Climate Tech Startups 2026: Grid Storage Outpaces Carbon Capture

Different lists, same short shortlist

This year's rankings of climate tech startups disagree on plenty, but read together they point one way. In 2026, the companies drawing the most attention and the most money are the ones selling firm power and energy storage to a grid strained by AI data centers. Carbon capture gets almost as much discussion, but its delivery record is still well behind the storage companies.

The lists themselves are built very differently. Visible.vc's 15 picks lean heavily toward industrial hardware: Antora Energy's carbon-block thermal batteries, Rondo Energy's brick heat batteries, Heirloom's limestone direct air capture, Quaise Energy's millimeter-wave geothermal drilling, and Twelve's CO2-to-jet-fuel electrolysis.2 Trellis organized its 15 around data centers, materials and climate adaptation. Its picks include Airloom Energy's modular wind for data centers, etalytics' cooling-optimization software, and Elementium Materials' drop-in battery electrolytes.1 StartUs Insights went another way entirely, filling its watchlist with ESG compliance and carbon-accounting software firms such as GreenT, Earthena and Redwoods.ai.3

The split matters. Software-heavy lists show what is cheap to start, and hardware-heavy lists show where capital is actually being spent. MIT Technology Review's fourth annual list, released October 6, falls firmly in the second camp. It names Energy Dome, WeLion New Energy and the flood-barrier maker WaveSave among its 10 honorees.34 Its editors said energy storage stood out because demand for electricity is rising, driven partly by AI data centers. That is why the list includes three storage companies: Energy Dome, Moment Energy and Form Energy.33

Grid-scale storage is where the momentum is

The strongest case for storage is that real projects are being built. Form Energy is on MIT Technology Review's list for the third time for its iron-air batteries. It is working on a 30-gigawatt-hour project to help power a Google data center, to come online in phases between 2028 and 2031.31 The company raised a $405 million Series F, taking its total past $1.2 billion.19 One startup database puts Form's funding much higher, at $2.3 billion, and cites a separate $750 million raise.29 That gap probably reflects how fast the company has been raising rather than a true conflict, but readers should treat any single total for Form as provisional.

Energy Dome takes a more mechanical approach. Its plants liquefy carbon dioxide to store energy and then turn it back into gas to drive a turbine. Because the design needs no particular geology, it is easier to scale than traditional compressed-air storage.37 The company switched on a 200 MWh commercial plant in Sardinia in 2025. It says the technology is roughly 10% to 15% cheaper than lithium-ion for eight-hour storage, and in June 2026 it signed a Google deal for a 200 MWh plant in Ireland due in 2028.37 The same profile also lays out the drawbacks. Energy Dome has only one operating commercial project, its roughly 70% round-trip efficiency trails lithium-ion's roughly 90%, and one version of its system burns natural gas.37 That kind of candor is rare in ranking pieces and worth noting.

Sodium-ion goes commercial in 2026

The clearest change in battery chemistry this year is sodium-ion's move from pilot projects to purchase orders, a shift most watchlists have not caught up with. In June, CATL launched its TENER Sodium storage system in Munich, which it calls field-validated. Each module holds more than 30 MWh, deliveries in China start in September, and shipments are expected to reach 1 GWh by year-end.25 The system matches the size and shape of existing LFP units, so developers can swap it in without redesigning projects or repeating certification.25 Industry coverage also reports a three-year, 60 GWh sodium-ion supply deal between CATL and HyperStrong.30

In the U.S., Peak Energy has become the main sodium-ion company to watch. General Motors partnered with the startup and invested in it through GM Ventures. GM will develop grid-specific sodium-ion cells at its Warren, Michigan lab, with prototypes due this year.28 TechCrunch reported that GM's cells will not enter trial production until 2028, and that no automaker outside China had announced plans to build sodium-ion cells before this.24 In the meantime, Peak announced a $71 million, 4 GWh factory near Sacramento.21 It also lists a 4.75 GWh contract with Jupiter Power and more than 6 GWh contracted through 2030.22 Alsym Energy is a second U.S. entrant: developer Juniper Energy plans to deploy 500 MWh of Alsym's non-flammable sodium systems in California.23

