Challenges of bringing power to Sisters

Engineers and planners at Central Electric Cooperative (CEC) are scrambling to keep up with the demand for electrical power in the fast-growing Sisters area.

According to CEC account records, Sisters is just behind Redmond as the cooperative's third largest service area. Redmond has 5,920 total active services (including Eagle Crest), while the Sisters area carries 5,237 active services.

Metropolitan Bend is the largest, with 12,048 active services.

"We're experiencing tremendous growth," said CEC Operations Manager Jeff Spencer.

He estimates the growth in the Sisters area to be about 6 to 7 percent per year; that growth rate is expected to continue indefinitely. CEC planners anticipate a doubling of the peak load within 10 to 15 years.

"We're preparing for it," Spencer said.

While much of the growth comes in the form of new development, remodels and improvements on existing properties in Sisters, Black Butte Ranch and other outlying areas also add to the work load.

"Probably 30 percent of my work load (in Sisters) is what we call service upgrades," said Senior Staking engineer Dan Dingman.

Those upgrades are not reflected in statistics on growth in service accounts.

There is a project underway right now to help CEC cope with higher electrical demand at the far western end of the service area -- an upgrade to the Black Butte Ranch substation.

"We're doubling the capacity of that substation even as we speak," Spencer said.

Transmission of power from the Bonneville Power Administration site in Redmond out to Sisters and beyond is a growing concern for CEC engineers and planners.

CEC has sought to upgrade its Jordan Road line, which, in conjunction with a line along Highway 126, carries electricity into the Sisters area.

That upgrade has been caught up in a legal dispute with the Cyrus family of Sisters and plans have been remanded to Deschutes County for more work.

According to CEC, the upgrade is needed to improve load capacity and reliability.

"That line needs to be upgraded to relieve the load from the Highway 126 line," Spencer said. "Last year we had by far the biggest increase in peak load ever on that line. We're close to our minimum voltage levels."

That's a concern as winter looms.

"Most of our load is electrical heat," Spencer said. "If we get a real cold snap, we're going to see peak loads we haven't seen before."

Spencer emphasized that brownouts are possible at the far end of the line -- Black Butte Ranch and Camp Sherman -- but they are unlikely. It would take a pretty severe Arctic blast to cause that. However, the probability of brownouts will grow year by year as more demand is put on the system.

To counter that potential, crews have recently installed voltage regulators at Suttle Lake and Camp Sherman.

"Because we know this (Jordan Road Line) project has been delayed, we've taken countermeasures," Spencer said.

CEC believes it's still ahead of the curve in keeping power flowing to Sisters. That could change.

"We're right on the edge," Spencer said.

"This system improvement needs to be completed soon and if it's not, we'll fall behind the curve."

If the project cannot go through, CEC will increase voltage on the Highway 126 line -- a project that will have to be done in any case.

However, without the Jordan Road upgrade, the system would lack adequate back-up capability in case the Highway 126 line went down.

Not only are more people requiring electric service in the Sisters area, the traditional uses have changed.

"So many people have computers at home, they can't tolerate a 'blink,'" Spencer noted.

A blink is a momentary, almost imperceptible interruption in power flow.

To accommodate the greater sensitivity of computer equipment, CEC, like other electricity providers, has had to change the way its breaker systems operate so that breakers can open and then close and settings have been changed to allow fewer momentary outages.

Growth has changed the way CEC works, as well.

While the workload has grown, the permanent work force of 80 to 85 has only increased by a couple of people over the last several years. (One of those is a new engineer for the Sisters area).

Instead of hiring, "to counter the extreme growth, we use more contract personnel," Spencer said. "That allows us to ramp up our work force during peak work times."

As growth in the Sisters area continues to boom, those peak work times are becoming more and more frequent.