Top 10 Energy Startups to Watch in 2026

Amidst the dynamic energy sector, key startups like Fervo Energy and Helion Energy are pioneering technological advancements. Driven by increased investment and policy support, these innovators are shaping the future of sustainable energy solutions. Here’s a deep dive into the transformative forces at play.

Published: February 18, 2026 By Aisha Mohammed, Technology & Telecom Correspondent Category: Energy

Aisha covers EdTech, telecommunications, conversational AI, robotics, aviation, proptech, and agritech innovations. Experienced technology correspondent focused on emerging tech applications.

Executive Summary

The global energy sector is undergoing its most transformative period in decades, with startups raising unprecedented capital to tackle climate change, grid modernization, and the surging power demands of artificial intelligence infrastructure. According to Fortune Business Insights, the global energy storage market alone is projected to reach $546 billion by 2030. From next-generation geothermal and nuclear fusion to AI-powered grid optimization and gravity-based storage, these ten startups represent the most consequential companies reshaping how the world generates, stores, and distributes energy. This analysis profiles each company individually, examining their technology, funding, market positioning, and strategic significance for the energy transition.

Key Takeaways

Combined funding across the top 10 energy startups exceeds $12 billion, reflecting massive investor confidence in the energy transition
Crusoe Energy leads with a $10B+ valuation after its $1.375B Series E, bridging AI infrastructure with stranded energy
Nuclear fusion and advanced fission represent the largest capital concentration, with Commonwealth Fusion Systems and Helion Energy raising a combined $5.6B
Long-duration energy storage is emerging as the critical enabler for renewable grid integration
The AI-energy convergence is creating an entirely new category of energy startups focused on powering compute-intensive workloads

Top 10 Energy Startups — Ranked Summary

Rank	Company	Focus Area	Total Funding	Headquarters
1	Crusoe Energy	AI Data Centers / Stranded Energy	$1.375B+ (Series E)	Denver, CO, USA
2	Commonwealth Fusion Systems	Nuclear Fusion (Tokamak)	$2.9B total	Cambridge, MA, USA
3	Helion Energy	Magneto-Inertial Fusion	$2.7B total	Everett, WA, USA
4	Fervo Energy	Enhanced Geothermal Systems	$1.5B (Series E)	Houston, TX, USA
5	Form Energy	Iron-Air Battery Storage	$405M (Series D)	Somerville, MA, USA
6	Oklo	Advanced Fission Microreactors	Public (NYSE: OKLO)	Santa Clara, CA, USA
7	Radiant Industries	Portable Nuclear Microreactors	$150M+	El Segundo, CA, USA
8	Energy Vault	Gravity-Based Energy Storage	Public (NYSE: NRGV)	Lugano, Switzerland
9	Proxima Fusion	Stellarator Fusion Reactors	€130M (Series A)	Munich, Germany
10	H2Pro	Green Hydrogen Production	$75M+	Caesarea, Israel

1. Crusoe Energy — Powering AI With Stranded Energy

Crusoe Energy has emerged as the most valuable energy startup in the world, achieving a valuation exceeding $10 billion after closing a $1.375 billion Series E round in October 2025. The Denver-based company operates at the intersection of two of the decade's most powerful trends: artificial intelligence and energy transition. Crusoe builds and operates AI data centers powered by stranded, wasted, or renewable energy sources — including flared natural gas that would otherwise be burned into the atmosphere. The company reports that its approach delivers 30-50% lower energy costs compared to traditional hyperscale data centers while significantly reducing carbon emissions. Crusoe's power pipeline now exceeds 45 gigawatts, and the company has become a key infrastructure partner in OpenAI's massive Stargate project. With projected revenue approaching $1 billion in 2025, Crusoe represents a new category of energy company that serves as both energy producer and compute infrastructure provider.

