Wind mills - as well as a solar farm and a methane gas powered generation plant - are being studied as viable ways to make Manteca's wastewater treatment plant energy independent of PG&E.

Manteca Public Works Director Mike Houghton confirmed Friday the city is aggressively exploring the three renewable energy resources as a way to chip away at or wipe out one of the biggest costs of running the waste water treatment plant - electricity.

Public works staff is working closely with the new consulting firm that was brought in to maximize the efficiency of the treatment plant that is the final stages of its expansion. The firm has come up with a plan that would greatly increase the volume it can handle under existing state rules which would reduce some of the need for future expansion and spread the cost of operating and maintenance the wastewater treatment plant over ultimately more users which generally lowers the size of the increase of future rate adjustments.

"Going solar would be a little tricky because of the payback involved," Houghton said after attending the dedication Friday of the South San Joaquin Irrigation District's $7.9 million solar energy farm on Dodds Road.

The SSJID solar farm is designed to provide almost all of the power needed to run the adjacent South County Surface Water Treatment Plant.

SSJID was able to make that project work effectively by selling renewable energy credits on the open market. Federal law allows major corporations and such to avoid stiff penalties for carbon-based pollution by investing in systems that others use that is green and renewable sources of energy. That way a heavy manufacturing plant on the East Coast, for example, that uses huge amounts of electricity and is in an area where solar isn't effective can meet the requirement by buying credits from renewable energy operations.

Houghton said SSJID has agreed to lend its expertise to help the city chart its course through the complicated and confusing renewable energy world.

For now, Houghton said the moist viable alternatives to start chipping away at the wastewater treatment power costs are the co-generation plant ran with methane gas that is generated by the treatment process and wind power.

"Even on cold days there is wind coming through Manteca," Houghton said.

Power costs figure heavily into a rate study that is going before the Manteca City Council tonight that calls taking the monthly residential rate up from $33.06 to $51.25 by 2013. That reflects a rate increase over the five years in excess of 50 percent.

The rate study is keeping with municipal policy to review enterprise funds every five years to make sure that they are being adequately funded to cover maintenance and operating costs as well as any replacement needs to avoid the system from going into disrepair, violating state and federal water act laws, and making sure they are self-supporting through payments from those who use the system.

A public hearing could be set for Oct. 6 to consider adopting the new rates. If that happens, they could go into effect starting on Jan. 1, 2009 with the initial step of a five-tier rate hike.

The study reviewed the current financial status of the fund projected operating and capital costs for the next five years.

The increases are being attributed to skyrocketing energy costs - the plant uses $1.1million in electricity in a given year - as well as other needs such as:

-  build the operating reserve up to the equivalent of four months.

-  creating a depreciation sinking fund to replace several thousand feet of aging large pipeline that is nearing the end of its useful life.

-  meeting more stringent state standards that are now in place for the collection and treatment of wastewater.

The council meets at 7 p.m. at 1001 W. Center St.