Solar power plants in space could be the answer to our energy needs

It sounds like science fiction: gigantic solar power plants floating in space that radiate enormous amounts of energy to Earth. And for a long time, the concept – first developed by Russian scientist Konstantin Tsiolkovsky in the 1920s – was primarily an inspiration for writers.

A century later, however, scientists are making huge strides in making the concept a reality. The European Space Agency has realized the potential of these efforts and is now seeking to fund such projects, predicting that the first industrial resource we will get from space will be “radiated power”.

Climate change is the biggest challenge of our time, so the stakes are very high. From rising global temperatures to changing weather patterns, the impacts of climate change are already being felt around the world. Overcoming this challenge will require radical changes in the way we generate and consume energy.

Renewable energy technologies have developed dramatically in recent years, with greater efficiency and lower costs. But one of the main obstacles to their absorption is the fact that they do not provide a constant supply of energy. Wind and solar farms only produce energy when the wind blows or the sun shines, but we need electricity 24 hours a day, every day. Ultimately, we need a way to store energy on a large scale before we can move to renewables.

Benefits of space

One possible way around this would be to generate solar energy in space. There are many benefits to this. A space solar power plant could orbit to face the sun 24 hours a day. The Earth’s atmosphere also absorbs and reflects some of the sunlight, so solar cells above the atmosphere will receive more sunlight and produce more energy.

But one of the key challenges to overcome is how to assemble, launch and deploy such large structures. A single solar power plant can have an area of ​​10 square kilometers, equivalent to 1,400 football fields. The use of lightweight materials will also be key, as the biggest expense will be the cost of launching the station into space on a rocket.

One proposed solution is to develop a swarm of thousands of smaller satellites that will join and configure to form a single large solar generator. In 2017, researchers from the California Institute of Technology outlined plans for a modular power plant, made up of thousands of ultra-light solar cells. They also demonstrated a prototype tile that weighs just 280 grams per square meter, similar to the weight of paper.

Recently, developments in manufacturing, such as 3D printing, are also being examined for this application. At the University of Liverpool, we are exploring new manufacturing techniques for printing ultralight solar cells on solar sails. A solar sail is a foldable, lightweight and highly reflective membrane that can harness the pressure effect of solar radiation to propel a spacecraft forward without fuel. We are exploring how to embed solar cells on solar sail structures to create large fuel-free solar power plants.

These methods would allow us to build power plants in space. Indeed, it may someday be possible to fabricate and deploy units into space from the International Space Station or the future lunar access station that will orbit the moon. Such devices could indeed help deliver energy to the moon.

The possibilities don’t end there. While we currently depend on Earth’s materials to build power plants, scientists are also evaluating the use of resources from space for production, such as materials found on the moon.

Another great challenge will be returning power to the Earth. The plan is to convert electricity from solar cells into energy waves and use electromagnetic fields to transfer them to an antenna on the earth’s surface. The antenna will then convert the waves back into electricity. Researchers led by the Japan Aerospace Exploration Agency have already developed designs and demonstrated an orbiter system that should be able to do this.

There is still a lot of work to be done in this area, but the goal is that solar power plants in space will become a reality in the coming decades. Researchers in China have designed a system called Omega, which they aim to make operational by 2050. This system is expected to be able to deliver two gigawatts of power to the terrestrial grid at peak performance – a huge amount. To produce that much energy with solar panels on Earth, you would need more than six million of them.

Smaller solar-powered satellites, such as those designed to power lunar rovers, may be operational even earlier.

Around the world, the scientific community is devoting time and effort to developing solar power plants in space. Our hope is that one day they can be a vital tool in our fight against climate change.

This article was republished by The conversation under a Creative Commons license. Read the original article.

Image credit: NASA