Wildfire Shuts Down Seattle City Light’s Skagit Hydropower (The Reason Is Surprising) | KUOW News and Information

Wildfire Shuts Down Seattle City Light’s Skagit Hydropower (The Reason Is Surprising)

Aug 25, 2015

Eight fires have burned more than 4,000 acres in Washington’s North Cascades. The largest of the fires has damaged transmission lines, leading Seattle City Light to shut down power generation at three dams on the Skagit River.

The utility is losing $100,000 in revenue each day that the lines are down. Conditions have remained unsafe for repair crews to work on the power lines.

Q: Have the fires damaged the dams?

A: The dams themselves are OK as of right now and Seattle City Light is letting water spill over them to generate only enough power to meet minimal local needs. The Goodell Fire has damaged six towers on the main transmission line that sends power to Seattle and the broader grid. But more surprisingly, it’s the smoke that led Seattle City Light to shut down transmission. It was so thick that the particles in air were conducting electricity. Seattle City Light spokesman Scott Thomsen explains:

“You would have an arc of electricity that you could see bright flashes and sparks coming off the line as the electricity is trying to get to ground and it’s trying find a faster path to get to ground than going down the metal wire. So if there’s enough material around it that can conduct electricity and gives it a shorter path to where it wants to go, it will follow that path.”

Q: Will the lights stay on?

A: Yes. Seattle City Light is buying power from elsewhere on the grid to supply its customers. That’s lead to costs of $100,000 per day - close to $500,000 since power from the dams was curtailed last week.

Q: Will this cost ratepayers more money?

A: Probably. Seattle City Light sells surplus electricity on the grid, generating millions of dollars in revenue for the publicly owned utility. But so far revenues are $25 million below target for the year. The meager snowpack last winter led to less hydropower generation this season.

The utility was a net purchaser of electricity in July instead of a seller. Seattle City Light says it’s too soon to do the numbers in terms of total losses for the utility, but that climate change, and the wildfires, present a very real costs to the utility and ratepayers could face surcharges.

Thomsen: “This is reducing our capacity to generate electricity that we sell, either to our own customers or to other utilities and so those costs do have an impact. We’ll have to see how long this goes to determine how big that impact is but it’s certainly something that is going to have an effect on what we’re going to see by the end of the year in terms of how our budget is worked out.”

Q: Are fires affecting other transmission lines in the Northwest?

A: The Bonneville Power Administration reports five wildfire-caused power outages - four in Washington and one in Montana. The power lines mainly serviced rural parts of the region and power was restored relatively quickly.

Kevin Wingert, a spokesman for BPA, said it is keeping an eye on things.

“We are very actively monitoring the situation. We’ve not had a major disruption or event on the system as a result of fire but we’re very cognizant that the situation and conditions can change particularly in this dry hot summer we’ve been seeing.”

Q: How are things looking this fall? How is Seattle City Light planning for climate change?

A: Seattle City Light employs a climate expert to lead the utility in planning for climate change. You can watch a video from our previous coverage of climate change and hydropower with the utility’s climate adviser Crystal Raymond:

Looking ahead, with an El Nino year in the works, that could mean a warm, dry winter in the Northwest. This past year, Seattle City Light filled its reservoirs higher and earlier than normal to prepare for a long dry summer without the usual flow from melting snowpack.

Scott Thomsen: “This year the inflows measured at the Skagit were the lowest since they started recording inflows in 1910. What little water that was coming in was melting glacier. That combined with a lack of rain through the summer meant very little water to work with in terms of generating electricity.”

And one more thing, all that ash from the fires could darken the glaciers and speed melting, Raymond explained in an email:

“We cannot look at the impacts of climate change in isolation because many can happen together when they have the same underlying cause. Another one is all the dark ash from the wildfires being deposited on the glaciers in the North Cascades during a summer when they will already be losing a lot of mass because of the abnormally warm temperatures.”

Listen to Ashley Ahearn's conversation with KUOW host Kim Malcolm about wildfires and the electrical grid: