Cenergy Solutions, a developer of adsorbent natural gas storage systems, reports that it has delivered its first ANG vehicle to be used in a commercial fleet.

The fleet customer sent the truck to Cenergy for modification, said Gary Fanger, Cenergy’s chief operating officer, and now it’s been returned. The 2001 Dodge Ram B2500 van, with a 5.2-liter V-8 engine, is used by technicians who service power generation equipment. It was originally set up by Chrysler to use compressed natural gas.

Cenergy technicians added an ANG tank, then tested the truck to gauge performance and gas flow to the engine.

“We have been getting great results driving it in a variety of conditions, including steep grades in the mountains” near Cenergy’s tech center in Fremont, Calif., Fanger said. “You couldn’t tell the difference” in performance whether gas was taken from the ANG tank or stock CNG tanks.

“Some questioned whether the flow rate for ANG would be sufficient, and it seemed to be better,” Fanger said. “We think gas is de-adsorbing in the tank and flows better” than when it’s released under higher pressure from the stock tanks.

Cenergy’s adsorbent system uses carbon blocks or powder inside a tank, according to Fanger. When gas is pumped in, high amounts of it cling to the carbon instead of having to be crammed into the tank under high pressure. An adsorbent tank can hold six times more natural gas at 250 psi than a conventional tank, and 20% more in a tank pumped to 3,600 psi, the usual fill-up pressure for CNG.

ANG tanks can extend a vehicle’s range and lower the cost of gas because it needn’t be pumped to high pressures, Fanger said. Technicians are now retrofitting existing DOT compliant natural gas cylinders with their proprietary system. This equipment makes it possible to use low pressure (350- to 500-psi) tanks that are lighter and can be conformed to fit in various areas of empty space in a vehicle.

As work continues, a concrete ready-mix company in the Midwest that has committed to fueling its trucks with natural gas is interested in using adsorption tanks, which would be the first application in heavy trucks.

Cenergy meanwhile is working with a California biomethane-generation plant to boost storage capacity in existing tanks with ANG technology. The plant has been in operation for two years and will soon exceed storage capacity for natural gas in its low-pressure tanks.

Cenergy's ANG system is getting considerable interest from overseas because it has uses in stationary as well as vehicle fuel storage, he said.

ANG technology can be applied to virtually any type of natural gas storage system, including CNG vehicles, fueling stations, transport trucks and stationary natural gas storage. In its development work, Cenergy is collaborating with EnerG2, a global energy storage supplier.