For five hours early Wednesday the Pacific Northwest was running green, almost all of its electricity coming from hydroelectric dams in a river system flush with spring runoff.
That's a tiny carbon footprint. But it could also be a blow to the region's burgeoning wind industry, and could kill endangered fish in their spring migration.
The Bonneville Power Administration said Wednesday it followed through on a plan announced last week to shut down most of the region's power generation except that from government dams now running at full capacity.
The shutdown started at midnight and ended at 5 a.m. _ while most in the region slept and electricity demand was low.
"Push came to shove," spokesman Michael Milstein said. "We didn't want to do this, and we will only to the extent that we have to."
The shutdown could be repeated overnight Thursday, he said. And depending on how quickly the water flows to the Pacific Ocean, the region is expected to be using hydropower heavily for at least a few weeks.
The volume of runoff is the greatest in more than a decade. The agency says that strains the ability of river managers to balance numerous interests, such as protecting endangered salmon and steelhead, and preventing floods. Among electricity producers, the spring rise is an expected part of operations, but it's causing a problem for the wind segment.
High water can be shunted around the dams through spillways, but that subjects fish to dangerous levels of nitrogen gas bubbles in the churning water, causing something like the bends that human divers sometimes get. Milstein said water quality in the basin now violates standards in both Oregon and Washington state, a key part in a long-running legal battle over running the dams.
Milstein said a federal court order recognizes that the agency has little choice when the water is so high and must put dangerous volumes through the spillways. "There's no question that fish are being harmed," he said.
But a salmon advocate said the high flows are giving young fish, known as smolts, a quick ride to the ocean, like the one their forebears got before the dams were built. That gives more fish a chance at surviving to reproduce a few years later.
"The benefits of moving those little guys quickly to the ocean, as opposed to letting them get lost in the reservoirs, are greater," said Pat Ford of Save Our Wild Salmon.
The Bonneville Power Administration markets about a third of the region's power, from 31 dams and from a nuclear plant on the Hanford nuclear reservation in eastern Washington. It manages transmission for about three-quarters of the region's power, but the high water in the river system has a spillover impact on plants not tied to its system.
Because the region is awash in federal power, the wholesale price of electricity on the spot market is effectively zero.
That enables owners of fossil fuel plants to shut down, save on fuel costs and still supply their customers with federal power. Thermal plant owners in the basin often schedule maintenance and repairs to coincide with the spring rise.
This year's rise is the largest since 1997, but only the 7th largest in the past 40 years.
In the past decade, wind farms nurtured by government regulations and tax benefits have come on-line in large numbers _ and are expected to double within the next decade. But they don't share the operational benefits of fossil fuel plants.
The wind is free, so they can't save on fuel, and many rely on tax credits pegged to their production. That's why they've objected to being shut down without compensation. They say the shutdown isn't necessary, will cost them millions in tax benefits and will discourage investment in the business.
Traditional customers of the Bonneville Power Administration, such as public power districts prominent in Washington state, say they'd have to bear that cost so they object to the idea of compensating wind farms.
In anticipation of high water, the Hanford nuclear plant was shut down weeks ago for refueling. The agency sells power wholesale from a variety of fossil fuel plants _ coal and natural gas _ and markets power from a number of smaller sources, such as landfills and sawmills making power from biomass. Milstein says they, too, would have been subject to shutdowns if they were operating.