Nemet Gregory F
La Follette School of Public Affairs and Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI, USA.
Environ Sci Technol. 2009 Mar 15;43(6):2173-8. doi: 10.1021/es801747c.
If photovoltaics (PV) are to contribute significantly to stabilizing the climate, they will need to be deployed on the scale of multiple terawatts. Installation of that much PV would cover substantial portions of the Earth's surface with dark-colored, sunlight-absorbing panels, reducing the Earth's albedo. How much radiative forcing would result from this change in land use? How does this amount compare to the radiative forcing avoided by substituting PV for fossil fuels? This analysis uses a series of simple equations to compare the two effects and finds that substitution dominates; the avoided radiative forcing due to substitution of PV for fossil fuels is approximately 30 times largerthan the forcing due to albedo modification. Sensitivity analysis, including discounting of future costs and benefits, identifies unfavorable yet plausible configurations in which the albedo effect substantially reduces the climatic benefits of PV. The value of PV as a climate mitigation option depends on how it is deployed, not just how much it is deployed--efficiency of PV systems and the carbon intensity of the substituted energy are particularly important
如果光伏要对稳定气候做出重大贡献，就需要以数太瓦的规模进行部署。如此大量的光伏装置将使地球表面的大片区域被深色的吸光面板覆盖，从而降低地球的反照率。这种土地利用变化会产生多大的辐射强迫？这个量与用光伏替代化石燃料所避免的辐射强迫相比如何？本分析使用一系列简单方程来比较这两种效应，发现替代效应占主导；用光伏替代化石燃料所避免的辐射强迫大约比反照率改变所产生的强迫大30倍。敏感性分析，包括对未来成本和效益的贴现，确定了一些不利但合理的配置，其中反照率效应会大幅降低光伏的气候效益。光伏作为一种气候缓解选项的价值取决于其部署方式，而不仅仅是部署量——光伏系统的效率和被替代能源的碳强度尤为重要。
