Biogas may power county cars

Jul 20 - The Arizona Daily Star

July 20--For years Pima County officials have struggled with what to do about smelly sewer gas.

Their newest potential solution -- put it in their cars and drive it to work.

That's right. County planners are looking at the possibility of turning gas from a wastewater treatment plant into fuel that can power county vehicles.

The biogas produced at the Ina Road facility is used to power part of the facility, but the on-site generation equipment is old and costly.

The county is using more economical commercial electric power now and plans to close the generation station in 8 to 14 months as part of a new and improved Ina facility, said Jackson Jenkins, director of the Pima County Regional Wastewater Reclamation Department.

Plus, plans to consolidate solid waste processing at the Ina facility mean there'll be a lot more gas.

What to do with the gas?

The county wants to upgrade the gas to pipeline quality, probably through a contract with a private partner, and then sell it or use it to power compressed natural gas (CNG) vehicles.

A consultant has been studying the issue for the county.

The private partnership is attractive because it would cost about $9 million to construct a gas upgrading system and about $500,000 each year to operate and maintain the system, according to the consultant's report.

If a private partner takes on those costs, there would be no affect on sewer customers, and the county would earn some income from the sale of gas, Jenkins said.

The county doesn't have a lot of CNG vehicles right now, but it could replace old vehicles with CNG ones over time, the report says.

Natural-gas prices are currently very low, which makes converting the fleet attractive, but it could cost more to upgrade biogas than to buy natural gas in the short term, the report says.

"On the other hand, the positive public relations value" of having a biogas-fueled fleet "may be substantial," according to the report.

If the county goes that route, it would also need to buy fuel stations and pipelines to move the gas to the fuel stations or partner with a private company.

The Wastewater Department wants to make a decision in the next few months, Jenkins said. The final decision will be made by the Board of Supervisors.

Contact reporter Becky Pallack at bpallack@azstarnet.com or 573-4346.

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