Evolution and feasibility of decentralized concentrating solar thermal power systems for modern energy access in rural areas

The desire of the international community to balance global economic growth against concerns of accelerated CO 2 emissions has brought solar technologies into the forefront for meeting increasing energy demands. This manuscript discusses the historical and potential future roles for small-to-medium scale solar thermal technologies in addressing the challenge of leveling energy access standards across countries with widely variable economic resources and consumer needs. Access to modern energy services, such as heating for water, pumping for agricultural irrigation or potable water sources, and an on-demand 24/7 electrical grid, is central to provision of high quality social services, economic growth, and improved quality of life; however, over 1 billion people remain unelectrified globally. Enabling the projected growth in energy demands without relying on fossil fuels requires consideration of the viability of renewable energy technologies to serve these markets; this manuscript provides a discussion of the role of solar thermal energy systems in this capacity. A survey of systems under 1 MW capacity reported in the literature (academic and commercial) was conducted, with projects aggregated by service type (heat, cooling, electricity, or multi-) in the database provided as an appendix to this manuscript. In general, many hardware configurations have been explored, with economics driven substantially by supply chain pricing, and no clear winner has emerged. Process heat applications demonstrate economic competitiveness over a wide range of commercial applications; however, early explorations into power generation—or co/tri-generation configurations—provide indications that such technologies, while not expected to reach grid-parity tariffs, may in fact provide the most economical pathway to energy delivery in the currently most underserved communities.