Clean Energy Fuels Corp. signed a 15-year agreement through its subsidiary, Dallas Clean Energy LLC, for the sale of renewable biomethane produced at the McCommas Bluff landfill in Dallas. 

Beginning in April, the biomethane will be sold at prices that increase in 2010 and 2011 and, then, remain fixed over the remainder of the agreement. The price for the "green" gas was not disclosed, but represents a significant premium to the prevailing price for conventional natural gas.

The agreement calls for the sale of up to 4,500 MMBtus per day of biomethane from April 2009 through September 2010 and between 5,000-6,000 MMBtus per day of biomethane through March 2024. The actual volumes sold will depend on the gas recovery rates from the landfill and successful expansion of the gas processing facilities.

Shell Energy North America will act as the purchaser and supply the biomethane to the end-user — a utility that will use it in power generation to help meet applicable Renewable Portfolio Standards. Atmos Energy Corp. will provide intrastate transportation services from the gas processing plant. 

The interstate "green" gas sale agreement is believed to be one of the largest such sales of biomethane completed in the U.S.