In a scientific first, researchers from Caltech beamed power generated in outer space back to Earth. The Space Solar Power Demonstrator proves the scientific basis for a new, long-hoped for energy source: space-based solar power (SBSP). By capturing solar energy in outer space, without the many factors that make terrestrial solar intermittent, SBSP can unlock a whole new class of baseload energy technologies to provide clean energy and reduce carbon emissions. The rapid reduction in launch costs enabled by the growing commercial space sector means that it could be economic within the next couple of decades. Among other entities, the European Space Agency, China, Japan, and the U.S. Department of Defense are all actively pursuing research and development in this area. However, Caltech’s achievement is overshadowed by an uncomfortable fact: despite being the world’s leader in space activities, the United States is in danger of falling behind on SBSP and may lose this emerging sector to geopolitical competitors. In short, the United States needs a comprehensive strategy to develop and commercialize space-based solar power by combining the public and private sectors to solve complex engineering, economic, and regulatory challenges.
After a relatively stable decade in energy markets, major global changes are underscoring the dependence of modern economies on energy services. Pandemic-driven disruptions in energy markets, including an accelerated oil boom and bust, undermined near-term investment in energy supply. Russia’s invasion of Ukraine has further exacerbated energy price volatility, raising the prospect of Europe losing its larger supplier of energy and the world losing its second-largest oil supplier. More broadly, the reemergence of global geopolitical competition, particularly between the United States and China, is leading to escalating competition over strategic industries, including energy and space. Finally, all of this is occurring against the backdrop of ever-worsening climate change and the ever-pressing need to reduce carbon emissions as much as possible as fast as possible. Even with the growth of wind and solar, and the emergence of other advanced energy technologies, the world needs all of the clean energy it can get. Further, as legacy thermal powerplants are retired at an increasing rate, the need for dispatchable and baseload power systems is becoming ever more acute.
Space-based solar power speaks to all of these needs in one package: it can be dispatched quickly to support system ramping, it can provide baseload power at very high capacity factors, it produces zero direct emissions, it is resilient, and it can achieve all of this simultaneously. The scientific first principles are simple. Solar power in space is about eight times more powerful than on the Earth’s surface because it does not need to go through the atmosphere, it is not blocked by clouds, and does not experience nighttime. If this solar power could be collected and beamed back to Earth, namely with long wavelength microwaves, terrestrial markets could gain access to a 24/7 clean energy source. Of course, the complexity of such an undertaking is not trivial. SBSP was first popularized by astrophysicist Gerard O’Neill in the 1970s, but progress has only occurred in fits and starts, in large part because costs remained prohibitive.
With the rise of commercial space innovators like SpaceX, the economic equation for SBSP is starting to flip. Reusable rocketry, off-the-shelf satellite equipment, and economies of scale are driving down the costs of space access. Additional innovations like commercial space stations and in-space assembling and manufacturing can support the construction of large, complex satellite installations. The potential for space mined resources from the Moon and asteroids can further reduce material costs.
Many regions, especially those facing desperate energy situations, are starting to notice. The European Space Agency (ESA) is embarking on the ambitious Cassiopeia program to develop SBSP. Underlying this program are two studies by ESA finding that the first utility-scale demonstration project could cost less than $20 billion. While costly, such a price tag is on par with many first-of-a-kind energy megaprojects, such as the construction of two new nuclear reactors in Georgia. China sees SBSP as a way to become an energy and space superpower. It has plans for a low Earth orbit test in 2028 and a geosynchronous orbit test in 2030.
In the next several decades, the world could effectively build hundreds of gigawatts of baseload, utility-scale power plants, anywhere in the world. Certain configurations could enable SBSP stations to switch between power markets, enhancing system reliability and flexibly complementing variable renewable energy sources. Countries that have not been blessed with the economic advantages of energy resources could not only produce their own domestic energy securely, they could develop export markets by sending excess space power production to world markets. Beyond grid-scale power, SBSP can support many types of advanced energy activities, from remote defense operations to orbital satellites, to bases on the surface of the Moon or Mars. And all of this with limited carbon emissions—although space stations require rocket launches, the lifecycle emissions are likely to be comparable to other clean energy sources.
However, the United States is not currently on track to join in this energy abundance. Only a handful of American entities are working on SBSP, namely the Department of Defense and Caltech. NASA is funding several projects focused on power beaming, but only for space applications. No R&D nor commercialization roadmap exists for U.S. agencies and the private sector. Without broader coordination and a demand driver, there will simply be insufficient investment to support the development of utility-scale SBSP.
A broader American innovation ecosystem has yet to develop. Notably absent from these developments are some of the most important entities for developing commercialized energy technologies: the Department of Energy, national laboratories, and power sector customers. Space industry efforts alone cannot unlock this technology. Further, important policy and regulatory venues for such space energy systems, like the State Department, Federal Energy Regulatory Commission, and Federal Communications Commission, have yet to establish a sufficient legal foundation.
What would a comprehensive strategy look like? Early this year, we published an article in the journal Space Policy arguing that a technology development program can form the keystone of such a strategy. We proposed the use of a public-private partnership to progressively de-risk the technology while lowering prices. Starting from small-scale activities, an aggressive but feasible program could reach utility-scale, cost-competitive systems by the 2040s. The Department of Energy’s new Office of Clean Energy Demonstration, created in the recent infrastructure bill, would be a perfect host for such a program.
Beyond technology demonstration and cost reduction, such a program would also enable sustained policy development to establish a long-term regulatory framework. Regulatory challenges include the use of radio spectrum currently used by other satellites and terrestrial users, addressing concerns about the security and safety of microwave beaming, and the integration of SBSP into highly regulated energy markets.
The most important starting step is for the Biden administration and Congress to declare the development of space-based solar power a national priority to fight climate change, enhance energy security, and secure global competitiveness in two strategic sectors. Interagency coordination across NASA, the Department of Defense, and the Department of Energy can direct government investment to enabling technologies in the laboratory. Private-sector-led innovation, working closely with academia, can take these innovations into actual deployment, reducing costs through staged deployment.
Ultimately, SBSP could become one of the defining energy sources of the twenty-first century. By complementing other clean energy sources like wind, solar, and nuclear power, it can secure global mid-century decarbonization while ensuring the United States and its allies protect their energy security. And even if long-shot carbon-free technologies like nuclear fusion were to become commercially viable, SBSP’s unique characteristics would still justify the investment into it. As fantastical as it sounds, solar power beamed from space is exactly the kind of leadership-defining, world-changing bets that the United States should be making this century.
Alex Gilbert is a Fellow and Ph.D. student at the Colorado School of Mines, and Director of Space and Planetary Regulation at Zeno Power.
Leet W. Wood currently works in energy policy and regulation at a DC not-for-profit. He received his doctorate from George Mason University in 2019.