In light of potential regulatory limits on greenhouse-gas (GHG) emissions, mandates for renewable-energy use in emerging legislation, and potentially higher prices for some conventional fossil fuels, biomass could become an increasingly important source of fuel for generating electricity and heat and for manufacturing liquid fuels. Biomass energy resources are organic matter, typically trees or plants, grown and harvested for the purpose of producing energy. Examples of biomass resources include the uncollected tops and branches from forestry operations, agricultural residues, and crops specifically grown for the purpose of producing energy, such as switchgrass. In general, because plants convert carbon dioxide (CO₂)...

To gain an understanding of the most-immediate challenges faced by plants that will use biomass for electricity generation in the near term, we spoke with the designers and operators of facilities using or planning to use biomass. As biomass use for energy increases, facility staff members are learning what is required to make these plants operational, technically and economically, both from personal experience and from the experiences of their predecessors. Companies with successful experience cofiring at one site often apply their experience to the design and implementation of cofiring at additional sites. In addition to talking with current plant operators,...

This chapter derives plant-site costs of cofiring, using a model that the research team developed (Appendix B), and provides estimates of the potential costs of cofiring biomass with coal at the plant site. Cost estimates include capital expenses for biomass handling and processing equipment and plant modifications, in addition to the cost of receiving, handling, processing, and firing biomass. We also provide estimates of net changes in GHG emissions from replacing coal with biomass. This part of the analysis incorporates estimates from the CUBE model (Curtright et al., 2010) for the life-cycle GHG emissions of the cofired biomass, which are...

This chapter describes current biomass use and estimates the potential near-term demand for biomass. The method employed begins by compiling current demand for biomass energy resources and coal use for generating electricity at the state level. Currently, biomass use for electricity in the industrial, electric power, commercial, and residential sectors comprises 1.3 percent of total generation, but, because a large share of biomass is used for industrial energy, biomass use in the electric power sector comprises only about 0.6 percent of generation. Parametrically, we increase the amount of biomass used to produce electricity to 1 percent, 2 percent, and 5...

This chapter examines the costs of handling, transporting, storing, and processing biomass from the farm gate to the energy facility. It characterizes the costs, employing three principal scenarios for supplying biomass to an energy facility: (1) biomass supplied from the local region (the current scenario for plant operators we interviewed), (2) biomass supplied from the local region and from a more distant region by long-haul transport, and (3) all biomass supplied from a distant region by long-haul transport. Each scenario considers several variants. The analysis quantifies the cost and GHG trade-offs among the alternative processing and transportation options. The methodology...

At the time of the initial DOE biomass cofiring demonstration program in the 1990s, the primary motivation for cofiring biomass with coal at electricity generating plants was to reduce criteria pollutant emissions (Tillman, 2001). Widespread switching to lower-sulfur coals, as well as the installation of pollution controls, has obviated the initial motivation for cofiring. Currently, the primary motivation for cofiring biomass with coal at electricity generating plants is to reduce GHG emissions.

In light of this objective, in this chapter, we estimate the potential reductions in GHG emissions that would result from cofiring with biomass at 5 percent by input...

Existing markets for biomass as fuel are small and regionally specific, largely because biomass is a marginal fuel compared with coal. Biomass production varies across and within regions, with small clusters of grass-based production in the Midwest, forestry residues collected in the Northeast and Southeast, and some woody biomass cultivation in the West and Northeast. Mill residues available for fuel use are concentrated in the southern and southeastern states; residue use for off-site energy production, approximately 37 million tons in 2007, constitutes roughly half the total mill residue production (ORNL, 2010). Pelletized biomass, whether wood based or using other feedstocks,...

Plant operators reported that cofiring with biomass at up to 10 percent of total fuel energy had little effect on the performance of the boiler or on installed emission-control equipment. The lower energy content and increased moisture content of biomass relative to coal can result in a reduction in plant generating capacity, but plant operators did not cite this as a significant concern. These results are consistent with reported experience in Europe (Van Loo and Koppejan, 2008) and the United States (Tillman, 2001; Antares Group, 2009). However, most domestic experience to date concerning cofiring biomass with coal is recent, consisting...