Addressing California's wood waste crisis
California is facing an unprecedented crisis whereby millions of tons of wood waste from wildfire prevention efforts are being piled and burned or left to decay in forests, increasing the state’s emissions and undermining broader forest resilience goals. Despite some progress towards establishing a circular economy to collect and process the residues into low-carbon products, these efforts have not kept pace with the scale of the problem. The result is that local communities are now turning to strategies including exporting the state’s forest residues to burn in coal-fired power plants in Asia and Europe.
In this blog we examine the potential for California to deploy a portfolio of next-generation biomass technologies, including wood products such as mass timber, clean fuels such as hydrogen and sustainable aviation fuel, and carbon dioxide removal. These non-combustion options are widely identified in peer-reviewed science and by the California Air Resources Board as needed to achieve a net-zero emissions goal. A non-combustion wood waste strategy can reduce local air pollution, increase in-state jobs and help pay for forest treatments – which have a price tag well in excess of the state’s annual wildfire budget. New policies that could drive technology uptake include procurement standards for wood products, strategies to enable long-term feedstock supply from public and non-industrial private lands, and revenue incentives for forest biofuels and biomass carbon removal pathways.
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California is grappling with a wood waste crisis. Hundreds of millions of dead and dying trees litter the Sierra Nevada and North Coast alongside millions of tons of residues that have already been piled and left to decay. In its 2022 Scoping Plan, the California Air Resources Board (CARB) identified needing to increase the pace and scale of forest treatments to 2.3 million acres per year to reduce the risk of severe wildfire (and the substantial emissions that come with it). This scale of action will drive further increases in forest biomass, adding to the millions of tons of agricultural residues also generated each year in the Central Valley that are primarily field burned and a key contributor to poor air quality in the region.
Finding carbon-beneficial end-uses for wood waste has become critical. Yet, current options face key drawbacks. Large-scale direct combustion is the main outlet, although these facilities have been shown to increase local air pollution. Biopower is also a relatively expensive form of electricity generation, resulting in an increased cost to ratepayers compared to alternative energy resources.
Lacking options, yet faced with an ongoing and considerable public safety and wildfire threat, local communities have turned to strategies including converting residues into pellets to ship overseas for combustion in power stations in Asia and Europe. This is, in a general, a very poor climate strategy, with the potential to be the same if not more polluting than conventional fossil fuels. A strategy to sustainably manage the state’s biomass waste is needed to help avoid carbon and air pollution from field burning, decay and wildfire, replace and phase-down our reliance on fossil fuels with cleaner alternatives, and drive new manufacturing and job opportunities in rural and tribal areas throughout the state.
New technologies offer a path
A portfolio of new and advanced biomass technologies have emerged in recent years that could provide a solution to the current problem. These non-combustion options are cleaner and more scalable than traditional technologies and have been identified by CARB and peer-reviewed research more broadly as needed to achieve net-zero emission ambitions. The three main technology categories include:
Wood products
Durable wood products such as mass timber, derived from medium-sized merchantable logs, as well as other products such as wood fiber, derived from biomass waste, present an opportunity to repurpose forest biomass into building materials. These products not only sequester carbon but, in the case of mass timber, also provide an alternative to carbon-intensive construction materials like concrete and steel, which can reduce the embodied carbon of buildings. An expansion in the use of wood products could support the state’s affordable housing goals with locally-sourced, carbon-beneficial materials.
Clean fuels
Clean liquid and gaseous fuels are widely shown as playing a key role in net-zero emission portfolios by decarbonizing end-uses that cannot or are unlikely to be electrified, such as aviation, shipping, some on-road transport, and certain industrial applications. Biomass is one of the only non-fossil options to generating clean fuels (Figure 1) – which is why energy systems models regularly identify needing to expand biomass-fuels as a key technology pathway for delivering long-term climate goals.
Figure 1. This diagram identifies three key pathways to clean fuels. Blue hydrogen is still derived from fossil fuels (natural gas) via steam methane reformation with carbon capture and storage (CCS). Power-to-fuels (electrolysis) and biomass-to-fuels are the available non-fossil pathways. Power-to-fuels emissions depend on whether electrolysis projects rely on grid-connected electricity. Biomass-to-fuels emissions depend upon the source feedstock (waste vs. energy crop) and the application (or not) of CCS.
