As the global energy transition accelerates, clean tech startups are playing a decisive role in reshaping how energy is produced, stored, and managed. From long-duration energy storage to carbon removal and grid optimization, 2026 is shaping up to be a pivotal year for innovation and investment in cleantech.
Here are 10 clean tech startups to watch in 2026, based on their technological potential, funding momentum, and relevance to the energy transition.
1. HELION ENERGY — Commercial Fusion Power (USA)
Helion Energy is at the forefront of private fusion energy development, pursuing a direct electricity generation approach that bypasses traditional steam turbines. Its technology aims to deliver constant, carbon-free baseload power—something renewable sources alone cannot provide.
Why it stands out: While fusion remains high risk, Helion’s technical milestones and long-term power purchase ambitions position it as a bellwether for private fusion commercialization.
2. FORM ENERGY — Solving the Long-Duration Storage Challenge (USA)
Form Energy develops iron-air batteries designed to store electricity for up to 100 hours. This capability directly addresses one of the most persistent challenges in renewable energy systems: managing variability during prolonged periods of low wind or solar generation.
Why it stands out: Long-duration storage is increasingly viewed as a structural requirement for renewable-heavy grids, not a niche solution.
3. CLIMEWORKS — Scaling Direct Air Capture (Switzerland)
Climeworks operates some of the world’s most advanced direct air capture (DAC) facilities, physically removing CO₂ from the atmosphere and storing it permanently underground. Its business model is supported by long-term corporate carbon removal contracts.
Why it stands out: As demand grows for high-integrity carbon removal, Climeworks represents one of the most mature and operationally proven DAC players.
4. AIRMYNE — Reducing the Cost of Carbon Capture (USA)
AirMyne focuses on lowering the energy intensity of direct air capture by using low-grade industrial heat rather than electricity-intensive systems. This approach significantly improves the economics of carbon removal.
Why it stands out: Cost reduction will determine whether DAC can scale beyond early adopters and voluntary markets.
5. TETHER — Software-Driven Grid Flexibility (Sweden)
Tether develops AI-based software that enables electric vehicles to function as distributed energy storage assets. By optimizing charging and discharging behavior, it provides grid operators with flexibility services without new physical infrastructure.
Why it stands out: Digital solutions like Tether’s demonstrate how software can unlock latent value in existing clean energy assets.
6. MOMENT ENERGY — Second-Life Batteries at Scale (Canada)
Moment Energy repurposes retired electric vehicle batteries into stationary energy storage systems. This approach extends battery life cycles while reducing costs and environmental impact.
Why it stands out: Second-life batteries support both grid resilience and circular economy principles, two growing priorities for energy policymakers and investors.
7. RELEAF EARTH — Biochar as a Carbon Removal Tool (Global)
Releaf Earth converts agricultural waste into biochar, locking carbon into a stable form while improving soil health and agricultural productivity.
Why it stands out: Biochar combines measurable carbon removal with tangible local benefits, strengthening its appeal to impact-focused capital.
8. CARBONRUN — Nature-Based Carbon Removal via Rivers (Canada)
CarbonRun enhances the natural ability of rivers to absorb CO₂ by increasing water alkalinity. The process mimics natural geological cycles while delivering measurable carbon removal.
Why it stands out: Nature-based solutions with verifiable climate impact are increasingly attractive as scalable complements to engineered systems.
9. CURA — Decarbonizing Cement Production (Canada)
CURA applies electrochemical technology to reduce emissions from cement manufacturing, one of the most carbon-intensive industrial processes globally.
Why it stands out: Addressing hard-to-abate sectors like cement is critical to achieving net-zero targets.
10. GREEN MANGANESE — Low-Carbon Critical Minerals (Canada)
Green Manganese recovers high-purity manganese from low-grade ores and industrial waste using low-emission processes, strengthening sustainable supply chains for batteries and steel.
Why it stands out: Clean energy expansion depends on access to critical minerals produced with lower environmental footprints.
CLEAN TECH STARTUPS TO KEEP AN EYE ON
The clean tech startups to watch in 2026 reflect a broader shift in the sector: from promise to performance. Investors are prioritizing solutions that can scale, integrate into existing systems, and deliver measurable climate and economic returns.
As energy systems become more complex and capital becomes more selective, these companies illustrate where innovation, funding, and impact are most likely to converge in the coming years.