French oil major Total SA on Thursday agreed to accelerate the push to convert more heavy-duty trucking fleets to run on natural gas in partnership with Clean Energy Fuels Corp., a pioneer in advancing the North American natural gas vehicle (NGV) fueling network.

Total agreed to invest $83.4 million, or take up to 50.8 million shares of Clean Energy, to become the largest stockholder with 25% ownership. The deal is subject to the approval of Clean Energy stockholders at their upcoming meeting scheduled for June 8.

With the new infusion of equity, Clean Energy plans to launch an automotive leasing program designed to put thousands of NGV heavy-duty trucks on the road. The program is aimed at making it easier for fleet operators to switch to NGV trucks with the Westport Cummins near-zero emission engines operating on renewable natural gas (RNG), marketed under its Redeem brand.

Total intends to provide up to $100 million of credit for the leasing program, which is set to launch in 3Q2018. Clean Energy said the cost to convert heavy-duty trucks to run on natural gas can be high, or as much as $40,000/truck. Along with the leasing help, fleet operators would be given 50 cent/gallon discounts on RNG fuel.

Total would also appoint members to the Clean Energy board. If the deal is approved, some Total executives also would be transfer work with Clean Energy, which is headquartered in Newport Beach, CA.

In the past 20 years, “we have never had the major oil companies involved” in the NGV business, said Clean Energy CEO Andrew Littlefair, who called Total’s announcement “a watershed moment.

Launching the financing program should expedite the adoption of natural gas “as the most environmentally friendly fuel for the trucking industry, Littlefair said.

“Being a European-based company, Total is all too aware of the opportunity to transition to cleaner alternative fuels,” he added.

Indeed, Total has been transitioning over the past several years to position itself to become more carbon neutral, relying less on oil and more on natural gas and alternative fuels. It already is one of the largest producers in the United States, with oil and gas holdings in the onshore and Gulf of Mexico, and substantial — and growing — holdings in liquefied natural gas (LNG).

Total, among other things, has a 23% stake in Tellurian Inc., which has a vast array of natural gas pipeline projects and the Driftwood LNG project, on the drawing board. Last fall, with an agreement to buy Engie, Total prepared to gain that company’s 16.6% stake in the Sempra Energy-led Cameron LNG export facility in Louisiana, a 15 million metric tons/year (mmty) project now scheduled to start up in 2019.

With Engie, one of the world’s largest LNG operators, Total’s overall LNG volumes by 2020 would total about 40 mmty, making it the second largest global player among the majors” behind Royal Dutch Shell plc, with a worldwide market share estimated at 10%.

Citing a key role for natural gas in Total’s low-carbon strategy, CEO Patrick Pouyanné, said regulators and customers worldwide are “demanding cleaner transportation alternatives.” In the heavy-duty truck market, “natural gas can become the fuel of choice,” he said.

“Total has vast experience with natural gas, with operations on five continents, making Total one of the world’s largest leaders all along the natural gas value chain, including with liquefied natural gas positions in the United States,” a spokesperson said.

In 2017, Clean Energy Fuels recorded a 32% year/year increase in sales of Redeem, selling 79 million gallons, compared with 60 million gallons a year earlier. Last year’s volume represented more than half of the overall U.S. RNG production, according to the U.S. Environmental Protection Agency.

Also on Thursday, Clean Energy reported 1Q2018 net income of $12.2 million (eight cents/share), compared with $61.1 million (40 cents) in 1Q2017.