Examples of needed clean fuels include hydrogen, sustainable aviation fuel and renewable natural gas, which can be derived from waste biomass via non-combustion technologies such as gasification and pyrolysis. In the 2022 Scoping Plan, CARB identified needing to scale up clean hydrogen by 1,700x compared to current levels of production, and for 80% of aviation fuel demand to be met with sustainable aviation fuel by 2045. There is currently no clear pathway to meet these targets.
Carbon dioxide removal
Carbon dioxide removal (CDR) – here referring to the process of removing carbon dioxide (CO2) from the atmosphere and permanently storing it – is also shown as a required climate strategy to achieve a net-zero emissions goal. Similar to clean fuels, there are limited options to deliver permanent CDR. Biomass is one key option where, for example, biomass could be converted to hydrogen via gasification and the CO2 could be captured at the point-source and then stored underground in geologic formations. This pathway – sometimes referred to as “BECCS-H2” – has been identified as a priority technology pathway in that it provides both a clean fuel and CDR. Other potential biomass carbon removal options could include directly injecting bio-oil underground, biomass burial, biochar, and more (Figure 2).
Figure 2. This diagram, developed by researchers from World Resources Institute, identifies paths to biomass carbon removal (dark green, far right-hand column) with accompanying products (light green, second from far-right). Although this article focuses on agricultural and forest wastes, perennial crops on marginal lands and municipal solid waste could also be targeted for carbon removal.
AB 1279 (Muratsuchi) identified that up to 15%, or about 65 Mt/yr, of California’s climate mitigation could come in the form of CDR. In its 2022 Scoping Plan, CARB identified needing 75 Mt/yr of CDR to compensate for land sector emissions and to achieve a net-negative economy (-3 Mt/yr) by 2045. In both Getting to Neutral and Roads to Removal, Lawrence Livermore National Laboratory scientists identified biomass carbon removal as California’s largest and least-cost technological CDR opportunity.
Policy considerations
California has taken some important initial steps to address the wood waste crisis. Key initiatives include joint state and federal commitments to increase forest health treatments; California’s Wildfire & Forest Resilience Action Plan; as well as multiple grant and/or financing programs, including the Department of Conservation’s forest biofuels pilot program, the Office of Land-Use and Climate Innovation’s feedstock supply pilot program, CAL FIRE’s wood products program, and IBank’s Climate Catalyst Fund.
However, the scale of the problem far outstrips these starting programs. We identify potential policies that could be considered as part of broader plan and vision for a sustainable bioeconomy in California that generates new high-skilled and high-paying jobs, helps to reduce wildfire and air pollution, and helps to achieve considerable progress towards the state’s climate goals. These policies seek to address key barriers to deploying advanced and clean non-combustion biomass technologies in California:
Establish procurement standards for wood products, such as mass timber, wood fiber and biochar, that can reduce the embodied carbon in construction materials and buildings. This could start with application to California State government infrastructure projects as identified by the Joint Institute for Wood Products Innovation.
Address key barriers to long-term feedstock supply from public and non-industrial private lands, including by performing regional biomass availability assessments and increasing funding to and expanding the Office of Land-Use and Climate Innovation’s feedstock supply program.
Develop a biomass tracking system to trace and authenticate waste biomass origins and assure environmental sustainability for the purpose of a range of new and existing programs and end-uses including wood products, clean fuels and carbon dioxide removal.
Develop an incentive pathway, such as a design-based pathway, and/or guidance under the Low Carbon Fuel Standard for fuels created using waste feedstocks from forest health projects. An existing life cycle assessment tool being further developed by the Schatz Energy Research Center and Cal Poly Humboldt may offer a starting point.
Develop and adopt biomass carbon removal protocols that identify eligible biomass carbon removal pathways for the purpose achieving the state’s carbon dioxide removal targets as identified in AB 1279 and the 2022 Scoping Plan.
Conclusion
California faces an unprecedented wood waste crisis that, if left unaddressed, could substantively undermine the state's forest health and wildfire risk reduction efforts. In contrast, a strategy to mobilize these residues could enable forest treatments at scale and generate considerable carbon and air pollution benefits as well as economic development in rural and disadvantaged communities. Clean and advanced non-combustion technologies present a new opportunity and era on biomass management and have been identified by the California Air Resources Board as needed to achieve a net-zero emissions goal. Key policies to enable priority non-combustion pathways include procurement standards for wood products, strategies to enable long-term feedstock supply from public and non-industrial private lands, and revenue incentives for forest biofuels and biomass carbon removal pathways.
For more information, please contact Sam Uden (sam@netzerocalifornia.org) and Amanda DeMarco (amanda@netzerocalifornia.org).