(30d) Land Availability, Utilization, and Intensification for a Solar Powered Economy

Li, Y., Purdue University
Agrawal, R., Purdue University
Among all forms of renewable energy, solar energy is the most promising one with sustainable availability and abundance to meet human being’s energy need. However, solar energy is a diffuse resource and harvesting it requires vast tracts of land. While most studies estimated that land availability is not a major challenge for the feasibility of a total solar economy, a few recent detailed analyses have raised the problem in land availability in some densely populated countries, using actual solar farm production data and considering other factors such as storage requirement and intermittency of solar availability. However, according to their estimation, countries with relatively low population density, such as the United States, have sufficient land for solar farms to meet all energy demand. In this study, we perform a detailed land requirement analysis in each state of the US for a solar powered future and propose land intensification strategies to resolve possible land use challenges.

Land requirement analysis in this study takes into account several issues that are usually ignored. First, efficiencies of major energy conversion steps from current primary energy to end use are different from those when solar energy is deployed. Second, available land is limited to only part of the urban area (rooftops) and miscellaneous land. Farmland, forest and other reserved land such as national and state parks cannot be utilized for solar plant construction. In addition, we prefer local photons for local use for consideration of minimizing transmission loss and energy security.

Our land requirement analysis shows that for many states there is insufficient currently available land and that other land areas will need to be used, which is contrary to previous report. We propose that farmland is the best choice for land use intensification as it minimizes additional environmental impact to existing habitat and propose several photovoltaic systems for this purpose. We then estimate the power output of these systems and estimate the amount of farmland for each state that is needed to meet energy needs. By land intensification, the energy demand of each state in the US can be locally satisfied.