While startup investment has been climbing lately, not all industries are partaking in the gains.

Cleantech is one of the spaces that’s been mostly left out. Overall funding to the space is down this year, despite some pockets of bullishness in areas like fusion and battery recycling.

The broad trend: Cleantech- and sustainability-related startup investment has been on a downward trajectory for several years now. And so far, 2025 is on track to be another down year.

On the bright side, however, there’s been some pickup in recent months, boosted by big rounds for companies in energy storage, fusion and other cleantech subsectors.

The numbers: Investors put an estimated $20 billion into seed- through growth-stage funding to companies in cleantech, EV and sustainability-related categories so far this year.

That puts 2025 funding on track to come in well below last year’s levels, which were already at a multiyear low.

Still, quarter by quarter, the pattern looks more encouraging. Investment hit a low point in Q1 of this year and recovered some in the subsequent two quarters. The current quarter is also off to a strong start.

Noteworthy recent rounds

The largest cleantech-related round of the year closed this month. Base Power, a provider of residential battery backup systems and electricity plans, raised $1 billion in Series C funding. The Austin, Texas-based company says its systems allow energy providers to more efficiently harness renewable power.

The second-largest round was Commonwealth Fusion Systems’ $863 million Series B2 financing. The Devens, Massachusetts-based company says it is moving closer to being the first in the world to commercialize fusion power.

For a bigger-picture view, below we put together a list of 10 of the year’s largest cleantech- and sustainability-related financings.

The broad takeaway: Startups innovating for an era of rising power consumption

Not to over-generalize, but if there was one big takeaway from recent cleantech and sustainability startup funding, it would be that founders and investors recognize that these are times of ever-escalating energy demand. They’re planning accordingly, looking to tap new sources of power, fusion in particular, as well as better utilize and scale existing clean energy sources.

Related Crunchbase query and list:

• Cleantech, EV & Sustainability-Related Funding, 2025 YTD
• Large 2025 Financings For Cleantech, EV And Sustainability Startups

Illustration: Dom Guzman

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Mapping India’s cleantech sector: Key players, top investors, and funding insights in one report.