Other relevant reports: 95030, 95099, 96126, 97010
Interest in biomass electricity in Ireland is being re-awakened by environmental concerns about CO2 emissions from power generation and the potential of biomass production to provide an alternative agricultural enterprise. The technical and economic feasibility of wood-fuelled power production using willow from energy farming in existing peat-fired plants in Ireland is being studied within the framework of the EU JOULE II+ programme.
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 in the form of a low and high cost estimation. All assessments were based on technology which is currently available or is expected to be available in the near future. Neither agricultural subsidies nor possible CO2 taxes have been included.
In the least cost supply scenario storage and chipping of wood is done at the power station. Wood will only be stored in the form of sticks. Chips harvesting is assumed to be done for that amount of wood that can be processed directly during the harvesting season. For the case studies in the present project the locations of Lanesborough and Ferbane were considered. The kWh costs calculated for the different power plant options that were considered can be seen in the following figure.
Figure . kWh costs of the different power plant options
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. Although it is not competing with present least cost fossil fuel prices, prices near present peat supply prices (which are expected to decrease in the near future) are possible. Improvements in biomass energy system performance can still be expected in the future.
For a smooth introduction of short rotation coppice forestry in Ireland a flexible test programme is needed in which fuel supply risks are avoided. Cofiring of willow in existing retrofitted peat plants or in peat plants to be built in the near future are very suitable for this.