3 Best Clean Energy Stocks to Buy Now

In 2023, the worldwide clean energy market was estimated to be about $0.7 trillion, according to a report from Allied Market Research. That same market is expected to grow at a compound annual growth rate (CAGR) of 9% to reach about $1.8 trillion by 2033.

Even if this growth comes to pass -- and it is only a projection, after all -- not every clean energy stock will be a long-term winner. Even those that remain won't see gains evenly distributed across the sector.

For growth-oriented investors, then, the key is to identify companies developing scalable energy solutions. With that in mind, here are three companies that are doing just that.

Image source: QuantumScape.

1. Oklo

Oklo (NYSE: OKLO) is developing compact nuclear reactors that can deliver up to 75 megawatts of clean power.

Its Aurora powerhouse will run on both specialized fuel and recycled nuclear waste, which will make it more efficient than traditional reactors and easier to deploy.

Because of their compactness, Oklo's reactors can be a feasible energy solution for off-grid and remote areas, like AI data centers and mining sites.

Oklo is pre-revenue, but has about $530 million in cash and equivalents. With an annual burn rate that's averaged about $53 million over the last 12 months, that gives it a few years to stay afloat.

With early backing from OpenAI's Sam Altman and a more recent push from the White House, Oklo's market value has exploded in 2025. It's a nuclear stock worth watching, especially if it gets regulatory approval to operate its Aurora at a commercial scale.

2. Bloom Energy

Bloom Energy (NYSE: BE) is a fascinating energy company. In a nutshell, it's designing solid oxide fuel cells that can convert natural gas, biogas, and hydrogen into clean electricity without combustion.

Bloom's fuel cells can offer reliable, 24/7 power with lower emissions than the conventional grid. As such, its target customers are those who demand highly reliable and preferably on-site power, such as data centers, manufacturing plants, hospitals, and utilities, among others.

Over the years, Bloom has built up an impressive list of blue chip customers. Fortune 100 companies like FedEx, Walmart, The Home Depot, and AT&T, among others, have all installed Bloom Energy Servers at their sites. Meanwhile, its data center clientele list, which includes big names like Oracle and Equinix, has been steadily growing.

3. QuantumScape

QuantumScape (NYSE: QS) isn't making novel energy solutions like Oklo and Bloom, but it has its hand in one of its most important technologies -- the battery.

In a nutshell, QuantumScape's big idea is to make a solid-state battery, which can charge faster and will last longer than a typical lithium-ion battery.

The simplicity of QuantumScape's battery, which doesn't require an anode, makes it cheaper to manufacture. This, in turn, could eventually reduce the cost of electric vehicles (EVs).

While the technology has legs, it hasn't been proven at a commercial scale yet. Indeed, QuantumScape isn't generating revenue right now, and it could be several years before it's close to turning a profit.

Like other clean energy startups on this list, expect volatility in the near term. For conservative investors, a clean energy exchange-traded fund (ETF) may be a better fit.

Steven Porrello has positions in Oklo. The Motley Fool has positions in and recommends Equinix, Home Depot, Oracle, and Walmart. The Motley Fool recommends FedEx. The Motley Fool has a disclosure policy.