2. Commonwealth Fusion Systems — Leading the Race to Commercial Fusion

Commonwealth Fusion Systems (CFS), spun out of MIT's Plasma Science and Fusion Center, has raised $2.9 billion in total funding to develop commercially viable nuclear fusion power plants using high-temperature superconducting (HTS) magnets. The Cambridge, Massachusetts-based company is building SPARC, a compact tokamak designed to demonstrate net energy gain from fusion — a milestone that would represent one of the most consequential scientific achievements in history. CFS's proprietary HTS magnet technology enables smaller, more cost-effective fusion reactors compared to traditional approaches. The company has attracted investment from prominent backers including Breakthrough Energy Ventures, Tiger Global, and Google. With its ARC commercial power plant design targeting the early 2030s for grid deployment, CFS is positioning itself to deliver abundant, clean baseload power at scale.

3. Helion Energy — Fusion Power for Microsoft and Beyond

Helion Energy has raised approximately $2.7 billion in total funding to develop its proprietary magneto-inertial fusion technology, making it one of the best-funded fusion companies globally. Based in Everett, Washington, Helion's approach differs fundamentally from traditional tokamak designs — the company's fusion engine directly converts fusion energy to electricity without steam turbines, potentially achieving higher efficiency and lower costs. Helion made global headlines when it signed a power purchase agreement with Microsoft to supply fusion-generated electricity by 2028 — the first commercial fusion power agreement in history. The company's seventh-generation prototype, Polaris, is designed to demonstrate net electricity production, a critical milestone on the path to commercialization. Helion's backers include Sam Altman (who led a $375 million round), Mithril Capital, and Capricorn Investment Group.

4. Fervo Energy — Reinventing Geothermal for the AI Era

Fervo Energy secured $1.5 billion in its Series E round in late 2025, validating the enormous potential of enhanced geothermal systems (EGS) as a source of 24/7 carbon-free baseload power. Unlike traditional geothermal that requires naturally occurring hot water reservoirs, Fervo's technology adapts horizontal drilling and hydraulic fracturing techniques from the oil and gas industry to create geothermal wells virtually anywhere. The Houston-based company is constructing the world's largest geothermal project — a 400-megawatt facility — and has secured power purchase agreements with Google to supply carbon-free energy to its data centers. Fervo's approach addresses a fundamental limitation of wind and solar — intermittency — by providing consistent, dispatchable clean energy around the clock. As AI data center demand surges, Fervo's ability to deliver reliable zero-carbon baseload power positions it as a critical infrastructure provider.

5. Form Energy — 100-Hour Iron-Air Batteries

Form Energy raised $405 million in its Series D round to develop iron-air battery systems capable of storing electricity for up to 100 hours — roughly 25 times longer than conventional lithium-ion batteries. Based in Somerville, Massachusetts, the company's technology uses one of the most abundant and inexpensive materials on Earth: iron. Form Energy's batteries work by reversibly rusting and de-rusting iron, a process that is inherently safe, non-toxic, and dramatically cheaper than lithium-based alternatives for long-duration applications. The company is building its first commercial-scale manufacturing facility in Weirton, West Virginia, targeting utility-scale deployments that enable grids to operate on 100% renewable energy even during extended periods without wind or sun. Form Energy has secured partnerships with major utilities including Great River Energy and Xcel Energy for pilot deployments.

6. Oklo — Advanced Fission Goes Public

Oklo, the Y Combinator-backed advanced fission company, became one of the first next-generation nuclear companies to go public, trading on the NYSE under the ticker OKLO. The Santa Clara-based company develops compact, fast-fission microreactors called Aurora powerhouses that can generate 15-50 megawatts of emission-free electricity using recycled nuclear fuel. Oklo's reactors are designed to operate autonomously for decades with minimal maintenance, making them ideal for remote locations, military installations, and industrial facilities. The company's approach to nuclear fuel recycling addresses both energy generation and nuclear waste reduction simultaneously. Backed by Sam Altman and other prominent Silicon Valley investors, Oklo represents the vanguard of the nuclear energy renaissance that is gaining momentum as policymakers and technologists recognize nuclear power's essential role in decarbonization.

