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Solar energy, though promising as the energy source for a fossil fuel-deprived future, is a dilute resource and harvesting it requires vast tracts of land. In this study, we develop an extensive process system model for land requirement analysis in each of the 48 contiguous states of the United States for a solar powered economy to address the likely land competition. Land requirement analysis in this study takes into account several issues that are usually ignored. Efficiencies of major energy conversion steps from primary energy to end use are accounted and intermittent solar availability, actual solar farm output and land availability are all considered. In addition, we prefer local photons for local use for consideration of minimizing transmission loss and energy security. Under this preferred scenario, our land requirement analysis shows that 16 of the 48 contiguous states have insufficient available land and that the land competition for energy and food will be intense. Thus, in a solar economy, land use intensification will be required to avoid conflict between our competing land use needs. 

The recent shale gas boom has transformed the energy landscape of the United States. Compared to natural gas, shale resources contain a substantial amount of condensate and natural gas liquids (NGLs). Many shale basin regions located in remote areas are lacking the infrastructure to distribute the extracted NGLs to other regions—particularly the Gulf Coast, a major gas processing region. Here we present a shale gas transformation process that converts NGLs in shale resources into liquid hydrocarbons, which are easier to transport from these remote basins than NGL or its constituents. This process involves catalytic dehydrogenation followed by catalytic oligomerization. Thermodynamic process analysis shows that this process has the potential to be more energy efficient than existing NGL-to-liquid fuel (NTL) technologies. In addition, our estimated payback period for this process is within the average lifetime of shale gas wells. The proposed process holds the promise to be an energy efficient and economically attractive step to valorize condensate in remote shale basins.