In this article, we will list the 5 Best Green Energy Penny Stocks to Invest In. Please visit 9 Best Green Energy Penny Stocks to Invest In if you would like to see the extended list and the methodology behind it.

5. Clean Energy Fuels Corp (NASDAQ:CLNE)

Stock Price: $2.24

Number of Hedge Fund Holders: 21

Upside Potential: 123.21%

Clean Energy Fuels Corp (NASDAQ:CLNE) is one of the best green energy penny stocks to invest in. On May 4, Clean Energy Fuels Corp (NASDAQ:CLNE) announced the opening of additional renewable gas stations to expand its network of fueling locations. The company said it opened six new gas stations at strategic spots in California, New Jersey, Oklahoma, Michigan, and Washington. It said the new stations are near distribution centers and located along major freight corridors.

Clean Energy Fuels’ renewable natural gas (RNG) is sold as an alternative fuel for commercial vehicles. The spike in diesel prices as a result of the Middle East crisis has made RNG more attractive to fleet operators.

Clean Energy Fuels’ executive Chad Lindholm commented that with the high and volatile diesel prices, the timing was perfect to expand the company’s RNG offering. Lindholm noted that Clean Energy Fuels’ RNG offers price-stable and low-cost fuel to help fleets reduce their carbon emissions affordably.

The new gas stations strengthen Clean Energy Fuels’ network that spans more than 600 fueling locations across North America. The company’s stations serve refuse, trucking, municipality, and operations fleets.

Clean Energy Fuels Corp (NASDAQ:CLNE) produces and sells renewable natural gas used to power commercial vehicles, including heavy-duty trucks and buses. Its RNG is methane-based and is derived from organic waste, including dairy farm wastes. Clean Energy Fuels sells its RNG through a network of fueling stations.

4. Fuel Tech Inc (NASDAQ:FTEK)

Stock Price: $1.39

Number of Hedge Fund Holders: 4

Upside Potential: 212.50%

Fuel Tech Inc (NASDAQ:FTEK) is one of the best green energy penny stocks to invest in. Fuel Tech Inc (NASDAQ:FTEK) stock is up around 60% over the past 12 months. The Street expects it to explode more than 200% from its current level.

In its Q1 2026 report, released on May 5, Fuel Tech Inc (NASDAQ:FTEK) said its consolidated revenue declined to $6.1 million from $6.4 million a year ago. That’s a drop of 5% YoY. Additionally, the company’s net loss increased to $1.4 million from $0.7 million a year ago.

Those were the results. But getting into the details, Fuel Tech’s high-margin air pollution control (APC) business continued to grow. The APC segment revenue increased 23% to $1.6 million, and segment gross margin expanded to 38.3%, compared with 32.6% a year ago.

Fuel Tech closed Q1 with a backlog of $6.9 million in its APC segment, and the backlog has expanded since. On April 28, the company announced winning multiple APC contracts worth $10 million. It secured these contracts with utility and industrial customers.

The largest of these contracts was secured from a Midwest municipal utility. It involves integrating Fuel Tech’s Selective Catalytic Reduction pollution control technology with the utility’s natural gas-fired turbines.

Fuel Tech Inc (NASDAQ:FTEK) provides technologies for air pollution control, water treatment, and process optimization. Its solutions help support grid reliability and resilience. Moreover, the company offers systems that support the production of green hydrogen, a source of clean energy.

3. Ocean Power Technologies Inc (NYSEAMERICAN:OPTT)

Stock Price: $0.36

Number of Hedge Fund Holders: N/A

Upside Potential: 318.41%

Ocean Power Technologies Inc (NYSEAMERICAN:OPTT) is one of the best green energy penny stocks to invest in. The Street expects the stock to climb more than 300% from its current level.

Ocean Power Technologies Inc (NYSEAMERICAN:OPTT) continues to see demand for its PowerBuoy platform as it also works to solve a major problem in its industry: offshore autonomy. On May 7, the company announced progress in its offshore charging and autonomous operations program.

It was able to successfully demonstrate a system that allows maritime drones to dock, recharge, and return to operations without manned support. With that, the system addressed a major limitation in offshore autonomy.

