Petaluma city leaders seek tighter regulations on where commercial renewable-energy projects should be allowed on the county's ranches and farmland.

Sonoma County planners are considering zoning changes that, as proposed, would open 180,000 acres of pasture — mostly in the south county surrounding Petaluma — to large-scale solar and other renewable-energy generating installations.

A proposed 23-acre solar installation on 130 acres of grazing land near Frates and Adobe roads on the southeastern outskirts of Petaluma is prohibited under existing zoning. It would be allowed under the new rules.

The 4-megawatt project, enough to power about 750 homes, calls for 6,340 panels on 22.6 acres across from a PG&E substation and below high-voltage transmission lines. It is proposed by Coldwell Solar, a Placer County-based firm.

The new zoning proposal, under discussion by the county for two years, is scheduled to return to the Board of Supervisors on Aug. 6. The issue is separate from the Sonoma Clean Power agency concept.

The council unanimously agreed to send a letter outlining its concerns to the Board of Supervisors before Aug. 6.

At Monday night's meeting, City Councilwoman Teresa Barrett urged the county to tighten up its proposed regulations in several ways.

She said the county needs to respect urban separators, greenbelts and scenic gateways into its communities.

"The cities each voted to contain themselves to not have urban sprawl," she said. "Now you have the county putting sprawl in … and defeating the purpose of open space and urban growth boundaries."

She argued that the new regulations are backward – that they place the burden on the public to oppose a project instead of the landowner to prove why an intensified use of a property is beneficial.

In the debate, which is happening throughout the state as renewable energy possibilities grow, agricultural interests, environmental groups and conservationists are weighing the complicated choices between green energy development and landscape protection.

Most council members said they supported renewable energy projects, but that they must be balanced in context with Petaluma's agricultural identity — both past and future. The city is encouraging food and beverage producers to do business in town, which attracts food-related tourism.

Retaining greenbelts is "what keeps this area from turning into San Jose," said Mayor David Glass. "To just decimate the scenic corridor, I think that's really a violation of what the taxpayers have paid for with their open space purchases."

You can reach Staff Writer Lori A. Carter at 762-7297 or