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Puget Sound Energy substation project

Four Corners substation

Spring 2010 project completion
  • Construction of the new $6.8 million electric distribution substation was complete on Dec. 11, 2009
Project overview

PSE has built a new electric distribution substation to help meet increased demand for electricity in the Maple Valley area. Our new Four Corners substation is located at 27430 Maple Valley Black Diamond Road SE (State Route 169). The substation increases electric capacity and reliability to customers in the Maple Valley area. Our substation includes one 25 megawatt (MW) transformer and has the space to add a second 25 MW transformer, which will allow PSE to double the capacity in the future without changing the substation footprint.

Construction underway
the Four Corners substation
in Maple Valley

What is a substation?

Substations are critical links in the electricity distribution system, containing utility circuit protection, voltage regulation, and equipment that steps down higher voltage to lower voltage. Before reaching homes and businesses, power is routed through our transmission system to a substation where it is changed to a lower voltage that can be utilized by customers.


Download full-size map

Project Map
(367 KB PDF)

Download information

Download these PDF files for more detail on PSE's Four Corners substation project.
Press release (12/14/09)
News coverage(07/02/09)
Community ad
Press release (04/22/09)
Revised construction notice
Presentation, April 2008
Meeting invite
Fact sheet
Project Map
Landscape design
South elevation design
West elevation design
Presentation, Jan. 2008