HORSE digester PSE pilot project ends


The High-solids Organic-waste Recycling System with Electrical output (HORSE) biodigester has completed its two year pilot project on Bainbridge Island. We want to thank our partners, Impact Bioenergy, Harbour Public House, and the four restaurants at Pleasant Beach Village, for making this project possible.

PSE and Impact Bioenergy initially partnered with Harbour Public House in 2016 for the first half of the pilot. The demonstration turned food waste into on-site energy generation and produced nutrient-laden, liquid fertilizer. 

In late 2017, the HORSE moved to Pleasant Beach Village to feed on the waste from the four restaurants in the Village. This second opportunity allowed the partners to further test the technology.

The digester is designed to generate 2,550 kilowatt hours of energy per year, according to PSE. The system’s technology can generate the energy equivalent of one barrel of crude oil from 2,900 pounds of food scraps. It also generates 5,400 gallons per year of nutrient-rich fertilizer, which has so-far been supplied to local farms. It is a zero-waste system, which also avoids the need to truck organics off the island.

Impact Bioenergy, based in Seattle, developed the self-contained, portable biodigester and continued to monitor the HORSE on Bainbridge Island throughout the entire pilot project. They are continuing to look for other partners on Bainbridge Island. 

The two-year effort was a natural extension of PSE’s ongoing interest in developing alternative sources of energy that can then power our renewable energy programs for our customers.