Wastewater Treatment Plant Solar Array

Harnessing the Sun at the Wastewater Treatment Plant

Installing solar panels at the treatment plant

About the Solar ArrayGresham Wastewater Treatment Plant

See an aerial view of the solar array

Gresham’s wastewater treatment plant has solar power at the facility, which operates 365 days a year cleaning and reclaiming 13 million gallons of wastewater a day.

Through a successful public-private partnership with SunEdison and REC Solar, the City installed a 419 kW solar array at its wastewater treatment plant at no cost to ratepayers.

The solar power is expected to generate 7% of the plant’s annual electricity, and at the height of summer the system could produce electricity at its full capacity – enough to run half the plant or power 43 homes for one year.

REC Solar installed 1,904 ground-mounted solar panels on an acre and a half of land at the plant.

This is the first solar plant of this scale for Gresham and shows the City's continued promise for more renewable energy solutions.

Solar Benefitssun shining on solar panels

  • Clean, quiet and visually unobtrusive in nature, solar energy plants don't emit pollution or make sound.
  • Uses little to no water in the production of zero-emission electricity. 
  • Can be placed in virtually every geographical region, because the sun is available everywhere.

By adding solar power, the wastewater treatment plant is 75% percent sustainable, with 50 percent of its power provided by converting methane gas produced on site to energy, and another 18 percent from Clean Wind power purchased from PGE.

Through a 20-year power purchase agreement with SunEdison, the City did not pay any of the project installation cost, but will buy the solar power it produces. SunEdison will maintain and operate the solar array.


For information about the solar array contact Michael Nacrelli at 503-618-2751 or Michael.Nacrelli@GreshamOregon.gov