Synopsis
The report evaluates the potential benefits, challenges, and options for NASA engagement with growing global interest in space-based solar power (SBSP). SBSP entails collecting solar energy in space, transmitting it to Earth, converting it to electricity, and delivering it to the grid. Proponents claim SBSP could provide carbon-free renewable energy at competitive prices while accelerating space industry growth. Skeptics contend SBSP has no clear path forward and would divert resources from known solutions.
The study assesses two SBSP system designs, each normalized to 2 gigawatts capacity. The Innovative Heliostat Swarm (RD1) uses autonomous reflectors to concentrate sunlight. The Mature Planar Array (RD2) has fixed solar panels and is less complex. Lifecycle costs and emissions were estimated for development, assembly, 30 years of operations, maintenance, and disposal.
For the baseline analysis, launch and manufacturing are key drivers, comprising over 90% of lifecycle costs. Results show RD1 costs $0.61 per kilowatt-hour (kWh) and RD2 $1.59 per kWh – much higher than the $0.02 to $0.05 range for terrestrial renewables. Similarly, launch and manufacturing dominate lifecycle emissions, with intensities of 26 and 40 grams CO2 equivalent per kWh. These are comparable to nuclear and renewables, pending further study of launch effects on the upper atmosphere.
Sensitivity analyses assessed input changes like reduced launch costs and improved manufacturing. No single change makes SBSP competitive on cost, but a combination of advances could. For example, cutting launch prices in half, doubling hardware lifetimes, and learning curve improvements reduces costs to $0.03 per kWh. Further analyses of cutting-edge designs using rigorous assessments could better characterize feasibility.
Qualitative assessment reveals technological, regulatory and policy barriers. Mastering industrial-scale in-space assembly and manufacturing is a key hurdle. Power beaming, spectrum allocation, orbital debris regulation, and launch availability also pose challenges. However, opportunities exist in areas like autonomous systems, modular architectures, and advanced materials.
NASA invests in many relevant technologies for its own mission needs. The agency could maintain this focus while tracking external SBSP progress and supporting U.S. developers upon request. Alternatively, NASA could pursue expanded partnerships, given the enabling technologies’ relevance to SBSP and other applications. Recommended next steps include evaluating SBSP’s utility for NASA missions and regularly reviewing global developments.
In summary, baseline SBSP systems are not yet economically competitive with terrestrial renewables. With significant advances in multiple areas, however, SBSP could one day provide carbon-free renewable energy. NASA develops related technologies for its missions and could enhance coordination and assessments regarding SBSP.
