Mariposa Biomass Project
Demonstrating a 2.4 MW forest waste-to-energy facility using the innovative "WoodRoll" technology.
Mariposa County Resource Conservation District (MCRCD)
Recipient
Mariposa, CA
Recipient Location
4th
Senate District
8th
Assembly District
$307,312
Amount Spent
Active
Project Status
Project Update
To complete this project within the EPIC grant term, the Mariposa Biomass Project team requested and was approved to change the technology provider to West Biofuels. West Biofuels designed a 3 MW thermal oil plant within the Conditional Use Permit conditions of the previous plant and within the same footprint. The Mariposa Planning Commission approved the project's Conditional Use Permit, leading to the provision of its grading and building permit. The recipient is working to start construction in the second quarter of 2025. The project also received three additional grants in 2024: a U.S. Fire Service Wood Innovations grant, a CAL FIRE Wood Products and Bioenergy grant, and a US Department of Energy Office of Clean Energy Demonstrations grant (selected for negotiations).
The Issue
About 65% of the homes in Mariposa County are at the 2,000 to 6,000 ft. elevation range in the conifer or mixed conifer zone and are at risk of wildfires and falling trees. There is a need to manage excess vegetation and a need to demonstrate advanced technologies that can economically convert woody biomass while meeting emission standards. However, no commercially proven technology has the flexibility in both the feedstock and fuel outputs. Larger scale biomass plants have difficulty scaling to below a 3 MW size, while small-scale pyrolysis-based systems that use a reciprocating engine have high maintenance costs and low reliability and availability.
Project Innovation
This project is designing and constructing a thermal oil biomass-to-energy conversion facility for forest wood waste that will have a capacity of 3 MW annually and produce between 15,000 to 18,500 MWh annually of renewable, community-scale, grid-connected electricity. The project demonstrates and optimizes this forest waste bioenergy technology and assesses the performance characteristics and best practices when using wood waste from forest management as feedstock. The project is in Mariposa, CA -- often referred to as ground zero for the tree mortality disaster -- and will use forest biomass obtained from high and very high severity fire hazard zones.
Project Benefits
The Mariposa Biomass Project has partnered with West Biofuels to demonstrate the successful conversion of forest wood waste into energy and biochar. The small, local plant within an area with significant amounts of fuel reduction and vegetation management will improve the economics of converting biomass, reduce transportation costs, and protect residents from the effects of open pile burning or high intensity wildfire by removing fuels and providing an alternative to pile burning. The US DOE grant will help to fund high level professional management of the plant shared among three small scale community plants, allowing the team to hire qualified personnel to split management time and costs among the plants. Manageable operating and maintenance costs will allow the Mariposa Biomass Project to be a financially successful small-scale forest biomass facility that can be replicated in other rural areas with access to sustainable forest biomass supplies.

Environmental Sustainability
The proposed facility will provide community and state benefits, including forest ecosystem protection (due to removal of dead trees and excess forest growth that can lead to catastrophic wildfires), watershed protection, and air quality improvements. Benefits include low-carbon, reliable energy, reduced carbon emissions, and a local market for biomass from forest thinning and vegetation management projects.
Key Project Members

Melinda Barrett
Subrecipients

West Biofuels, LLC

Mariposa Bioenergy LLC

Match Partners

West Biofuels, LLC

Mariposa County Resource Conservation District (MCRCD)

Mariposa Bioenergy LLC
