Emerging green unicorns in 2026 look very different from the class of 2021. Gone are the SPAC-fuelled moonshots with no revenue and aspirational timelines. The companies most likely to reach billion-dollar valuations in the next 24 months are those with real customers, real technology deployed at commercial scale, and a clear path to profitability in a world where capital is no longer free.
Larry Fink of BlackRock has argued that the next 1,000 unicorns could be climate tech companies. Whether or not that specific figure proves accurate, the structural case for large-scale value creation in clean technology is compelling. Here are five companies that stand out.
1. Form Energy — Grid-Scale Multi-Day Storage
Form Energy builds iron-air batteries designed for multi-day grid-scale energy storage — the holy grail of renewable energy integration. The technology is proven, the customers are real utilities, and the manufacturing facility in West Virginia is already producing. Iron-air batteries use one of the world’s most abundant materials and can store energy for 100+ hours at a fraction of the cost per kilowatt-hour of lithium-ion at long durations.
Form Energy’s valuation has not been publicly disclosed, but given its Series E funding and utility customer roster, a public listing at unicorn or multi-unicorn valuation is widely anticipated in the 2026–2027 window. The company is arguably the most credible answer to the single hardest unsolved problem in the clean energy transition.
2. Fervo Energy — Next-Generation Geothermal
Fervo Energy applies horizontal drilling techniques borrowed from oil and gas to geothermal energy, dramatically expanding the geography in which cost-competitive geothermal power is possible. A 500 MW project in Utah is underway, and the company has secured power purchase agreements with Google, among others.
Fervo is consistently cited by leading climate tech investors as one of the most likely IPO candidates of 2026–2027. Geothermal provides 24/7 carbon-free baseload power — exactly what grid operators and AI data centers desperately need — and Fervo’s technology dramatically expands the addressable market. The company is backed by Breakthrough Energy Ventures and Congruent Ventures, among others.
3. Sublime Systems — Low-Carbon Cement
Sublime Systems makes cement using an electrochemical process instead of the high-temperature kilns that make conventional cement manufacturing one of the world’s largest sources of industrial CO₂ emissions. Cement accounts for approximately 8% of global carbon emissions — a massive and largely unaddressed decarbonization challenge.
Sublime has secured partnerships with major construction companies and is scaling toward commercial production. As the EU’s Carbon Border Adjustment Mechanism (CBAM) begins imposing real costs on carbon-intensive materials imports from January 2026, low-carbon alternatives like Sublime’s become structurally advantaged rather than merely aspirational.
4. Lilac Solutions — Lithium Extraction
Lilac Solutions extracts lithium from brines using a proprietary ion exchange process that is dramatically faster and cleaner than traditional evaporation ponds — which can take 12–18 months, consume vast amounts of water, and are limited to specific geographies. Lilac’s technology has been commercially demonstrated and works across a much wider range of brine compositions and locations.
As the EV transition accelerates demand for battery-grade lithium, secure and sustainable supply chains become a strategic priority. Lilac is positioned at the intersection of critical materials security and ESG compliance — a combination that is attracting both financial and strategic investors.
5. Heirloom Carbon — Accelerated Mineralization DAC
Heirloom Carbon uses a limestone-based process to accelerate the natural mineralization of CO₂ — a form of direct air capture that is significantly less energy-intensive than the liquid solvent or solid sorbent approaches used by competitors. The company is scaling toward commercial operations in California and has secured advance purchase commitments from Microsoft, Stripe, and other major corporate buyers.
Key stat: The global Direct Air Capture market is projected to reach $1.73 billion by 2030, growing at a CAGR of 60.9% — making it one of the fastest-growing segments in the entire climate tech landscape. (Source: MarketsandMarkets)
Heirloom’s lower energy requirements compared to conventional DAC approaches are critical to its economics — and its commercial viability at the cost levels needed for the voluntary carbon market to support meaningful scale.
What These Companies Have in Common
Each of these five companies solves a large, real problem with a technically validated solution, has early commercial revenue or binding purchase agreements, is backed by credible institutional investors, and operates in a market where regulatory tailwinds are accelerating rather than fading. That combination is the new bar for climate tech credibility — and it separates these five from the class of 2021 that preceded them.
To track private climate tech company development, CTVC publishes regular market intelligence on the sector. For the IPO pipeline specifically, watch SEC S-1 filings and coverage from Bloomberg’s clean energy desk.
Bottom Line
The emerging green unicorn class of 2026 is defined by fundamentals, not narrative. These are companies building real infrastructure, with real customers, in markets where the regulatory and economic tide is flowing in their favor. They’re worth watching — whether as potential investments, as bellwethers for sector health, or simply as evidence that the clean economy is being built company by company.
This is not financial advice. Always consult a qualified financial adviser before making investment decisions.
Read next: Direct Air Capture Companies: The 2026 Investment Case