The main caveat is cost. Sodium is abundant, but early-2026 estimates put CATL's sodium cells at around $70 per kWh, compared with about $40–45 for Chinese LFP cells.26 For now, the case for sodium-ion is built on safety, longevity and cold-weather performance, not price. Peak's passive design, which drops active cooling and fire suppression, is aimed at exactly those advantages.24

EV batteries: big lab results, slow factories

On the vehicle side, WeLion shows both the promise and the limits of next-generation cells. The Beijing company reported a semi-solid-state cell reaching 824 Wh/kg in 2025 testing, more than three times a typical lithium-ion battery.36 Its commercial record is more modest. Only about 200 of its 360 Wh/kg packs for Nio were built because of high cost, and the company would not say how many charge cycles its record cell can survive.36 WeLion has 11 GWh of annual capacity, another 18 GWh under construction, and plans for an all-solid-state car battery in 2027.36 Our reading is that lab energy-density records like this are a long way from cars on the road. The more useful milestones are WeLion's electric cargo ships and drone batteries.

Battery-adjacent startups are also benefiting from the AI power boom. Redwood Materials runs a 12 MW/63 MWh microgrid built from second-life EV packs at a Crusoe data center in Nevada, and GM has about 10,000 used packs headed to Redwood.24

Carbon capture: lots of capital, little captured carbon

Carbon capture features on nearly every list, but the reporting on it is the most divided. On the hopeful side, Heirloom plans to bring a 17,000-ton Louisiana facility online in 2026 and phase in a 300,000-ton site through 2027.2 CarbonCure says it has passed 10 million truckloads of low-carbon concrete and about 750,000 metric tons of CO2 permanently stored in it.2 Twelve's Moses Lake plant is scheduled to start producing jet fuel from captured CO2 this year.2

The skeptical side has strong evidence too. Climeworks has raised more than $1 billion, yet its Mammoth plant reportedly captured just 105 tons in its first year against a 36,000-ton capacity.13 One analysis estimates $3.6 billion has gone into carbon removal startups since 2021. It also finds the sector depends heavily on the 45Q tax credit, worth $85 per ton for industrial capture and $180 per ton for direct air capture.11 A tracker of 76 deals since 2024 found that seven rounds above $50 million took 49.1% of all comparable capital.16 A separate ranking found that only 17 of 83 carbon capture startups raised money in the past year. It also noted that investors increasingly favor companies that turn CO2 into products they can sell.15

The figures themselves vary. Climeworks' total is given as over $1 billion in some reports and $957 million in another.1115 Heirloom's total ranges from "$200M+" to "$500M+" depending on the source.1311 The direction is consistent even if the numbers are not. Money is going to the companies whose CO2 ends up in concrete, fuel or beverages, because those revenues do not depend entirely on subsidies.

Clean firm power and the data-center buyer

Geothermal is this year's standout exit. Fervo Energy went public in 2026. MIT Technology Review puts the IPO at $2.2 billion, while another report gives $1.9 billion and a 35% first-day gain.314 Either way, Fervo plans a gigawatt of plants by 2030.31 Further out, Quaise has drilled 118 meters into granite with millimeter waves and is targeting commercial operation in Oregon by 2030.2 Venture activity this autumn points the same way. Recent rounds include Reverion's $175 million Series B in clean power and storage and Kairos Power's $70 million strategic raise for advanced nuclear.14

The reading

The common thread is buyers. Big Tech's data centers are now the anchor customers for storage and firm power, as the Google deals with Form, Energy Dome and Fervo show.3137 Carbon removal has no buyer of that size, which helps explain why it still relies on tax credits and voluntary offtake agreements. MIT Technology Review also notes that U.S. policy rollbacks have pushed most of its honorees outside the country, and that China is the center of energy-tech innovation.3331 For startups, the takeaway is simple: in 2026, the clearest way to grow is to build something a power-hungry data center will pay for.