Energy and CO2 balances in different power generation routes using wood fuel from short rotation coppice

By substituting fossil fuels and storing carbon in biomass and soil, the development of bioenergy can play a significant role in the reduction of CO2 emissions to the atmosphere. The objective of this study was to carry out an energy and carbon analysis of different power generation routes using wood fuel from short rotation coppice. Three scenarios of wood fuel production were considered, based on the level of intensification of cultivation practices, in terms of machinery and materials input. Local and regional transportation were distinguished, as well as natural convection or forced ventilation for drying. We also studied three conversion systems: local peak electricity generation, local cogeneration of heat and power (CHP), and centralised power generation by wood and coal pulverisation cofiring. The energy and carbon balances of different wood-energy routes were estimated by calculating direct and indirect energy and carbon costs of all their components (fuel, materials and machinery). Energy ratios of 22, 23 and 26 after storage and drying at the farm were obtained respectively for the different scenarios. An average of 1.7 kg of carbon (kgC) is released per GJ of wood energy produced. Crop maintenance, and chemical fertilisation, account for 40% of total energy costs and 25% of total carbon costs of wood fuel production. Final avoided carbon emissions by fossil fuel substitution reach 6.3 to 8.8 tC ha(-1) yr(-1) with CHP, 3.8 to 5.4 with peak power production and 3.3 to 4.6 with centralised cofiring. (C) 1998 Elsevier Science Ltd. All rights reserved