Fossil fuels used in various aspects of life such as cooking, heating and in cars are quickly being replaced by more modern electrical alternatives. However, these advancements have no benefit to the environment since we still rely on crude oil for reliable electricity in the grid. The UK may pledge to completely abolish use of fossil fuels for energy in a few decades. However, there are still issues with forms of renewable energy that are reliable and ineffective. During peak energy consumption times, demand may be too high for renewable energy sources alone to satisfy if the wind is not blowing or the sun is not shining. Therefore, we need a more reliable source of clean energy that is powerful enough to meet the demand of consumers. In this article, I will discus the possibility of using space based solar power as a source of energy.
What is solar power?
Solar power is an advantageous and promising renewable. It has zero cost after initial installation and is widely available throughout the world. The Earth’s surface receives an estimated 120 000 terawatts of solar radiation and the Sun will shine for another 6.5 billion years according to NASA predictions; this is 10 000 times more energy hitting the earth every second than the total energy usage of the world. Thus, solar energy is a very powerful form of energy production and is sustainable in the long term.
However, it also has major drawbacks such as its unreliability due to variation in light intensity. Due to the absence of sunlight, solar power cannot be generated at night, and less is available during the winter, although this is when energy consumption is higher. Solar power is also fairly ineffective in places that are often cloudy, such as the UK. If we are to move forward as a society with purely clean forms of energy we must solve these problems.
One way to achieve reliable solar energy production is to remove these problems physically; in other words, remove the atmosphere. To do this, we can send solar panels into space. This removes the problems posed by clouds, atmospheric scattering of the light and night-time. This means that Space Based Solar Panels can collect eight times more energy per second. They can also function continuously as they can be made to face the sun for the entire 24 hour day.
The reason that this concept may sound like a far-fetched science-fiction idea. This is because it was actually first conceived by science fiction writer Isaac Asimov in his story ‘Reason’. At first it seems questionable; this is because although the idea solves existing issues with conventional solar energy, other problems arise such as how the energy that is collected would be transported back to earth. A 36 000 km long wire to space seems impractical. So, in order to overcome this, the energy that is converted from light photons into electrical energy by the solar panel can then be transformed into some kind of electromagnetic wave which is beamed back to earth. These waves are received and transformed back into electricity which can be put into the grid as consumable energy.
However, electromagnetic waves can vary vastly in properties. From highly dangerous gamma radiation to much lower energy radio waves which can safely pass through humans. The current most popular contenders for transmission waves are laser beams (in the visible or infrared light spectrum) or microwaves. Both of these are safe when interacting with humans, birds and planes. Lasers are easily scattered by the atmosphere. They are therefore very inefficient compared to microwave transmission, which is about 80% efficient.
The drawbacks of space based solar power
Unfortunately, the large, heavy equipment required to transfer electricity into microwaves for microwave transmission would increase the amount of money and fuel required to get the solar panels into space. Therefore, to incorporate the best of both transmission types, it has been proposed that lasers can be used in space.This is where they are still highly efficient. They will then be captured by a secondary satellite in lower orbit. The laser beams would be transferred here into microwaves where they are more efficient through the atmosphere. This means that bulky equipment is not needed on the solar panels themselves, reducing launching costs but also using the most efficient means of transmission. Several panels can transmit laser light to one microwave transmission satellite to reduce the amount of bulky and expensive equipment needed.
How realistic is this?
How far away is this technology? Although there were some hurdles to overcome, the basic technology has been around for a very long time. The only significant barrier to implementation was the cost of launch. The idea was considered by NASA in the ‘70s, but the solar panels were too heavy to launch into space. As technology has improved, streamlining our design and lowering costs of satellite launch, the idea has become more and more feasible. In fact, the California Institute of Technology currently has a working prototype of solar panels intended for space. This demonstrates the lightest wirelessly transmitting solar panel by an entire order of magnitude. With institutes in China, India, Europe and America all currently working towards this technology, it is reasonable to think that we may be relying on solar power from space sooner than most people would expect.
Article by – Leah de Wet