A Power Engineer View on Space Based Solar Power

The current interest in Space Based Solar Power (SBSP), surfing on the push for greener energy sources, is opening the way to an eruption of projects. One of their common claims is that, thanks to the (almost) permanent sun illumination met in Geostationary Earth Orbit (GEO), the cost per “continuous watt” would be competitive w.r.t. terrestrial solutions, like photovoltaics or windmills, when including their need for storing energy to face periods of source unavailability (night or low winds). This can be seen, at best, as overoptimistic, given the number of assumptions made in the various studies and reports, encompassing technological, development, validation, deployment, operational and financial point of views. The objective of this paper is to deliver a first order evaluation of the power management, conversion, distribution and wireless transport aspects and to show that, from this technical point of view, the feasibility of gigawatt size SBSP systems is everything but established. A brief assessment of some other aspects is also provided, going in the same direction. Altogether, the conclusion is that the analyses about the economic and environmental benefits of SBSP, sometimes extremely detailed, are built on a technical ground far from being solid enough to make them credible.