Impacts of Stratospheric Aerosol Injection on Renewable Energy Systems

Abstract

Climate change is one of the 21st centurys major challenges. However, the progress in reducing greenhouse gas emissions is perceived as being too slow. Hence, more radical technologies such as stratospheric aerosol injection are entering discussions to limit climate change. This study presents a methodology for evaluating the effects of injecting 20Mt of SO$_2$ into the atmosphere annually on the global radiative balance, photovoltaic potentials, and renewable energy systems under a targeted temperature reduction of 2°C. Results show that the average annual reduction of PV potentials ranges from 0.25% to 4% up to 12% in Northern Europe during summer. The modeled renewable energy systems largely absorb these reductions resulting in minor capacity shifts with larger changes confined to a few systems. The results show that the inherent flexibility of large scale renewable energy systems helps mitigating changes in cost, but understanding this flexibility is crucial to avoid errors in design.

Figures (6)

• Figure 1: The reduction in direct irradiance is shown annually as well as seasonally after simulated injection of 20Mt of SO$_2$ in December annually for ten consecutive years to reach an equilibrium state between injection, distribution and sedimentation. Panel (a) shows the annual average reduction in direct irradiance ($\Delta$DIR), ranging from 0.8$\frac{W}{m^2}$ in the tropics to 3.1$\frac{W}{m^2}$ starting around 50°S and 50°N. Around 20°S and 20°N an increased reduction of 2$\frac{W}{m^2}$ arises from a weak tropical to subtropical exchange. Panels (b–e) show the seasonal mean changes in the same scenario. Reduction is high in the northern and southern hemisphere during the respective summer reaching up to 10$\frac{W}{m^2}$. In the tropics the reduction is strongest directly in the month after injection in December with around 4$\frac{W}{m^2}$ as shown in Panel (b). In the month from March to May shown in Panel (c) the reduction weakens and the belts around 20°S and 20°N form. In the remaining month from June to November the reduction in the tropics is negligible. The reduction starting around 20°S and 20°N is between 0.3$\frac{W}{m^2}$ and 7.8$\frac{W}{m^2}$ strongest during the summer in the month from June to November.
• Figure 2: The relative difference in PV capacity factors is shown annually as well as seasonally equivalently to the reduction in direct irradiance in Figure \ref{['fig:Delta_dir_maps']}. Panel (a) shows the relative annual average relative difference in PV capacity factors, ranging from 0.25% in the tropics to 4% Northern Europe. Panels (b–e) show the seasonal relative difference in the same scenario. Reduction is high in the northern hemisphere during the summer reaching up to 12% in Northern Europe. In the tropics the relative difference reaches up to 2% in the month after injection shown in Panel (b). In the month from March to May shown in Panel (c) the relative difference in the tropics weakens and instead spreads out to the subtropics. In the month from June to November the relative difference in the tropics reduces further and is negligible in the month from September to November. The relative difference in Northern America, Northern Europe and Northern Asia is similar throughout the year besides the summer, where it reaches up to 12%.
• Figure 3: Division of the world into a grid structure. The 16 latitude belts are divided into 16 latitude regions, giving a total of 256 sections. The numbering of the latitudes begins at the Greenwich meridian, the meridian of longitude zero.
• Figure 4: The exchange process used in this work is depicted as described by Gao et al. gao_volcanic_2008. Loop arrows indicate the exchange between two belts in the same region. Arrows between blocks indicate the exchange between neighboring belts that are not in the same region.
• Figure 5: Adapted workflow to determine the PV potential in RESKit by applying the change rate in step three.