells, electrolyzers, capture plants and heat pumps. It differs from climate software because each unit has a bill of materials, a factory and a field installation. That makes it slower and more capital intensive to scale, and also harder for a competitor to copy quickly.
Are any climate tech startups publicly traded?
Two companies in the energy category are listed as public in the index: Oklo, which designs small fast fission reactors, and Fervo Energy, which listed on Nasdaq in 2026, according to its index record. Several fusion companies outside the index have also reached public markets by merger; the fusion companies note covers them. This is a record, not investment advice.
Is nuclear power counted as climate tech?
In this index, yes. Fission and fusion both produce electricity without direct carbon emissions, so Oklo, Radiant Industries and the four fusion companies sit in the energy category next to storage and geothermal. Readers who disagree can filter them out: each company datasheet carries tags such as fission or fusion, and the table on this page can be read without those rows.
HardwareMap catalogues climate tech startups that build hardware. Open any company above for its datasheet, or browse the energy category.
The index
All 219 startups, filterable by category, hub, stage and funding.