While the big new power lines planned by PSE are not anywhere near Mercer Island, they will serve the growing energy needs of Islanders as well as the Eastside, power planners say.

Puget Sound Energy will host another round of open houses for its Energize Eastside project next week, including one in Bellevue on Thursday, Sept. 11.

PSE is about two-thirds of the way through its community outreach goals for the project, and citizen advisory committees have reduced the number of routes being considered to run 230kV lines between Redmond and Renton down from 18 to 11.

Energize Eastside Senior Project Manager Jens Nedrud said all have their challenges and tradeoffs. The goal is to link the lines to an additional transformer to increase capacity on the Eastside, as the four existing in the area are beginning to feel the strain, he said. A fifth transformer is expected to handle capacity needs into 2030.

“People really get that there’s growth,” Nedrud said. “You’re always going to have a small portion that say, ‘No, we’re not growing.’”

The energy company has been scrutinized by several neighborhoods along proposed routes for the Energize Eastside project that contend PSE is not in any eminent danger of reaching capacity here. PSE estimates it could reach winter peak capacity by 2017. It also points to a Puget Sound Regional Council report that estimates a 70-percent growth in employment in the region by 2040.

Nedrud said opponents are correct that new power lines will feed into Canada, however, that will amount to about 3-8 percent of production.

“The whole project is based on the need to keep the lights on the Eastside area,” he said.

Many still argue conservation efforts could shore up the need for increasing capacity on the Eastside, but a study commissioned by PSE shows only 2,300 of its 1.3 million customers are currently taking such conservation actions, said Gretchen Aliabadi, Energize Eastside communications initiatives manager.

She said residents within proposed Energize Eastside routes vary in their opinions about erecting power poles between 90-125 feet in height, depending mostly on whether they would obstruct their vista views. Aliabadi added taller poles allow PSE to use fewer poles to run lines farther.

Nedrud said undergrounding at 230kV has existed for the past 10 years, but its technology is still too new and expensive for PSE to seriously consider. Power Engineers was hired on to consult on undergrounding options, he said, determining it could cost up to $28 million a mile for construction, as opposed to $4 million a mile for overhead lines. PSE wouldn’t recover that cost through its utility rate, because the Washington Utilities and Transportation Commission requires local jurisdictions to cover the difference between undergrounding and overhead lines.

“We don’t know how many people would be paying for it,” he said, adding a tax would need to be levied for an undergrounding option.

Aliabadi said she understands not every Eastside resident will end up agreeing with PSE that the project is necessary, however, the state UTC will review the Energize Eastside once completed. If it is not deemed necessary, the energy company will not be able to recover its costs, which are estimated as high as $300 million.

An open house will be held between 6 and 8 p.m. Thursday, Sept. 11 at the Bellevue Hilton at 300 112th Ave. S.E.