Through a unique partnership with an electricity supplier, giant refuse hauler Waste Management has come up with a cost-effective way to convert trucks to cleaner natural gas fuel.

San Diego area utility PG&E Corp. announced Friday that it will underwrite the cost to convert 90% of Waste Management's fleet in San Diego County to cleaner-burning LNG (liquified natural gas) vehicles over the next 18 months.
In return, PG&E Corp. receives the emissions credits it must have to build a much-needed electric power generating station in the area. Residents in booming San Diego County have incurred huge rate increases in recent months due to the shortage of electric power generated.
The new 500-megawatt Otay Mesa Generating Project will also be powered by natural gas and will produce enough electricity to power 500,000 homes.
PG&E Corp. has agreed to pay Waste Management the difference in cost between replacing 120 of its existing trucks based in El Cajon, Calif., with updated diesel-fueled engines and replacing them with LNG-fueled trucks.
The conversion is expected to reduce nitrogen oxide emissions in the area by more than 35 tons a year. That's one third of the NOx offsets required for the new generating plant. The rest will come from the conversion of marine vessels and other stationary sources in the San Diego area.
The 120 new trucks will be supplied by Mack. They will be powered by 12-liter Mack E7G Eco-Tech spark-ignited engines. The engines use advanced control systems specifically for natural gas fuel.
The trucks will have two special LNG cryogenic tanks which keep the fuel at very low temperatures. Each vehicle will carry 150 gallons. Alan Walsh, district manager for Waste Management in San Diego, said the fleet's diesel trucks currently consume around 50 gallons a day. The LNG-powered units are expected to consume about twice that, hence the need for more fuel capacity.
A Mack spokesman said the LNG conversion adds around $40,000 to the cost of the vehicle.
PG&E Corp. is also helping pay for a new LNG fueling facility to be built at Waste Management's El Cajon terminal. The new facility is expected to cost $1.5 to $2 million and be completed in six months. Other fleets in the area operating LNG vehicles would be able to use the fueling facility also, Walsh said.