It made sense to cavemen: If you need fuel, start with the branches and twigs all around you.
Eons later, the Modesto Irrigation District is thinking along the same lines. A plant proposed for the Beard Industrial District would burn wood from the region's orchards to make electricity.
Proponents see this as an ideal source for the MID's power customers: It would create local jobs, unlike fossil fuels from distant places. It would cleanly consume wood that farmers have long torched in the open.
"We set out to produce a unique, environmentally friendly biomass plant for the people of Modesto," said Robert Ellery, a partner in the project, at an MID board workshop last month.
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The 33-megawatt plant, which would meet 8 percent of the district's power needs, would burn about 375,000 tons of chipped wood each year from Stanislaus, Merced and San Joaquin counties.
Most of it would be from nut and fruit orchards removed to make way for new plantings or development. The fuel could include pruned limbs from living trees and wood waste from construction sites.
Ellery, who owns a Hayward boiler company, is a partner in the project with Stephen Endsley of Modesto, a real estate investor and retired cardiologist.
"This biomass plant is right in the middle of our community," said Endsley, a former almond grower.
The partners plan to spend about $80 million to build the plant. They hope to cover 30 percent of that with a federal economic stimulus grant.
The plant is expected to employ 22 people. Fifteen to 20 others would work for contractors that collect and haul the fuel. The plant, which could be running by fall 2012, would be the first biomass operation in the MID's territory. The state has about 30 such plants, including one near Chinese Camp that mainly uses trees thinned from forests.
The MID board had tentatively planned to vote on the project today, but it has been postponed to at least Aug. 24 so district staff can respond to concerns about the plant's environmental impacts.
The Stanislaus Taxpayers Association has been the main critic, questioning the cost and the emissions. It takes issue with the proponents' claim that controls on nitrous oxides, a key component of smog, would be among the tightest ever achieved.
"It is a completely fictitious, unsupported rate of emissions," association treasurer Eric Reimer said at the workshop. "It has never been accomplished."
The plant aims to emit no more than 0.012 pounds of nitrous oxide for each million British thermal units of heat produced from the wood. Ellery said his company, Bay City Boiler & Engineering Co., has a patent pending on an emission-control system that would achieve this.
The pollution limit would be one-eighth of the 0.1-pound standard that can be achieved with today's best technology, said Dave Warner, director of permit services for the San Joaquin Valley Air Pollution Control District.
He said that if the plant cannot meet the 0.012-pound target, it still would have to stay within 0.065 pounds, less than the current technology.
It's worth a try to achieve the lower rate, Warner said, to see if it can be applied to future projects. His agency has approved a tentative permit for the MID plant.
The taxpayer group also worries about the ammonia that would be injected into the plant's exhaust to help break up the nitrous oxide. The group claims some of the ammonia would escape, spreading a strong odor and irritating people's lungs.
Warner said "small amounts of ammonia are inevitably released into the air," and his agency would require monitoring to assure that the gas does not cause problems.
Most open burning on farms has been phased out under a 2003 state law. That has prompted critics of the biomass plant to ask whether it would do much to improve the air.
Warner said burning continues at about 20 percent of the old level under exemptions to the law, including one for small parcels.
"Open burning of ag waste is so dirty and thoroughly uncontrolled," he said. "Burning it in a controlled environment results in significant reduction in emissions."
The proponents also see the plant helping to stem climate change, believed to be caused mainly by burning of carbon-based fuels.
Wood is among these fuels, they acknowledge, but they say the emissions would be canceled out by the carbon that the trees absorb from the air while growing.
Jerry Jackman of Modesto questioned this assertion at the board workshop.
"Consider that trees grow for decades and this plant will be burning 1,000 tons a day," he said.
The backers of the plant say it also would reduce emissions of methane, an especially potent climate changer that is produced when wood decays. In many orchards, wood chips from pruned limbs are left on the ground to improve the soil quality.
The plant would provide a new market to people who make a living at pulling out orchards. One of them is Jesse Angel, based near Delhi.
"A local plant would be great because all of your costs pretty much are in trucking," he said.
Enough fuel supply?
Dave Thomas, president of the taxpayers association, questioned whether the region has enough wood to supply this and other plants. He said biomass is an unreliable source that would cost MID ratepayers far more than power from natural gas, the main fuel.
The price of the power has not been disclosed, but it is at a level that works for both the MID and the builders, said Greg Salyer, manager of resource planning and development for the MID.
He said biomass is somewhere between the cost of wind, the cheapest renewable source, and solar, the most expensive. And the 20-year contract would cap increases at 2 percent a year, he said.
The wood burner would have the advantage of running at all hours, district officials said. They point out that wind turbines turn only when the breezes blow and solar panels produce only when it's sunny.
The project got support at the workshop from the Modesto Chamber of Commerce and the Stanislaus Economic Development and Workforce Alliance.
"The Chamber of Commerce likes the fact that it provides local jobs in our community and that it is a green project," Chief Executive Officer Joy Madison said.
Phil Reese, chairman of the California Biomass Industry Alliance, said the plant would be relatively cheap to operate because it would be new and reliable.
Reese cited another advantage of this energy source: "Biomass is labor-intensive, and these days, that's a good thing."
Bee staff writer John Holland can be reached at 578-2385 or email@example.com.