Biomass in California: Is it a valuable resource?

Biomass is everywhere! There is a biomass component to every forest and in fact it even extends into agriculture and urban communities.

The term biomass is not well defined and often means different things to different people. In the forest community, biomass is nearly synonymous with the use of woody materials to generate electricity. However it is much more than fuel chips for combustion power plants.

I like to think of biomass as any biological plant or plant by-product that accumulates in quantities great enough to create a hazard or disposal problem or plants that are grown as an energy or feedstock crop.

Following this definition, the major sources of biomass in California include:

• Forest-based-harvesting residue--forest thinnings, dead and dying, small diameter, ill formed and other non-merchantable trees, undergrowth, and energy plantations.
• Wood Manufacturing Residue--sawmill and secondary wood manufacturing waste, including chips, solid wood scrap, and sawdust.
• Chaparral --dense thickets of shrubs and small trees in non-forested, undeveloped lands.
• Urban Lignocellulosic Wastes--removals and prunings of city trees, yard waste, woody fiber-consumer waste (lumber and wood products but not paper).
• Agricultural Residue--rice straw, cotton stalks, orchard prunings and removals, nut hulls, and similar materials (not including animal manure or food processing wastes).

The forest-based and wood manufacturing residue make up more than one-third of the approximately 36 million bone dry tons of biomass produced in California each year from the above sources (1991 California Energy Commission estimate).

Biomass is an important issue in California because excessive accumulations in forest and wildland regions may have an adverse effect on ecosystem health and often increase the fire hazard. Biomass has a direct effect on wildfire and the resultant catastrophic losses to structures, the environment, and obviously the potential loss of human life.

The California Department of Forestry & Fire Protection estimates that over 2.5 million people and 1 million structures are at risk from wildland fires in the state. It is generally recognized that past forest management practices, drought conditions, and beetle infestations have resulted in an unprecedented accumulation of biomass in many urban, wildland, and forest regions. Undoubtedly, biomass is an important component of the ecosystem and what constitutes an excessive accumulation is continually being debated. What is clear, however, is that as biomass levels increase the fire risk increases and fuel reduction efforts are warranted.

The reduction of forest-based biomass as a potential solution to many wildfire and forest health problems creates a new concern-what to do with the biomass that is removed. Traditional biomass disposal methods of burning or landfill (especially in urban areas) are facing many economic and environmental restraints that limit their use. The operating and containment costs, reduction in allowable burn days, air quality concerns, and the extremely high fuel load levels found in many regions may limit the use of prescribed burning. High landfill costs and the state-mandated diversion of 50% of materials from landfills to other uses by the year 2000 (State Assembly Bill 939), make landfill disposal an unreasonable option in most cases.

Forest-based biomass utilization is an important issue in California because it may help offset the high cost of fuel reduction. Unfortunately, as reported by the UC Forest Products Laboratory (UCFPL) in a preliminary study of the utilization potential of biomass, the options are limited for many conventional products because of the low quality material properties of much of the biomass.

From a technical point of view, combustion processes appear to be the most viable, but current economic realities limit their use. Since the early 1970s the biomass-based electricity power plants have played a vital role. At their peak, biomass and co-generation plants (those that produce both electricity and process energy for manufacturing) had a total capacity of 975 megawatts of electricity which used about 16 million tons (wet basis, not dried) of biomass per year from all sources.

As a result of negotiations involved in the deregulation of electricity (State Assembly Bill 1890), electrical power plants using biomass fuel are at a competitive disadvantage with most other electrical generation methods in the state. Also, equipment changes needed to comply with the more restrictive air quality regulations that are expected in the near future will likely add to the operating costs of these plants. As a result only a handful of biomass plants remain.

In 1998, the biomass power plant capacity is expected to be about 45% less than the 1995 levels, reducing total biomass consumption to about 8 million tons, of which about 60% will be forest-based and wood manufacturing residue. Since the biomass fuel market is one of the few options presently available for forest-based biomass, this decrease will likely have a serious impact on fuel reduction management, unless other utilization options are created.

Another possible energy production method receiving serious attention is the conversion of biomass to ethanol. A strong demand is expected for ethanol as a clean-burning gasoline additive, but very little ethanol is produced in California. In a recent feasibility study initiated by the Quincy Library Group, it was determined that an adequate supply of biomass existed within a 25 mile radius of several potential sites to support a successful 15 million gallons per year. This is about 10 percent of the current western ethanol needs in the northern Sierra of California. If refineries begin using ethanol instead of the additive MTBE in reformulated gasoline, then feasibility of a biomass-based California ethanol plant would be even more positive. Tosco, one of the California refineries, announced in April, 1998 that they were beginning to substitute ethanol in place of MTBE for gasoline in the San Francisco market.

Using forest-based biomass in other conventional products is technically feasible but unlikely because of raw material quality concerns, high manufacturing costs, and/or market conditions. For example, densified solid fuels such as pellets and briquettes are presently made from manufacturing wood waste and could be made from other biomass materials, but the over capacity of the industry and the uncertain future of the fuel pellet market make this a risky venture. Compost and mulch are often a popular solution, especially in urban areas, but the market is close to saturation. Small diameter trees could be made into conventional lumber but the manufacturing costs would be high and the lumber would be low quality.

Biomass is currently used in the pulp and paper industry, but the demand is currently being met and utilizing additional biomass in this market is unlikely. Composite wood products, such as Oriented Strand Board, Medium Density Fiberboard, Laminated Veneer Lumber, and Oriented Strand Lumber could be manufactured from some biomass materials, but it is unlikely because there is an excess capacity with existing plants using single species or clean wood manufacturing residue.

Combining wood fibers with plastic polymers, cement or other inorganic binders have the potential to use a wide variety of raw material sources, including biomass materials, but at present only pulpwood quality wood fibers are being used. These fiber/polymer and particle/cement mixtures can be molded into a variety of shapes and sizes to make a wide assortment of products. The potential of these mixtures is just beginning to be explored.

There appears to be little disagreement that large quantities of biomass exist and that the volume is increasing rapidly. The question, "is it a valuable resource" is still unanswered. Many products have the potential to use biomass-based raw materials, but with sufficient quantities of higher quality raw materials available it is unlikely that biomass will be used unless incentives for their use are available to the manufacturers. Creative approaches to biomass reduction and utilization must consider:

• Assessment of biomass availability as a raw material
• Models for communities to assess solutions for biomass fuels reduction
• Research and development of high value uses of biomass in consumer products
• Effective, low-cost biomass harvesting equipment
• Low emission incineration techniques
• Support of biomass-produced electricity
• Continued development of ethanol technology based on biomass fuel
• Studies on disposal of biomass and ash in wildlands and agricultural soils

John Shelly is a Cooperative Extension Advisor in Forest Products and Biomass, University of California Forest Products Laboratory, Richmond, CA.