Solar power stations in space?

Energy Nov. 20, 2020

A blog written by Omar Faid.

The idea of huge solar farms in space sounds ridiculous, like something out of a sci-fi movie. We already have enormous solar farms on earth like the Tengger Desert Solar Park in China that produces up to 1,547MW of power. Now, you are probably thinking that that is a lot of power and it is. In fact, that’s enough energy to power a whole city which is insane.

The problem is that this is only 40% of the power that the farm actually produces. Up to 60% of the energy is regularly lost mainly due to the atmosphere and its elements. Numerous physicists and engineers have repeatedly theorized about the feasibility of space-based solar energy. The proposals are numerous and varied - from thermal power plants on the moon to swarms of solar panels that orbit the sun directly and yet it always seemed like a futuristic dream.

Construction, engineering, and financial hurdles:

Why hasn’t it been constructed yet?

Technical challenges such as huge temperature differences of several hundred degrees within a few millimeters between the front and back of the panels are hard to overcome with our current technology. One other key aspect is the fact that we are going to have to launch such a huge structure into space which is currently, basically impossible. A single solar power station may have to be as much as 10 kilometers squared in area which is the equivalent of more than 1000 soccer stadiums.

In an ideal world, a best-case-scenario if you will, a very light version of a solar power plant could be assembled in space. The materials required for this would weigh around 4000 tons and could be launched into low orbit with around 50 rocket launches. This whole process would cost about 11 billion dollars.

Energy transfer:

The question of how the recovered energy is supposed to reach earth again remains a mystery. In fact, fixed cables were also considered but with the current materials, however, this path seems impossible. That is why the idea of wireless transmission is growing into a more considerable option.

The solar energy absorbed by the collectors is converted into electrical energy with the help of photovoltaic systems. It is then sent to the earth by microwave rays, where it is captured by a field of collectors that are several square kilometers wide and converted back into electrical energy. Other approaches target lasers, which would scatter far less, but are theoretically more dangerous than radio waves.

Wireless energy transfer based on ideas from Nikola Tesla are very promising. It has already been successfully tested. In 2008, US scientists "sent" 20 watts of solar power via microwaves over 148 kilometers from Maui to Hawaii. In 2015, Japanese scientists transmitted ten kilowatts over 500 meters. In the case of transmission from space, the dimensions would be much larger, but it is technically possible and at the same time harmless to humans.

The future:

Imagine a world that is only powered by clean renewable energy. Solar farms in space could prove to be a viable option in the future. This technology has the huge potential to save our planet from the pollution we create on earth.