Reimagining Space: An Introduction to Space Based Solar Power

In this article for our Reimagining Space series, we’re exploring the concept of space based solar power, and the role this new technology could play in our journey to net zero.

Since the dawn of the space age, we have been transfixed with not only the spectacle of space exploration, but also the opportunities that this new vantage point provides for technological advancement. Today by combining the advances in launch capabilities and innovative manufacturing, we are now in a position to develop the infrastructure for a space based solar power system capable of providing clean energy for planet Earth. This idea is an old one, but it’s the recent advances in our capabilities that are helping to make this possible for our future.

With the UK committed to fully decarbonized by the year 2050. A major consideration is the delivery of energy through clean generation from renewable sources, and that the energy we generate must remain affordable, reliable and secure for our economy continue to prosper. This is where space based solar power stands out from the alternatives.

THE CHALLENGE

In 2050, we’re going to need to generate about 50 billion megawatt hours of electricity to power the world. Currently, we’re only producing around 20 billion megawatt hours and we have a population of around 7 billion.

2 billion of that 7 billion people currently have no access to primary electricity, they’re using primary biomass as fuel. So there’s a huge shortfall of around 40 billion megawatt hours, and that means we need to generate an additional 4 million megawatt hours per day for 10,000 days to hit the predicted demand in 2050.

To put that in context, that’s the need to add 100 square kilometers of solar panels every day for 10,000 days, or around 650 wind turbines per day, or Hinkley Point C, one of the big fission reactors every week for 10,000 days. That’s the size of the challenge ahead of us, and there really is no silver bullet. We’ll need to incentivize energy efficiency, we are going to have to rapidly accelerate renewables. But even with those actions, there is a huge gap for new baseload technologies.

HOW IT WORKS

There are a number of studies which take the science fiction away from Space-Based Solar Power.

The basis of the technology is a large spacecraft with photovoltaic cells, very much like the solar cells on Earth, but at a higher concentration. By reflecting the sun onto those PV cells, and then transforming that energy we can create a microwave energy beam, and transmit that microwave beam onto the earth and collect it using a receiver.

It sounds a little bit more simple than it is, of course. The spacecraft is extremely large, and it will require many launches in order to put it together into space. But one of the beautiful things about this new baseload technology is we understand the physics of all of it, it’s a mass production challenge and it’s a logistical challenge, rather than trying to figure out the physics.

But in the end, we will have a single spacecraft providing two gigawatts of power in a geostationary orbit of Earth. The idea is then to launch many more of these satellites, and provide a sustainable, clean energy source available at any time of day or night and in all weathers.

Over the last 10 years, four or five things have happened to make this technology more feasible. It has always been considered technically viable, but economic unaffordable. With the advent of reusable rockets, the price of launch to low Earth orbit has come down by 90%. And the cost of space hardware has come down by 99%. It’s only 1% of what it used to be, as evidenced by things like the OneWeb and the Starlink satellite constellations. Then, all of the underpinning technology, like in-space robotics, is maturing as well. Finally, high concentration, high efficiency photovoltaics have become much more capable and affordable. If you overlay these advances with the real urgency to decarbonize our economies, and develop these new forms of baseload power, it really means that it’s now not only technically viable but economically affordable.

THE BENEFITS

There’s some really exciting and quite unique features and characteristics about space based solar power. As a nation, it allows us to have sovereign secure energy. But it also allows us to collaborate with our natural partners in a way that you just can’t do with any other power source, because you can beam it to other places.

Anybody with a compatible rectenna can receive power. That opens up the opportunity to work with developing nations who are really going to struggle to decarbonize without making difficult decisions, if they can’t just move off fossil fuels, until they’ve got a viable and affordable alternative source of energy. If they can receive energy through space based solar power without having to build the complicated infrastructure of energy generation, just by having the receiving antennas, that could be game changing.

This article is a summary of discussions made during the recording of our In-Orbit Podcast Series.