Environmental sustainability assessment of a wind battery

Fig. 6. Allowable annual ozone-depleting substance (ODS) emissions (excluding nitrous oxide) per capita with respect to the percent loss in stratospheric Lithocholic Acid over the time scale for considering sustainability.Figure optionsDownload full-size imageDownload as PowerPoint slide
Absent from most life-cycle analyses that include ozone-depleting substances is the effect of N2O on stratospheric ozone depletion. Although the ozone depletion potential of N2O is modest (i.e., 0.017), it is an unregulated substance with substantial global emissions (Ravishankara et al., 2009). Incorporating N2O into the analysis significantly alters the results (Fig. 7).
Fig. 7. Allowable annual ozone-depleting substance (ODS) emissions (including nitrous oxide) per capita with respect to the percent loss in stratospheric ozone over the time scale for considering sustainability.Figure optionsDownload full-size imageDownload as PowerPoint slide
The allowable emissions curve does not change by including N2O as an ozone-depleting substance but the horizontal gas-fired power plant and wind-battery system lines shift up. Emissions from a wind-battery system now correspond to 2.3% stratospheric ozone depletion over 50 years up from 0.2% in Fig. 6. Although depletion is an order of magnitude higher than when excluding N2O emissions the overall reduction is manageable. However, ozone-depleting substance emissions from the gas-fired power plant significantly increase when considering N2O, which is a by-product of combustion. The eventual intersection of the allowable emissions curve and the natural gas line occurs at 10% stratospheric ozone loss, which is more than two orders of magnitude higher than in Fig. 6.