Chevron Corp. is accelerating its push to convert cow manure into renewable natural gas as part of its effort to reduce its carbon footprint. 

The oil major and its joint venture partner Brightmark LLC, a waste solutions manager, will build another 10 facilities to produce dairy biomethane to fuel long-haul trucks, according to the companies. They’re already developing 28 plants in seven states, with the first set to begin production this year. 

The push comes as oil and gas producers face increasing pressure to show a roadmap to become more green. So-called renewable natural gas is produced from methane, the second-largest contributor to climate change. The technology for capturing methane from farms, landfills and other sites has been around for years, and is starting to gain traction as cities and businesses look for ways to curb emissions. Chevron and other oil companies say the fuel is a net positive in the battle against global warming, but critics argue it’s just a crutch to keep fossil fuels in the mix. 

“We believe this is a good solution for lower carbon transportation fuels,” Andy Walz, president of Chevron’s Americas fuels & lubricants, said by phone. “We think we can influence” trucking fleets to switch.

Chevron and Brightmark declined to discuss the cost of their Brightmark RNG Holdings joint venture. 

The average cost to build a renewable gas facility has been about $17 million in the past but that’s been increasing and many now $30 million, says Matt Tomich, president of industry group Energy Vision.