The UK government is reportedly considering a £16 billion proposal to build
a solar power station in space.
Yes, you read that right. Space-based solar power is one of the technologies
to feature in the government's Net Zero Innovation Portfolio. It has been
identified as a potential solution, alongside others, to enable the UK to
achieve net zero by 2050.
But how would a solar power station in space work? What are the advantages
and drawbacks to this technology?
Space-based solar power involves collecting solar energy in space and
transferring it to Earth. While the idea itself is not new, recent
technological advances have made this prospect more achievable.
The space-based solar power system involves a solar power satellite—an
enormous spacecraft equipped with solar panels. These panels generate
electricity, which is then wirelessly transmitted 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 delivered to the
power grid.
A space-based solar power station in orbit is illuminated by 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 produce electricity only during the day and depend on the
weather.
With global energy demand projected to increase by nearly 50% by 2050,
space-based solar power could be key to helping meet the growing demand on
the world's energy sector and tackling global temperature rise.
Some challenges
A space-based solar power station is based on a modular design, where a
large number of solar modules are assembled by robots in orbit. Transporting
all these elements into space is difficult, costly, and will take a toll on
the environment.
The weight of solar panels was identified as an early challenge. But this
has been addressed through the development of ultra-light solar cells (a
solar panel comprises smaller solar cells).
Space-based solar power is deemed to be technically feasible primarily
because of advances in key technologies, including lightweight solar cells,
wireless power transmission and space robotics.
Importantly, assembling even just one space-based solar power station will
require many space shuttle launches. Although space-based solar power is
designed to reduce carbon emissions in the long run, there are significant
emissions associated with space launches, as well as costs.
Space shuttles are not currently reusable, though companies like Space X are
working on changing this. Being able to reuse launch systems would
significantly reduce the overall cost of space-based solar power.
If we manage to successfully build a space-based solar power station, its
operation faces several practical challenges, too. Solar panels could be
damaged by space debris. Further, panels in space are not shielded by
Earth's atmosphere. Being exposed to more intense solar radiation means they
will degrade faster than those on Earth, which will reduce the power they
are able to generate.
The efficiency of wireless power transmission is another issue. Transmitting
energy across large distances—in this case from a solar satellite in space
to the ground—is difficult. Based on the current technology, only a small
fraction of collected solar energy would reach the Earth.
Pilot projects are already underway
The Space Solar Power Project in the US is developing high-efficiency solar
cells as well as a conversion and transmission system optimized for use in
space. The US Naval Research Laboratory tested a solar module and power
conversion system in space in 2020. Meanwhile, China has announced progress
on their Bishan space solar energy station, with the aim to have a
functioning system by 2035.
In the UK, a £17 billion space-based solar power development is deemed to be
a viable concept based on the recent Frazer-Nash Consultancy report. The
project is expected to start with small trials, leading to an operational
solar power station in 2040.
The solar power satellite would be 1.7km in diameter, weighing around 2,000
tons. The terrestrial antenna takes up a lot of space—roughly 6.7km by 13km.
Given the use of land across the UK, it's more likely to be placed offshore.
This satellite would deliver 2GW of power to the UK. While this is a
substantial amount of power, it is a small contribution to the UK's
generation capacity, which is around 76GW.
With extremely high initial costs and slow return on investment, the project
would need substantial governmental resources as well as investments from
private companies.
But as technology advances, the cost of space launch and manufacturing will
steadily decrease. And the scale of the project will allow for mass
manufacturing, which should drive the cost down somewhat.
Whether space-based solar power can help us meet net zero by 2050 remains to
be seen. Other technologies, like diverse and flexible energy storage,
hydrogen and growth in renewable energy systems are better understood and
can be more readily applied.
Despite the challenges, space-based solar power is a precursor for exciting
research and development opportunities. In the future, the technology is
likely to play an important role in the global energy supply.
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Tags:
Space & Astrophysics