Evaluation of biomass conversion technologies: new publication released

We recently completed work on the Waste to Wisdom project that examined the entire supply chain of converting forest waste residues into bioenergy and wood products. The Center’s role was to evaluate equipment that produces biochar, torrefied biomass, electricity, or densified wood briquettes using forest residues as the input feedstock. Collaborators from Humboldt State’s Forestry Department analyzed the upstream collection of forest biomass, and experts from the U.S. Forest Service conducted a lifecycle assessment and economic analysis of the supply chain.

SEM biochar image

SEM biochar image (taken at the HSU CNRS Core Facility)


Data collected by the Schatz Center during field tests of biomass conversion equipment were used to:

  • identify optimal process conditions,
  • specify feedstock limitations,
  • measure emissions,
  • evaluate product quality, and
  • recommend design improvements to equipment manufacturers.

Results and conclusions from the entire project are presented in a special issue of Applied Engineering for Agriculture, published in February 2018. Four principal investigators, including Schatz Center Director Arne Jacobson, summarized the project’s objectives and major conclusions in the introduction article to the special issue. Engineers from Schatz authored four papers, on biochar production, torrefaction and briquetting, and gasification of forest residues:

Collaborators at the U.S. Forest Service and the Consortium for Research and Renewable Industrial Materials (CORRIM) used the results collected from testing activities to conduct economic and environmental life cycle analyses of biomass conversion technologies. Field measurements from the Waste to Wisdom project will also be included in our current California Biopower Impacts project, which is evaluating the environmental impacts associated with utilization of forest-derived woody biomass for electricity generation.

This work could not have been completed without close collaboration between our primary industry partners: Biochar Solutions, Inc., Norris Thermal Technologies, and Pellet Fuels Institute, who provided the testing equipment. Other partners that provided key support include the Green Diamond Resource Company, the Redwood Forest Foundation, Inc. (RFFI), All Power Labs, Bear Mountain Forest Products, Colorado Biochar Resources, Pueblo Wood Products, California Redwood Company, North Coast Air Quality Management District, RUF Briquetting Systems, and OMNI Test Labs.

Stack of three briquettes; different colors represent combinations of temperature and time.
Forest residues were converted into torrefied briquettes in the demonstration-scale torrefaction plant. The perceptible differences in color and density reflect combinations of reaction temperature and residence time.

Schatz Energy in brief: climate-smart infrastructure and sustainable bioenergy

The Union of Concerned Scientists just released a new white paper on “climate-smart” infrastructure in California, citing the Blue Lake Rancheria (BLR) microgrid as a prime example of infrastructure built to safely sustain communities during climate change.

The Roundtable on Sustainable Biomaterials (RSB) adopted a revised Standard for Advanced Fuels this month at the delegate meeting in Vancouver, Canada. Kevin Fingerman (second from left below) is an RSB board member, and is the principal investigator on the California Biopower Impact Project here at the Schatz Center.

California Biopower Impact Project: creating a Life Cycle Assessment for bioenergy systems

The Schatz Center recently began work on the California Biopower Impact (CBI) Project, supported by a three-year $1,000,000 grant from the California Energy Commission. Our project will investigate the impacts associated with utilization of forest-derived woody biomass and agricultural residues for electricity generation. If managed properly, bioenergy could support sustainable forest management activities while also advancing California’s Renewables Portfolio Standard goals. However, there are also legitimate concerns surrounding the climate, air quality, soil fertility, and ecosystem health implications of improperly managed bioenergy systems. Before biomass energy can be responsibly pursued as a means to achieve forest management and renewable energy goals, additional research is needed to firmly establish the climate impact and broader environmental performance of forest and agricultural bioenergy.

Our central effort under the CBI Project will be the creation of a Life Cycle Assessment (LCA) greenhouse gas emissions accounting tool that will allow stakeholders in California to evaluate the impacts of different bioenergy policy and technology pathways in the state. Along with greenhouse gas balances, the project team will address additional critical environmental impacts that can be associated with bioenergy – including altered risk or severity of wildfire, soil fertility and carbon stock reduction, changes to air quality, and potential impact on habitats and biodiversity.

Pile of small branches


Woody biomass

Key study areas and outputs:

  • Assessment and mapping of net recoverable biomass that could be utilized for electricity generation. This analysis will focus on agricultural residues as well as forestry residues and fire reduction thinning material per the California Governor’s state of emergency brought on by the record numbers of drought and beetle- killed trees in the Sierra Nevada range.
  • Conduct a landscape-level probabilistic assessment of the fire risk implications of sustainable forest harvesting. Fire behavior under future climate scenarios will be simulated using the Pacific Northwest variant of the USDA Forest Vegetation Simulator (FVS) in combination with the Fires and Fuels Extension and Climate Extension modules.
  • Develop and demonstrate the California Residual Biomass-to-electricity Carbon Accounting Tool (CaRBCAT). This tool will improve on existing frameworks representing California’s unique bioeconomy context, offering improved spatial resolution, rigorously characterizing uncertainty, and offering a high degree of specification regarding supply chain characteristics. Users will be able to specify harvest practices, feedstock collection and handling methods, post-harvest treatments, feedstock management pathways, conversion technologies, and other characteristics.
  • Characterize and report on key environmental impacts of residual biomass mobilization such as changes to soil nutrient balance and carbon stock, air quality effects from altered black carbon and criteria air pollutant emission profiles, and impacts to biodiversity.
  • Assess potential to offset some harvest and supply chain costs through payments for ecosystem services and similar environmental market schemes.
  • Identify best management practices to improve bioelectricity system net GHG balance as well as to optimize performance with respect to fire risk, soil health, air quality, and habitat conservation. Develop and disseminate science-based policy recommendations that support implementation of these practices in bioelectricity supply chains.
Kevin Fingerman headshot


