TY - RPRT
TI - Replacement of Old Wind Turbines Assessed from Energy, Environmental and Economic Perspectives
AU - Rydh, C
AU - Jonsson, M
AU - Lindahl, P
AB - Different operating conditions and alternatives for treatment and replacement of old 225 kW windturbines (WTs) were evaluated from a life cycle perspective from cradle to grave. Indicators werecalculated for primary fossil energy requirements (MJpf/kWhel), CO2 emission (CO2/kWhel) andeconomy (€2004/kWhel).Extending the service life ten years by renovation results in 32% lower primary energy requirementsthan if the WT is recycled after 20 years at the end of the technical service life. The primary fossilenergy requirement for electricity production is 2.5 - 4.6 times higher for fossil based electricityproduction than for WTs. The energy payback time was calculated to 3.9 months for 225 kW WTs andto 2.7 months for 2 MW WTs. This means that after 3.9 months electricity production, the WT startsto generate net electricity.The CO2 emission for WTs was calculated to 7.2-11 g CO2/kWh, which is 4.6 lower than the averageSwedish electricity mix and 122 times lower than for a coal condensing plant. The highest CO2emission for electricity generation from WTs was found in the phase of materials production (60-64%of the total emission) followed by production of WTs (32%). The phases of transportation/disassemblyand renovation/maintenance have relatively low influence, contributing 2-3% and 2-6%.The monetary costs for electricity production were calculated to be in the range 2.9-5.4 € cents/kWh(excluding VAT and subsidies). The lowest cost was found for 2 MW WTs and the highest cost forrenovation of 225 kW WTs.The relative importance of different parameters influence on energy requirements and CO2 emissionswere found to be as follows: (1) service life, wind conditions/conversion efficiency and materialrequirement, (2) recycling rate and, (3) transportation distance.To utilise areas suitable for wind turbines efficiently, it is important to use the most efficienttechnologies with highest possible electricity yield. A comparison of the indicators for the differentcases shows that they are pointing in different directions, which makes it possible to optimise WTs indifferent ways depending on subjective values. Physical flows of energy, materials and CO2 emissiondecrease per unit produced electricity when the service life is extended by renovation. On the contrary,when the considering a monetary perspective, the costs increase when extending the service life byrenovation since labour costs is highly valued.The Excel computer model developed in this project can be easily updated in order to evaluatetechnological development and different operating conditions of WTs.
DA - 2004/06//
PY - 2004
SP - 33
PB - University of Kalmar
SN - SE-391 82 Kalmar
LA - English
KW - Wind Energy
KW - Land-Based Wind
KW - Human Dimensions
KW - Life Cycle Assessment
ER -