In light of potential regulatory limits on greenhouse-gas (GHG) emissions, requirements for greater use of renewable fuels, and higher prices for some conventional fossil resources, over the course of the next few decades, biomass is expected to become an increasingly important source of electricity, heat, and liquid fuel. One near-term option for using biomass to generate electricity is to cofire biomass in coal-fired electricity plants. Doing so allows such plants to reduce GHG emissions and, in appropriate regulatory environments, to generate renewable-energy credits to recover costs. This report focuses on two aspects of biomass use: plant-site modifications, changes in operations, and costs associated with cofiring biomass; and the logistical issues associated with delivering biomass to the plant. The authors find that the main challenge is maintaining a consistent fuel supply; technical and regulatory factors can drive the decision to cofire; cofiring can increase costs, decrease revenue, and reduce GHG emissions; densification does not reduce plant costs but can reduce transportation costs, however current markets cannot support use of densified fuels.