7. Radiant Industries — Portable Nuclear Power

Radiant Industries has raised over $150 million to develop portable nuclear microreactors that can be transported in standard shipping containers and deployed anywhere in the world. Founded by former SpaceX engineers, the El Segundo, California-based company is designing its Kaleidos reactor to deliver 1+ megawatt of clean electricity — enough to power approximately 1,000 homes or a forward operating base. Radiant's reactor uses TRISO fuel particles, considered the safest nuclear fuel ever developed, with each particle encased in multiple layers of ceramic and carbon that prevent the release of radioactive material even under extreme conditions. The company's initial market targets include military applications, disaster relief, remote mining operations, and off-grid communities. Radiant's unique combination of SpaceX-style engineering culture and nuclear technology expertise has attracted significant attention from both defense and commercial investors.

8. Energy Vault — Gravity as a Battery

Energy Vault, the Swiss-American company publicly traded on the NYSE (NRGV), has commercialized a gravity-based energy storage system that uses massive composite blocks raised and lowered by electric motors to store and release energy. The company's EVx platform can deliver 100+ megawatt-hours of storage capacity with a round-trip efficiency of approximately 80%, offering a long-duration storage solution that doesn't degrade over time like chemical batteries. Energy Vault has expanded beyond its signature gravity storage technology to offer hybrid energy storage systems that integrate multiple technologies including batteries and hydrogen. The company has secured deployment contracts across multiple continents and has partnered with major energy companies including Enel and BHP. Energy Vault's approach to storage addresses the critical need for grid-scale energy storage that can last for decades without capacity degradation.

9. Proxima Fusion — Europe's Fusion Champion

Proxima Fusion, a Max Planck Institute spin-off based in Munich, raised €130 million in its Series A round — the largest Series A for a fusion company in European history. The company is developing stellarator fusion reactors, a design that offers inherent plasma stability advantages over the more common tokamak approach. Proxima's technology leverages decades of research from the Wendelstein 7-X stellarator, the world's most advanced stellarator experiment. The company's AI-driven design optimization enables it to iterate on reactor configurations at unprecedented speed, potentially accelerating the path to commercial fusion. As Europe's most prominent fusion startup, Proxima has attracted backing from leading European venture capital firms and positions the continent as a serious contender in the global fusion race alongside U.S. and Chinese competitors.

10. H2Pro — Reinventing Green Hydrogen Economics

H2Pro has raised over $75 million to commercialize its proprietary E-TAC (Electrochemical-Thermally Activated Chemical) water-splitting technology for green hydrogen production. Based in Caesarea, Israel, the company's approach eliminates the expensive membrane required in traditional electrolysis, reducing both capital costs and maintenance requirements while achieving higher efficiency. H2Pro claims its technology can produce green hydrogen at under $1 per kilogram — a threshold that would make hydrogen competitive with fossil fuels for industrial applications, transportation, and energy storage. The company has established partnerships with major industrial players and has received backing from Breakthrough Energy Ventures, Sumitomo Corporation, and Horizons Ventures. As hydrogen emerges as a critical component of the decarbonization strategy for hard-to-abate sectors like steel, cement, and shipping, H2Pro's technology could play a pivotal role in making the hydrogen economy commercially viable.

Industry Analysis: The Energy Startup Landscape

The concentration of capital in energy startups reflects a fundamental recalibration of how investors view the energy sector. Three macro trends are driving this shift. First, the AI compute boom is creating unprecedented electricity demand — data centers are projected to consume 8-10% of global electricity by 2030, up from approximately 2% today. Companies like Crusoe and Fervo are directly addressing this demand with dedicated clean energy infrastructure. Second, the nuclear renaissance is gaining institutional credibility, with fusion and advanced fission companies collectively raising billions as policymakers recognize that intermittent renewables alone cannot achieve decarbonization targets. Third, long-duration energy storage has emerged as the critical missing link for renewable grid integration, with companies like Form Energy and Energy Vault offering solutions that extend storage duration from hours to days or even weeks.

