Analysis of life cycle thermo-ecological cost of electricity from wind and its application for future incentive mechanism

In this paper, we apply a life cycle thermoecological cost (LC-TEC) approach to evaluate the environmental performance of wind turbines with different capacities and performance characteristics. LC-TEC expresses the cumulative consumption of non-renewable exergy burdening the fabrication of the considered consumption of the product with the additional inclusion of necessity of compensating adverse environmental effects due to harmful waste products rejection. Differently, from what has been recently done in the literature on the environmental performance of wind turbines, where the attention has been mainly drawn by analysis of single turbine, we focus on the synthesis of the results for wind turbines with different capacities and the generalisation of the results under different environmental conditions. The selected functional unit for the comparison was 1 MJ of produced electricity, assuming a service lifetime equal to 20 years. Concerning the contribution analysis, the construction phase is the most intensive one for wind energy technologies with a share varying from 64 to 77% in the overall effect. Substantial differences in LC-TEC are observed for wind turbines of different capacity and different locations of the power plant. Results show that the LC-TEC of electricity significantly decrease while the turbine nominal power increases. For instance, for the average site, described by Weibull distribution parameters of mean wind speed of 5 m/s and shape coefficient 2, the TEC-LC for 1 kW micro wind turbine is estimated to be equal to 0.436 MJ(ex) /MJ, while for a larger, 2 MW one, fall in the range of 0.053-0.063 MJ(ex)/MJ. We found that a power function can successfully describe such a trend. Moreover, we observed considerable changes in the final results for different Weibull distribution parameters. Specifically, the LC-TEC differs significantly for the sites with lower mean wind speed and different shape factors. Finally, we propose the supporting system for wind energy basing on the LC-TEC and pro-ecological taxing. According to this concept, the power units with LC-TEC below unity are to be supported, and the proposed level of pro-ecological support (ExTAX - Exergy TAX) is proportional to the thermo-ecological cost. The obtained results of exergy supporting for wind energy technologies are applied in the Italian electricity market and compared with the existing financing system for wind energy based on green certificates and feed-in tariff system.