Montauk Renewables is one of the largest U.S. producers of renewable natural gas (RNG), with over 30 years in the business. Montauk captures biogas — primarily methane — from landfills and agricultural waste as it decomposes, then purifies it into pipeline-quality RNG that is injected into the interstate natural gas pipeline and sold predominantly as a transportation fuel for CNG/LNG vehicles. Montauk currently operates 11 RNG projects and 2 Renewable Electricity projects across seven states. Montauk makes money two ways: from the commodity value of RNG itself (priced off Henry Hub), and from environmental credits generated because the gas comes from non-fossil organic sources. The more important revenue driver is D3 RINs — federal compliance credits generated under the Renewable Fuel Standard that refiners must purchase — supplemented by California LCFS credits for its dairy manure project and RECs from its electricity segment. Montauk self-markets a large portion of its RINs directly to refiners, including Valero and ExxonMobil. Its biogas supply is heavily concentrated with Waste Management and Republic Services, which together host eight of Montauk's 13 projects. D3 RIN prices are volatile and directly drive profitability. Montauk's smaller Renewable Electricity segment sells power and RECs under long-term fixed-price contracts, providing more stable but modest revenue. Montauk is expanding into agricultural feedstocks, biogenic CO2 capture, and green methanol to diversify beyond its landfill RNG core.