Climate tech startups are capital intensive, timelines are long, and the technology is often considered “first of its kind.” What’s more, a key value proposition is addressing pollution — an externality that is, at best, poorly priced by the market. Those aren’t the qualities stock pickers tend to favor.

And yet, public markets appear to be warming to climate tech startups — or at least some of them.

This week, nuclear startup X-energy went public, raising $1 billion in an upsized share offering that appears to have delivered a windfall for its investors, including Amazon. Retail investors apparently can’t get enough, with the stock popping 25% in its first hour of trading. Also this week, geothermal startup Fervo said it filed for an initial public offering. The size of the Fervo IPO has yet to be disclosed, but private investors have valued the company at around $3 billion, according to PitchBook.

The move to go public aligns with what investors told TechCrunch at the end of last year. After years of tepid attitudes toward climate tech companies, they expected public markets to start welcoming energy-related startups. Nearly every investor that weighed in on the question said the startups with the best chances of going public specialize in either nuclear fission or enhanced geothermal. Fervo, specifically, was mentioned several times.

Thank data centers for that. The AI craze has taken a trend of rising demand for electricity and made it sexy and salable. Companies that were already betting on the upswing lucked into a trending narrative that coincided with their technological maturity. Fortune certainly favors the prepared. 

The IPOs are also certain to please investors, letting them return capital to their LPs. The recent dearth of IPOs has kept a chunk of climate tech funding locked up, at a time when many funds would like to start cashing out.

But it’s not just about cashing out.

Fervo and X-energy have followed the traditional route to public markets, suggesting there is confidence that a broad base of investors wants to participate. If it were just about freeing up investor capital, the startups could have followed the SPAC route. (Several have.) But these two companies took the longer path.

Yet for all that success, a wide swathe of climate tech will probably be left out of the IPO wave.

Companies that aren’t entangled in energy markets will have to find other ways to press on — and without access to the deep pockets the public market provides. The divergence suggests the climate tech world is starting to go K-shaped, a trend which Mark Cupta, managing director at Prelude Ventures, suggested when I spoke to him a little over a week ago.

Companies stuck on the poorer side of the IPO window still have private investors to lean on. But there, too, a K-shaped trajectory is starting to appear.

Venture capital and growth funds raised about $6.5 billion last year, according to Sightline Climate. That’s the same as in 2021, but because there are more funds today, each fund is now smaller. For founders, that could be bad news since funds have less to draw on. On the upside, more competition could drive better fundraising results.

At the same time, the big funds keep getting bigger. Infrastructure dominated climate tech fundraising last year, with 42 funds raising 75% of all dollars in the sector, according to Sightline Climate. That success will spill over into the startup side if it’s a company with a mature technology that is ready to build big. 

Sightline said that many new infrastructure funds are specializing in renewables, grid technologies, and energy storage. In other words, the K-shape isn’t going away anytime soon.