Clean Energy Fuels Corp. (CLNE) announced that Estes Express Lines is expanding its “Redeem” renewable natural gas (RNG) fueled fleet to a total of 71 by adding 50 new trucks.

Clean Energy is leading provider of natural gas fuel for transportation in North America while Estes is the nation’s largest privately-owned freight transportation carrier. Estes is acquiring the Class 8 natural gas trucks with the Cummins Westport ultra-clean ISX12N engine fitted in for its California fleet. Under the seven-year contract, the transportation company is likely to be using an approximate 2.8 million gallons of RNG.

With Redeem, Clean Energy made the first RNG vehicle fuel available commercially in the market. The natural gas fuel company derives the RNG from capturing the biogenic methane produced during the natural process of decomposition of organic wastes. Those include wastewater treatment plants wastes, landfills and dairies. The greenhouse gas emissions that are harmful to the environment reduce at least 70% with the use of Redeem. That percentage reduction could climb as high as 300% depending on the source from where RNG has been derived.

The truck being added by Estes have been purchased through Zero Now program of Clean Energy. The program makes the cost of leasing or purchasing a new natural gas heavy-duty truck at parity with a diesel engine truck or sometime even lower than that. The vehicles so acquired through Zero Now will also be able to purchase Redeem fuel at discounted prices.

Estes also purchase the trucks through Zero Now in a seven-year contract with guaranteed fuel discount for the duration of agreement. Estes is currently running ultra clean truck fleet of 21 trucks included in it. The new purchase will expand the Estes fleet’s geographical expansion which has been currently operating out of Texas. The current fleet of Estes has also been using Redeem for their RNG requirements.