In the quest to reach net-zero greenhouse gas emissions, there will never be just one solution. Every region must strive for a complex, adequately hedged energy mix to satisfy the rising demand globally for power while also moving toward net zero. Nowhere learned that energy security lesson more forcefully than Europe after the Russian invasion of Ukraine, but the need to reach net zero means all regions are in store for some of the same.
So far, wind and solar power have not been able to supply the continuous and flexible baseload of energy necessary because of the intermittency of both renewables. That has prompted efforts to create large-capacity battery storage that can take the generated excess and literally save it for a rainy, windless day. It has also meant reviving nuclear power as an energy option.
These solutions all present challenges. Nuclear power, for instance, still raises concerns with citizens, especially regarding the transportation, storage, and disposal of radioactive waste. And while prices are decreasing for solar and wind power, storage solutions still suffer from high investment costs, complex duty-cycles, and considerable energy conversion losses. There are also technological barriers to overcome, such as the limited gigawatt (GW) scalability of today’s batteries, confining their use to small and midsize enterprises.
Recent technological developments in space-based solar power (SBSP) make it worth considering as a viable addition to the long-term global energy mix. The governments of Japan, China, the United States, and Europe have made some initial investments, but private investor interest could speed up the development and adoption of this potentially cost-competitive and certainly sustainable technology.
How the technology works
Solar panels placed in orbit can collect sunlight 24 hours a day, seven days a week with no interference from the atmosphere. That energy can then be beamed to Earth via high-frequency radio waves, which are then captured by rectifying antennae and converted into electricity to be fed into the grid.
Several designs are being considered for the space segment, but the most promising option appears to be CASSIOPeiA, an orbiting power station weighing 2,000-plus tons that would be placed in a geostationary orbit about 36,000 kilometers from Earth. This solution would provide up to two GWs of power and require a capital investment of between €6 billion and €9 billion per individual system — an amount expected to fall as the technology is developed at commercial scale.
The design for the CASSIOPeiA station involves a helix-shaped structure housing photovoltaic panels. At either end of the structure would be two massive, fixed mirrors that are each 1.7 kilometers in diameter. These mirrors would always be orientated to face the sun.
This latest design is smaller in mass than previous concepts and provides more modularity. The entire architecture would be robotically assembled in space combining five types of standardized modules. This allows for easy replacement in case of damage to individual components, and it fosters economies of scale within the manufacturing process.
Potential timetable and advantages
Based on current technologies, the space-based approach to solar power is expected to be proved in the next 10 years and start supplying a portion of global energy consumption by 2050. Within a quarter-century, SBSP could become an integral part of the kind of sustainable mix of technologies and fuels that ultimately must satisfy future global power needs.
While the initial capital expenditures for SBSP technology can be high, the energy eventually provided is set to be cheaper per unit than the energy produced by nuclear and current solar storage solutions. Beyond that, the SBSP technology offers greater dispatchability, meaning the energy produced could be sent via antennae to the location it is most needed.
Compared specifically with nuclear power, space-based solar power also can operate for more hours during a year — 8,680 hours per year versus 8,000 for a nuclear plant. It also poses no radioactive waste potential.
Above all, space-based solar power is a low-carbon source of energy. Even considering the space launches required to build the in-orbit architecture, which represent the largest component of emissions from space-based solar power, the total carbon dioxide emitted throughout the 30-year lifecycle amounts to only 100,000 to 200,000 tons per year.
Space’s potential impact and challenges
The development of space-based solar power could have a large impact not only on the critical energy sector and emissions but also on the global economy from the technological boost it would provide to the manufacturing sector.
The substantial investments in research and development in such areas as robotics, wireless power transmission, and reusable space launchers required to achieve SBSP will generate knowledge that will also foster innovation across all connected industries. Unquestionably, such large-scale investment would create unprecedented growth opportunities for private companies within the space market, with launch system manufacturers and satellite manufacturers, operators, and integrators among the primary recipients.
Despite undeniable potential advantages, the development of the required technologies is still in its early stages and will have significant challenges to overcome. A few of those challenges include the reduction of solar panel costs, wireless power transmission, in-orbit assembly and decommission.
Launch vehicles reusability
One of the biggest obstacles to powering forward is the need for a dramatic reduction of launch costs and developing vehicles that will be reusable. Establishing launch vehicle reusability would significantly lower the overall investment required to build a SBSP system.
Currently, space launch costs to geostationary orbit are estimated at between €3.5 million and €7.5 million per ton and account for 46% of the total required CAPEX funding. Strategic planning would need to be in place to ensure the best slots become available to maximize efficiency of SBSP. But this cost could be drastically reduced if SpaceX is able to achieve spending goals and accelerated timetable for its launch vehicle program.
Based on current SpaceX launch technology, for example, assembling the full SBSP structure would require 94 Falcon Heavy launches or 119 Starship launches (based on mass calculations of the parts being transported) which could test global launch capacity. Additionally, the in-orbit assembly of such a massive module — expected to be six times larger in mass than the International Space Station — poses engineering and assembly challenges, given the limited experience of the workforce with such advanced robotics.
Potential market and leaders
Assuming it is developed over the next 10 years, SBSP technology has the potential to reach 700 terawatt hours (TWh) of energy production in 2050. For the European Union, for instance, that would represent 15% of anticipated electricity consumption that year.
Focusing on the potential impact on the European industrial landscape, should SBSP reach that level by 2050, there would be significant contributions to various sectors that would be worth:
- Between €160 billion and €260 billion for building
- Between €170 billion and €260 billion for launching
- Between €10 billion and €30 billion for R&D
- Between €260 billion and €290 billion for operation between connection, maintenance, and insurance of the space, ground, and communication systems, over an operating life of approximately 30 years
- €140 billion per year in energy production
Attracted by the potential advantages of this innovative solution, multiple countries have started investigating and testing SBSP-related technologies. China and Japan have taken the lead, announcing their first prototypes to be ready by 2028. The United States is also developing the required technological capabilities. The United Kingdom has integrated it into its national space strategy.
The European Space Agency has also started investigating the opportunity by commissioning two feasibility studies. The results of both have so far looked encouraging, but the agency needs to deploy a prototype soon if it wants to stay in the game.
But there are some limits on capacity, with a maximum of 1,800 slots available for geostationary orbit to ensure adequate distance between spacecraft. Of those slots, the locations in most demand are over high-population density areas. These would be ideal for the SBSP technology, but they would also be the type of slots that telecommunications satellites would seek.
Countdown to investment
As with all new technologies, there are development risks associated with space-based solar power: high R&D cost and extended timeline, the challenge of in-orbit assembly, operating technologies developed for Earth in a geostationary orbit, and extensive launch capacity requirements.
But the opportunity has its merits: Solar power would be a cheap and continuously available source of completely decarbonized energy. This potential multibillion-dollar market is likely to attract investment from a variety of industrial players — including aerospace companies with one foot already in space, energy and power companies looking to expand their green energy portfolio, and electronics corporations with Earth technologies they could upgrade to work in orbit. Eventually, launcher manufacturers would see their market mature and multiply quickly, opening the door for more economies of scale, improved reusability, and lower costs.
While public funding can finance initial studies and concepts, we believe that the fastest and most cost effective way to develop this technology would be through a multi-industry consortium of players, all interested in sharing risks and rewards and with a clear mission to develop clean energy for our planet.
First-mover advantage exists, given that in-orbit slots are limited. Which consortium will make it into orbit first?