Willow firing in retrofitted Irish peat plants: Background report 4.3 for the EU Joule 2+ project: Energy from biomass: An assessment of two promising systems for energy production

The technical and economic feasibility of wood-fuelled power production using willow in existing peat-fired plants in Ireland is studied. Different background studies supplied data for yields of willow farming, establishment of willow plantations, harvesting methods, logistics and costs and efficiencies for different retrofit options at Irish peat plants. Input data in the calculation have been presented in ranges which leads to kWh costs. All assessments were based on technology which is currently available or is expected to be available in the near future. In the least cost supply scenario storage and chipping of wood is done at the power station. For the case studies in the present project the locations of Lanesborough and Ferbane were considered. The differences between the high and low kWh costs estimation appeared to be very large. The cheapest proven retrofit option is the conversion of the existing milled peat Lanesborough unit 3 into a bubbling fluidized bed. For this plant costs per tonne of avoided CO2 emissions varied between 1 and 70 ECU. Especially for the retrofitted plants the fuel costs are by far the largest cost component, resulting from their relatively low efficiencies. A biomass integrated combined cycle system (BIG/CC) appeared to have lower kWh cost than all biomass combustion plants, especially in the high costs estimation. All technologies considered have the possibility of cofiring peat and biomass. From the sensitivity analysis it becomes clear that the yields (ranging from 8 to 11 tonnedb/ha.yr) and the annual income for land to farmers (ranging from 150 to 600 ECU/ha.yr) are the dominating factors in the kWh costs. It is notable that raising the average transport distance with 100 % (up to 80 kilometres), only raises the kWh price with less than 2 %. Biomass firing in Irish peat plants is a promising option for Ireland to generate CO2 neutral electricity. (Abstract Truncated)