Energy Market Statistics — 2025-2030 Projections

Category	Metric	Projected Value	Source
Energy Storage	Global Market Size (2030)	$546 billion	Fortune Business Insights
Renewable Energy	Global Market Size (2030)	$1,977 billion	Fortune Business Insights
AI Data Centers	Electricity Consumption (2030)	8-10% of global supply	IEA
Green Hydrogen	Market Size (2030)	$72 billion	McKinsey
Nuclear Fusion	Private Investment to Date	$7.1 billion+	Fusion Industry Association

Why This Matters

The energy startups profiled in this analysis are not merely building better products — they are constructing the foundational infrastructure for the next century of human civilization. The convergence of AI demand, climate imperatives, and technological breakthroughs has created an investment environment where energy innovation is simultaneously one of the most capital-intensive and most consequential venture categories. For enterprise technology leaders, the implications are direct: the cost, reliability, and carbon intensity of electricity will increasingly determine the competitiveness of AI infrastructure, manufacturing operations, and corporate sustainability commitments.

Forward Outlook

Over the next 12-36 months, several critical milestones will determine which of these companies emerge as dominant players. Helion Energy's Polaris prototype must demonstrate net electricity production. CFS's SPARC tokamak must achieve net energy gain. Fervo's 400MW geothermal plant must prove scalability. Form Energy's iron-air batteries must perform at commercial scale. And Crusoe must demonstrate that AI-energy convergence can sustain profitability at scale. The outcomes of these milestones will reshape investment patterns, energy policy, and the competitive landscape for decades to come.

References

About the Author

Aisha Mohammed

Technology & Telecom Correspondent

Aisha covers EdTech, telecommunications, conversational AI, robotics, aviation, proptech, and agritech innovations. Experienced technology correspondent focused on emerging tech applications.

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Frequently Asked Questions

What makes Crusoe Energy the top-ranked energy startup in 2026?

Crusoe Energy achieved a $10 billion+ valuation after raising $1.375 billion in its Series E round in October 2025. The company uniquely bridges AI infrastructure and energy transition by building data centers powered by stranded, wasted, or renewable energy sources. Its power pipeline exceeds 45 gigawatts, and it is a key partner in OpenAI's Stargate project, with projected revenue approaching $1 billion.

How close are fusion energy startups to delivering commercial power?

Commonwealth Fusion Systems and Helion Energy, the two leading fusion startups with combined funding of $5.6 billion, have set critical near-term milestones. CFS is building its SPARC tokamak to demonstrate net energy gain, while Helion signed the first-ever commercial fusion power purchase agreement with Microsoft targeting delivery by 2028. Commercial grid-scale fusion power plants are projected for the early 2030s.

What is enhanced geothermal technology and why is Fervo Energy significant?

Enhanced geothermal systems (EGS) use horizontal drilling and hydraulic fracturing techniques adapted from the oil and gas industry to create geothermal wells virtually anywhere, not just in naturally occurring hot zones. Fervo Energy raised $1.5 billion and is building the world's largest 400MW geothermal project, providing 24/7 carbon-free baseload power to customers including Google's data centers.

How does Form Energy's iron-air battery differ from lithium-ion technology?

Form Energy's iron-air batteries can store electricity for up to 100 hours — roughly 25 times longer than conventional lithium-ion batteries. They work by reversibly rusting and de-rusting iron, using one of Earth's most abundant and inexpensive materials. This technology is inherently safe, non-toxic, and dramatically cheaper for long-duration applications, making 100% renewable grids feasible.

Which energy startups are best positioned to benefit from the AI compute boom?

Crusoe Energy and Fervo Energy are most directly positioned. Crusoe builds AI data centers powered by stranded energy, delivering 30-50% lower energy costs than traditional hyperscalers. Fervo provides 24/7 carbon-free geothermal baseload power to tech companies including Google. As AI data centers are projected to consume 8-10% of global electricity by 2030, both companies address the sector's most pressing need: reliable, low-cost clean power.