The company plans to integrate the autonomous docking and charging capability into its PowerBuoy platform. It said this would create offshore charging points capable of supporting extended, lower-cost operations at sea.

More customers are reaching Ocean Power Technologies for its PowerBuoy system, which provides power and communication solutions at sea. On April 13, Ocean Power Technologies announced the deployment of its first PowerBuoy system for the US Department of Homeland Security.

It deployed the system off the California coast to support maritime surveillance for the U.S. Coast Guard. Additional PowerBuoy systems are expected to be deployed under the DHS contract.

Ocean Power Technologies Inc (NYSEAMERICAN:OPTT) is a New Jersey-based renewable energy company serving the maritime sector. It converts ocean waves, wind, and solar energy into electric power for offshore applications. Through its PowerBuoy platform, the company provides power and communication solutions for offshore operations.

2. Gevo Inc (NASDAQ:GEVO)

Stock Price: $2.03

Number of Hedge Fund Holders: 10

Upside Potential: 326.83%

Gevo Inc (NASDAQ:GEVO) is one of the best green energy penny stocks to invest in. GEVO stock is up almost 80% over the past year. The Street sees it exploding more than 300% from its current level.

In its Q1 2026 report, Gevo Inc (NASDAQ:GEVO) said it generated $43 million in revenue, compared to $29 million a year ago. The company made a $22 million loss in the latest quarter, the same as a year ago. The management said the latest results included $11 million in losses tied to debt refinancing and simplification transactions.

Adjusted EBITDA came to $9 million. That compares with the negative adjusted EBITDA of $15 million in Q1 2025.

Looking ahead, Gevo targets around $30 million in adjusted EBITDA in 2026, up from $17 million in 2025. The company expects to get there through revenue growth, operational performance, and cost controls.

Gevo’s growth plans include the Alcohol-to-Jet project, also called the ATJ-30. This project is about converting alcohols, such as ethanol, into jet fuel. The company said it has received interest from various capital providers to finance the project. Its goal is to secure financing for the ATJ-30 project by the end of 2026.

Gevo Inc (NASDAQ:GEVO), based in Colorado, is a renewable chemicals and biofuels company. It is focused on producing sustainable, low-carbon fuels. These include renewable gasoline, renewable diesel, and sustainable aviation fuel.

1. Aemetis Inc (NASDAQ:AMTX)

Stock Price: $3.08

Number of Hedge Fund Holders: 8

Upside Potential: 656.17%

Aemetis Inc (NASDAQ:AMTX) is one of the best green energy penny stocks to invest in. Aemetis Inc (NASDAQ:AMTX) stock has more than doubled year-to-date, and Street forecasts show it could soar over 650% from here.

The company reported its Q1 2026 results on May 7. The report showed revenue increased 27% YoY to $54.6 million. The company generated a gross profit of $2.8 million, compared to a loss of $5.1 million in the same quarter of the prior year. Aemetis closed the quarter with $4.8 million in cash.

The quarter was supported by growth in the renewable natural gas (RNG) and biodiesel segments. Aemetis said its biodiesel sales increased to $10.5 million as it resumed shipments under new tender orders.

The company recorded $4 million in revenue tied to the Section 45Z tax credit program. This tax credit program is designed to boost domestic production of low-carbon transportation fuels. Aemetis said $1.4 million of the Section 45Z tax credit was earned through its renewable natural gas segment, while $2.6 million was earned through the ethanol production segment.

Looking ahead, Aemetis said it is pursuing a broad financing plan to address both near-term needs and fund continued growth across its platforms. Among the growth efforts is the expansion of the renewable natural gas production capacity. The company is also working toward the IPO of its Indian subsidiary, which produces biofuels.

California-based Aemetis Inc (NASDAQ:AMTX) produces renewable natural gas and biofuels. Its solutions help businesses lower energy costs and reduce emissions. It has a facility in California that converts dairy waste to renewable natural gas. It also produces ethanol at a California plant. In India, it has a biodiesel production facility, and the company is developing a sustainable aviation fuel plant in California.

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