The Turlock Irrigation District could soon build a new, green energy plant, at a cost of more than $20 million.

The district is expected to issue a request for proposals, asking firms to pitch new renewable generation facilities.

That request for proposals isn’t necessarily a guarantee that TID will purchase additional generation at this exact time. District officials said the move is, in large part, intended to gauge the cost of such facilities.

But the district will need to acquire additional green energy in the near future to meet state mandates.

“We have an obligation by 2020 to meet 33 percent of our retail load with renewables,” explained Brian LaFollette, TID Assistant General Manager of Power Supply

TID staff previously thought they would be able to “bank” renewable energy created by the district’s Tuolumne Wind Project, a 136.6 megawatt facility in Klickitat County, Washington, to delay purchasing a new, green power plant. But a change in state policy means TID may need additional generation as soon as early 2019.

That generation could come in the form of more wind power, geothermal energy, biomass generators, fuel cells, or – most likely – solar power. The district could either own the new generation facility, or effectively lease it in a long term agreement.

Each technology has its own pros and cons, LaFollette noted, and will be judged on its own merits.

“The leading candidate, right now, is solar,” LaFollette said.

To meet the district’s needs, it could be looking at a 650-acre solar plant generating 185,000 megawatt-hours per year. It could cost as much as $21 million to construct, though costs are expected to be lower.

Additional costs would likely be incurred to construct or purchase transmission, integrating the power into the District’s system, and on some sort of battery technology (like the EnerVault battery outside of Turlock) to stabilize the flow of power coming out of the solar panels.

“We think now is a very good time to go out and check prices,” LaFollette said.