Kevin Fingerman, CBI Project Principal Investigator

Kevin Fingerman is a Schatz Center Faculty Research Associate and an Assistant Professor of Environmental Science & Management at Humboldt State University. His research employs life cycle assessment and simulation modeling tools to evaluate the broad-based impacts of bioenergy and transportation energy systems. He has also worked extensively on the water/energy nexus and on bioenergy policy.

Kevin serves on the board of directors of the Roundtable on Sustainable Biomaterials and, prior to joining HSU, he worked in Rome for the United Nations Food and Agriculture Organization. He holds MS and PhD degrees from UC Berkeley’s Energy & Resources Group.

Biomass Utilization Feasibility Study for the Karuk Tribe of California

The Schatz Center is assisting the Karuk Community Development Corporation (KCDC) with a biomass utilization feasibility study. The Karuk Tribe of California (KTOC) has aboriginal territory encompassing the Klamath River and Salmon River watersheds in Northern California. These lands are heavily forested and have been adversely impacted by postcolonial land use practices like timber production and wildfire suppression. Large, destructive wildfires have become an annual occurrence in and around Karuk territory, and there is widespread agreement among land managers that forest practices in the region need to change. The KTOC is leading this change through eco-cultural revitalization efforts that involve putting beneficial fire back on the land and restoration of traditional oak woodlands. Within this context, there is a role for utilization of biomass residuals that are removed through mechanical treatment. The Schatz Center is evaluating economic development opportunities for the KCDC to utilize forest residuals.

The overall goal of the project is to determine the feasibility of using local, renewable biomass resources that are available to the KTOC to generate power, heat, or products, while creating jobs, fostering environmental stewardship, and providing benefits to the Tribe’s economy. The objectives of this project are to determine the resource availability, identify technologies that could be implemented, and calculate the financial viability of potential projects.

This project is currently active and is funded by US Department of Interior Indian Affairs Energy and Mineral Development Program. We expect to complete the project by the second quarter of 2018.

Improving a Biochar Production System in Mendocino County

by Kyle Palmer and Mark Severy

For the past three years, the Redwood Forest Foundation, Inc. (RFFI) has produced biochar from small-diameter tanoak trees collected from thinning operations in Mendocino County’s Usal Forest. The Usal Forest ecosystem was disrupted by industrial logging operations throughout the 20th century. Tanoak’s rapid regrowth dominated canopy light, and interfered with redwood repopulation. RFFI is selectively removing tanoak to create the natural space that redwood needs to flourish, and converting the tanoak into biochar to help fund their restoration work.

Biochar, a blackened, solid biomass produced at temperatures above 500°C in the absence of oxygen, is used primarily as a soil amendment to increase water holding capacity, reduce nutrient leaching, and improve conditions for microbial life. (Learn more about biochar on the Waste to Wisdom site.)

RFFI’s biochar production operation has balanced on the edge of technical and economic feasibility due to the high moisture content of the tanoak feedstock and the labor costs required to operate the machine. In 2016, the Schatz Energy Research Center addressed moisture content by installing a biomass drying system that uses waste heat from the biochar machine. This year, the Schatz Center is working to reduce labor hours while improving safety and productivity, by automating key processes on the machine.

A SEM photo shows the porosity of biochar


The highly porous structure of biochar is shown through scanning electron microscopy (SEM) at 600x magnification. This SEM image was taken by Murielle Manka and Marty Reed, using the Humboldt State CNRS Core Research Facility’s FEI Quanta 250 ESEM. The Quanta was obtained in 2012 via a Major Research Instrumentation grant from the National Science Foundation.

In July and August, research engineers Kyle Palmer, Andy Eggink and student research assistant Murielle Manka evaluated baseline labor hours, biochar production rate, and biochar quality produced with the existing system. Throughout these tests, real-time data were collected for gas flow, composition, and electric power demand to help develop the control schemes. Monitoring and automation equipment are currently being installed and performance improvements will be validated in the coming months.

The preliminary results from this study were presented in early September by Murielle Manka and Schatz Director Arne Jacobson at the Agricultural Research Institute’s (ARI) principal investigator’s meeting in Sacramento. Validation test results analyzed this autumn will quantify benefits of the automation system, including any reductions in labor, increases in throughput, and changes in biochar quality.

This material is based upon work supported by California State University Agricultural Research Institute and a grant from the U.S. Department of Energy under the Biomass Research and Development Initiative program: Award Number DE-EE0006297.


Murielle Manka and Arne Jacobson present biochar testing results


Murielle Manka and Arne Jacobson at the September 2017 ARI meeting in Sacramento