This article was originally published at The conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.
Jovana RadulovicHead of the School of Mechanical and Design Engineering, University of Portsmouth
The UK government is reportedly considering a £16 billion proposal to build a solar power plant in space.
Yes, you read it right. Space-based solar power is one of the technologies that will be included in the government’s net-zero innovation portfolio. It has been identified among others as a potential solution to enable the UK to reach net zero by 2050.
But how would a solar power plant work in space? What are the advantages and disadvantages of this technology?
In space-based solar energy, solar energy is collected in space and transmitted to earth. Although the idea itself is not new, recent advances in technology have made this prospect more attainable.
The space-based solar energy system includes a solar energy satellite – a huge spacecraft equipped with solar panels. These panels generate electricity, which is then transmitted wirelessly to earth through high-frequency radio waves. A ground antenna, called a rectenna, is used to convert the radio waves into electricity, which is then fed into the power grid.
A space-based solar power plant in orbit receives the sun 24 hours a day and could therefore generate electricity continuously. This represents an advantage over terrestrial solar power systems (systems on earth), which can only produce electricity during the day and depending on the weather.
With global energy demand projected to increase by almost 50% by 2050, space-based solar power could be key to meeting the growing needs of the world’s energy sector and managing global temperature rise.
A space-based solar power plant is based on a modular design, in which a large number of solar panels are assembled by orbiting robots. Transporting all of these elements into space is difficult, costly and will have a negative impact on the environment.
The weight of solar panels was recognized early on as a challenge. However, this has been addressed by the development of ultra-lightweight solar cells (a solar panel is made up of smaller solar cells).
Space-based solar energy is considered technically feasible, largely due to advances in key technologies including lightweight solar cells, wireless power transmission and space robotics.
Importantly, the assembly of just one space-based solar power plant will require many space shuttle launches. Although space-based solar power is designed to reduce long-term carbon emissions, space launches have significant emissions and costs associated with them.
Space shuttles are not currently reusable, although companies like SpaceX are working to change that. The ability to reuse launch systems would significantly reduce the overall cost of space-based solar power.
If we can successfully build a space-based solar power plant, its operation faces some practical challenges as well. Solar panels could be damaged by space debris. Furthermore, panels in space are not shielded by the Earth’s atmosphere. When exposed to more intense sunlight, they degrade faster than those on Earth, reducing the power they can produce.
Another issue is the efficiency of wireless power transmission. Transmitting energy over long distances – in this case from a solar satellite in space to Earth – is difficult. Based on current technology, only a small fraction of the solar energy collected would reach the earth.
Pilot projects are already underway
The Space Solar Power Project in the USA is developing highly efficient solar cells and a conversion and transmission system optimized for use in space. The US Naval Research Laboratory tested a solar panel and power conversion system in space in 2020. Meanwhile, China has announced progress on its Bishan space solar power station, aiming to have a functioning system by 2035.
In the UK, a £17 billion space-based solar power development is seen as a viable concept, based on the latest Frazer-Nash Consultancy report. The project is expected to start with small trials and lead to an operational solar power plant in 2040.
The solar satellite would have a diameter of 1.7 km and weigh around 2,000 tons. The terrestrial antenna takes up a lot of space – approximately 6.7 km by 13 km. Given the use of land across the UK, it is more likely to be placed offshore.
This satellite would deliver 2GW of electricity to the UK. While this is a significant amount of electricity, it is only a small contribution to the UK’s generation capacity, which is around 76 GW.
Given the extremely high initial costs and slow return on investment, the project would require significant government resources as well as investment from private companies.
But as technology advances, the cost of launching and manufacturing will steadily decrease. And the scale of the project will allow for mass production, which should bring costs down a bit.
Whether space-based solar energy can help us reach net-zero by 2050 remains to be seen. Other technologies such as diverse and flexible energy storage, hydrogen and the growth of renewable energy systems are better understood and more easily applied.
Despite the challenges, space-based solar power is a precursor to exciting research and development opportunities. In the future, the technology is likely to play an important role in global energy supply.
This article is republished by The conversation under a Creative Commons license. read this original article.