You turn the switch and the light comes on.

But where the power we use in Central Oregon comes from is a hard question to answer. Statewide data and information about the biggest power provider here give clues as to what sources are powering Central Oregon: mostly power-producing dams and coal-burning power plants.

The biggest power provider in the region is PacifiCorp, which operates Pacific Power in the Northwest. The privately held company has 72,744 customers in Crook, Deschutes and Jefferson counties and supplies power to most people living in Bend. PacifiCorp has an array of power sources, from coal-burning plants in Wyoming to wind farms in Eastern Oregon. The sources all put electricity into the company’s system, which powers homes in Oregon, California, Idaho, Utah, Washington and Wyoming. The system doesn’t have a way to determine where the power ends up, said Bob Gravely, Pacific Power spokesman.

“It is all kind of like if you had 70 hoses filling a bathtub and you took out a cup and asked, ‘What hose did this water come from?’” he said.

The Oregon Department of Energy annually collects data on the mix of sources used by utilities supplying power around the state, showing what spigots are feeding the different hoses.

Oregon’s source of choice is hydropower, water turning turbines, according to the Department of Energy data collected from 2010 to 2012. Of the power supplied to consumers in the state, 45 percent is from hydro. Second is coal, making up 33percent of the power supplied in the state, even though there is only one coal-burning plant in Oregon. Mostly owned by Portland General Electric , the plant is in Boardman along the Columbia River Gorge and is set to be closed or switch from coal to biomass — wood or other plant-based fuel — by 2020, said Steve Corson, spokesman for PGE. The rest of Oregon’s coal power comes from elsewhere around the West.

After hydro and coal, there is a wide mix of other power sources in Oregon, including natural gas, wind and nuclear. Natural gas accounts for 12 percent, wind 5percent and nuclear 3percent. The remainder comes from a combination of biomass, geothermal and other sources.

The Department of Energy also has a power source breakdown for PacifiCorp, which provided nearly 30 percent of the power in the state, according to data from 2010. The company produces 90 percent of its own power and buys 10 percent on the open power market. Of the power PacifiCorp produces for itself, 67 percent comes from coal, 16 percent from natural gas, 8.5 percent from hydro, 6 percent from wind and the rest from a mix of biomass, geothermal and other sources.

The state and PacifiCorp’s power portfolio is changing, with deadlines approaching to hit targets for more renewable power, and Gov. John Kitzhaber is specifically pushing for more wind power.

“We made quite a bit of investment in wind in the last six years,” said Gravely, the PacifiCorp spokesman.

He said the company is in good shape to meet the state’s renewable requirements. The goal for companies the size of PacifiCorp is to have 25 percent of their power coming from renewable power sources by 2025. Renewable sources include wind and solar, and some forms of hydro.

The 2007 Legislature created the renewable standard that set the targets for utilities in Oregon. Smaller utilities, such as Central Electric Cooperative, are required to have at least 5 percent of their power supply coming from renewable sources by 2025.

Central Electric is the second-largest power provider in Central Oregon. Unlike PacifiCorp, — which is owned by a subsidiary of Berkshire Hathaway, Warren Buffet’s holding company — Central Electric, Midstate Electric and Wasco Electric, which also provide power in Central Oregon, are all cooperatives. They are owned by their members.

Not having a power source system as PacifiCorp does, Central Electric and the other electric cooperatives rely on the Bonneville Power Administration for their power.

“Our power all comes from the BPA,” said Jeff Beaman, spokesman for Central Electric.

A federal nonprofit agency, the Bonneville Power Administration draws most of its electricity from power-producing dams along the Columbia River, said Doug Johnson, BPA spokesman. The agency then sells the power to the cooperatives through 20-year contracts.

About 82 percent of the power from the BPA comes from hydro and 12 percent comes from a nuclear power plant in Washington. The remaining 6 percent is power bought on the open market from a variety of sources, including coal, natural gas and wind.

“It’s a vast mix of things,” Johnson said.

Not all hydro projects are considered renewable, said Margi Hoffmann, energy policy adviser for Gov. Kitzhaber. Earning that designation depends on whether the projects have been built or improved to be more efficient since 1995 .

Beaman said Central Electric is on track to meet the renewable power source targets set by state lawmakers.

As the state’s energy portfolio changes with the push for more renewable power over the next decade, there will probably be a move from coal to natural gas, Hoffmann said.

Although natural gas is not considered a renewable energy, it does put out less pollution than coal and is currently an inexpensive fuel. It isn’t free of controversy, however, with environmental groups raising concerns about fracking, or the hydraulic fracturing of rock to release underground pockets of natural gas. Still, power companies are picking natural gas over coal.

“Right now, today, it seems more prudent and less risky for utilities to invest in natural gas rather than new coal generation,” Hoffman said.

— Reporter: 541-617-7812, ddarling@bendbulletin.com