Space Solar is more cost effective than Terrestrial Solar

One reaction to space-based solar power (SBSP) is that it will always have a substantial cost gap compared to Earth-based solar power. However, the economics of SBSP have changed. They have changed a lot and will continue getting better.

One of the mains reasons for the resurgence in interest is the recent drop in launch costs. When #SBSP was first studied in depth in the 1980's, the cost of launch was more than $65,000/kg [1]. With Falcon heavy the cost is now less than $1400/kg [2] and expected to drop further. But that is not the whole story.

Since 1980, when NASA - National Aeronautics and Space Administration sponsored the first studies on SBSP, the best solar cells have improved from about 16% efficiency to almost 48% efficiency today. [3] By incorporating these improvements, SBSP can be realized with only 10% of the mass envisioned back then. Using data from ESA SOLARIS and Roland Berger [4], the improvements in SBSP power density can be clearly seen in the plot below.

But there is more! During the same time period, solar decreased in cost more than 99% [5]. That is a two order of magnitude decrease in cost.

When combining the decrease in launch costs, and the improvement in satellite power density, and the decline in the costs of solar, the economics of SBSP have improved by 4 to 5 orders of magnitude since it was first seriously considered. This is why it is now cost competitive and the trends show it can continue improving.


[1] https://aerospace.csis.org/data/space-launch-to-low-earth-orbit-how-much-does-it-cost/
[2] https://en.wikipedia.org/wiki/Space_launch_market_competition
[3] https://www.nrel.gov/pv/cell-efficiency.html
[4] https://www.esa.int/Enabling_Support/Space_Engineering_Technology/SOLARIS/Cost_vs._benefits_studies
[5] https://en.wikipedia.org/wiki/Swanson%27s_law