Public and private electric utilities are considering co-firing biomass with coal as a strategy to reduce the levels of CO2, SO2 and NOx in stack emissions, as well as a response to state legislative mandates requiring the use of renewable fuels. This analysis examines the conditions under which biomass co-firing is economically feasible for utilities and woody biomass producers and describes additional environmental and community benefits associated with biomass use. This paper presents a case study of woody biomass production and co-firing at the Northern Indiana Public Service Company (NIPSCO) Michigan City Unit No. 12 power plant. A Salix (willow) production budget was created to assess the feasibility of plantation tree production to supply biomass to the utility for fuel blending. A GAMS model was developed to examine the optimal co-firing blend of coal and biomass while minimizing variable cost, including the cost of ash disposal and material procurement costs. The model is constrained by the levels of pollution produced. This model is used to examine situations where coal is the primary fuel and waste wood, willow trees, or both are available for fuel blending. Capital costs for co-firing were estimated outside of the model and are incorporated into the total cost of co-firing. The results indicate that under certain circumstances it is cost-effective for the power plant to co-fire biomass. Sensitivity analysis is used to test biomass price sensitivity and explores the effects of potential public policies on co-firing.

Economic surveys of fisheries are undertaken in several countries as a means of assessing the economic performance of their fisheries. The level of economic profits accruing in the fishery can be estimated from the average economic profits of the boats surveyed. Economic profits consist of two components—resource rent and intra-marginal rent. From a fisheries management perspective, the key indicator of performance is the level of resource rent being generated in the fishery. Consequently, these different components need to be separated out. In this paper, a means of separating out the rent components is identified for a heterogeneous fishery. This is applied to the multi-purpose fleet operating in the English Channel. The paper demonstrates that failing to separate out these two components may result in a misrepresentation of the economic performance of the fishery.