The demand for electricity on Mercer Island is not expected to increase significantly during the period covered by this plan. While the Island’s total electricity consumption was 164,713,778 KWH in 1998, the Island’s total electricity consumed was 174,352,420/KWH, or an average of 18,234/KWH per customer, in 2013.
PSE’s planning analysis has identified five alternative solutions to address transmission capacity deficiency identified in the “Eastside Needs Assessment Report – Transmission System King County” dated October 2013. Each of these five solutions fully satisfies the needs identified in the Eastside Needs Assessment Report and satisfies the solution longevity and constructibility requirements established by PSE. These five solutions include two 230 kV transmission sources and three transformer sites, outside of Mercer Island. PSE states construction is anticipated to begin in 2017 and completed in 2018.
With one exception (see Policy 6.1), the only significant changes in PSE’s Mercer Island facilities will come from efforts aimed at improving system reliability.
The issue of system reliability, which is the subject of a Memorandum of Agreement (MOA) between the City of Mercer Island and PSE, will require considerable attention over the next several years. The MOA sets policies for identifying locations where power lines should be relocated underground and describes strategies for funding undergrounding projects. There is a reoccurring issue of unreliability is unresolved and needs to be addressed.