Clean Energy Fuels Corp., the leading provider of natural gas fuel for transportation in North America, announced that Estes Express Lines will add to its fleet 50 new trucks fueled with Redeem renewable natural gas (RNG), bringing its total to 71.

Estes, the nation’s largest privately-owned freight transportation carrier, is acquiring the Class 8 natural gas trucks equipped with the Cummins Westport ultra-clean ISX12N engine for its California fleet, and is expected to use an approximate 2.8 million gallons of RNG over the seven-year contract.

Clean Energy’s Redeem was the first commercially available RNG vehicle fuel, derived from capturing the biogenic methane produced by the decomposition of organic waste from dairies, landfills, and wastewater treatment plants. Redeem reduces climate-harming greenhouse gas emissions by at least 70%, and even up to 300% depending on the source of the RNG.

Estes purchased the trucks through Clean Energy’s Zero Now program, which brings the price of a natural gas truck at parity with a diesel truck, while offering a guaranteed fuel discount for the duration of the agreement. For Estes, this represents a geographical expansion of its current 21 ultra clean truck fleet currently operating out of Texas, and also fueled by Redeem.

A fourth-generation company, Estes was established in 1931 and currently ranks among the nation’s top 10 national less-than-truckload carriers with 19,000 employees and a fleet of 7,000 tractors and 30,000 trailers.