Phoenix-based Republic Services Inc. is expanding an existing agreement giving the refuse hauling company increased volumes of renewable natural gas (RNG).

Newport Beach, CA-based Clean Energy plans to increase volumes of its RNG Redeem brand by three times what Republic used for its natural gas vehicle (NGV) fleet last year. The expansion would enable Republic to reduce its fleet emissions by 110,000 metric tons of carbon dioxide equivalent over a three-year period, a spokesperson said.

According to Republic, RNG has the lowest carbon intensity of all commercially available transportation fuels, and the overall carbon reductions over the period would equal the the effect of planting 2.8 million trees or removing 23,200 cars from the road.

“As the operator of the eighth-largest vocational fleet in the country, we have a number of initiatives to reduce overall fuel usage, including our continued commitment to operating compressed natural gas (CNG)-powered trucks,” said Pete Keller, vice president of recycling and sustainability. “We work hard every day to decrease vehicle emissions across our fleet through intelligent routing, our One Fleet maintenance initiative, and the use of renewable fuels.”

Republic plans to deploy Redeem across its CNG fleet in 20 states. Derived from biogenic methane or biogas, or methane that is generated by the decomposition of organic waste in landfills or digesters, the methane gas is then processed, purified and sent into interstate natural gas pipelines and made commercially available to Clean Energy customers.

Republic is building what it calls “durable practices and programs” to improve its environmental and social impacts through decreased vehicle emissions, landfill technologies, use of renewable energy, community engagement and employee growth opportunities.

Nationwide, Republic operates a fleet of more than 2,500 CNG vehicles and 38 natural gas fueling stations. The CNG fleet is estimated to save roughly 18 million gallons of diesel fuel annually. Republic has set a sustainability goal to reduce by 2018 fleet greenhouse gas (GHG) emissions by 3%.

Separately, Clean Energy on Thursday previewed the “From Sea to Shining Sea” NGV Rally, which kicks off in Southern California on Monday with an 18-city cross-country route ending June 16 in Washington, DC. Clean Energy is sponsoring the event with NGVAmerica, the California NGV Coalition and Southern California Gas Co. Sponsors said the road trip for NGVs would call attention to the ability of NGVs to reduce GHG emissions.