Humanity's demand for energy is growing at an astonishing rate. Combine this with an ever-dwindling supply of fossil fuels, and it becomes painfully clear that something innovative and powerful is required. There's one high-tech proposal that holds tremendous promise — an idea that has been around since the late 1960s. Here's how space-based solar power will eventually solve all our energy needs.
Humans needs more power
Assuming that economic progress and globalization continues at its current pace, we'll need to produce twice the amount of energy that's consumed today by the 2030s — what will reach a monumental 220 trillion kiloWatt hours per year. And by the end of the century, we'll need four times the current rate of consumption.
Just as importantly, we're also going to have to kick the fossil fuel habit — and not only because it'll eventually run out. Rising CO2 emissions are wreaking havoc on the Earth's atmosphere, what's creating environmentally deleterious side-effects at a rate faster than expected.
Moreover, if greenhouse gases are to be brought under control over the course of the next several decades, we'll need to get upwards of 90% of all our energy from either renewable or nuclear sources.
While there are a number of proposals on the table for how we might be able to meet these challenges, none really appear to be truly viable.
Except for solar powered satellites.
Obvious benefits
A closer look at a space-based solution yields a lengthy list of advantages.
Solar powered satellites don't produce any greenhouse gases, nor do they take up valuable real estate on Earth. Once the initial costs are met, they would be relatively cheap to maintain; the solar modules used for generating solar energy have a long service life, not to mention the astounding ROI that would come from a virtually unlimited energy source.
Additionally, they're not constrained by night/day cycles, the weather, or the changing seasons. And indeed, they would be much more efficient than any kind of ground-based station. The collection of solar energy in space is seven times greater per unit area than on the surface of the planet. Moreover, the amount of solar energy available up there is staggering — on the order of billions of times greater than what we draw today; the Earth receives only one part in 2.3 billion of the Sun's output. The potential for scalability is enormous, to say the least.
Solar powered satellites won't be prone to terrorist attacks and they'll reduce geopolitical pressure for oil. According to futurist Keith Henson, space-based solar could be used to power vehicles, like electric cars, or by enabling the production of synthetic fuels — which at a penny per kiloWatt hour would result in gasoline that costs one dollar a gallon.
At the same time, space-based solar would provide true energy independence for those nations who choose to implement it. And on top of that, the energy could be exported to virtually anywhere in the world; it would be especially valuable for isolated areas of the globe, including Africa and India.
Lastly, space-based solar power would also yield tremendous benefits to human and robotic space exploration, including the powering of off-planet colonies on the Moon, Mars, and space stations. It could also serve as the first seed in the development of a Dyson Sphere — a massive array of solar collectors that would completely envelope the sun at a distance of about 1 AU.
How it's going to work
Back in the late 1960s, Peter Glaser proposed the idea of solar powered satellites (SPS), what he envisioned as space-based photovoltaics that could transfer energy wirelessly back down to Earth. His design called for a large platform positioned in space in a high Earth orbit that would continuously collect and convert solar energy into electricity. In turn, that power would be used to drive a wireless power transmission (WPT) that beams the solar energy to receiving stations on Earth — what would be comprised of massive receiving dishes.
A number of visionaries have updated Glaser's vision to include the use of a microwave wireless power transmitter. This would involve large discrete structures (like a solar array and transmitter) that would have to be assembled in space. SPS systems could also include a modular electric/diode array laser WPT concept, involving self-assembling solar power-laser-thermal modules. Other designs call for an extremely modular microwave WPT SPS "sandwich structure" concept, requiring a significant number of small solar power-microwave-thermal modules that would be robotically assembled on orbit.
But to make it happen, we'll need to develop low-cost, environmentally-friendly launch vehicles. Eventually we'll send the materials up in a space elevator, but until then we'll have to come up with something more efficient. Thankfully, SpaceX and other private firms are already working on more efficient launch solutions.
Additionally, we'll require large scale construction and operations stations in orbit — space-based workplaces that would be more complex, larger, and more energy-demanding than the ISS. They would allow for the production of large, simple panels, that are easy to assemble and consist of many identical parts. Eventually, it may be possible to construct an entire flotilla of these solar collectors using materials extracted from asteroids.
Design proposals
As word gets out about the potential for SPS, and as the technology catches up to the idea, a number of design proposals have been put forth; this isn't just idle speculation anymore — it's something that's just about ready for prime-time.
For example, there's SPS-ALPHA (Solar Power Satellite via Arbitrarily Large PHased Array) which is being developed by NASA's John Mankins. Using a "biomimetic" approach, the project calls for huge platforms constructed from tens of thousands of small elements that could deliver tens to thousands of megawatts via wireless power transmission.
It would do this by using a large array of individually controlled thin-film mirrors outfitted on the curved surface of a satellite. These adjustable mirrors would intercept and redirect incoming sunlight toward photovoltaic cells affixed to the backside of the solar power satellite's large array. The Earth-pointing side of the array would be tiled with a collection of microwave-power transmission panels that generate the coherent, low-intensity beam of radio frequency energy and transmits that energy to Earth.
And what's particularly cool about this concept is that it would enable the construction of a solar-power satellite that can be assembled entirely from individual system elements that weigh no more than 110 to 440 pounds (50 to 200 kilograms), allowing all pieces to be mass produced at low cost.
There's also Japan's JAXA's SBSP System. The Japanese space agency want to get a prototype up and running by 2020, and a fully operational system by 2030. Their system is designed to run in a stationary orbit about 22,400 miles above the equator where it will absorb the sunlight with chromium-enhanced solar cells. The SBSP System will transmit energy to Earth using laser beams at about 42% solar-to-laser energy efficiency. Each satellite will beam the energy to a 1.8-mile wide receiving station that'll produce one gigawatt of electricity — what's enough to power 500,000 homes.
Other examples include the Sun Tower, the Dyson-Harrop Satellite (which would harness solar wind power), Solar Disc, and the European Sail Tower SPS.
Timelines
SPS systems have been discussed since the 1970s and have been reviewed periodically by various stakeholders in United States and elsewhere — but the idea has never been seen as something that's cost effective or technologically feasible. These sentiments are changing, however.
Last year, the International Academy of Astronautics published an exhaustive report lauding the benefits of space-based solar power, urging the international community to take the prospect seriously. The report contained over a dozen recommendations on how to get started, while predicting that space solar power will be technically feasible within 10 to 20 years using technologies that already exist.
The authors also noted that the project would be economically viable in the next several decades, but under specific conditions having to do with future energy markets and the willingness of governments to get started (what could be motivated by environmental concerns).
Additionally, flight experiments will be required, as will be the ironing-out of any policy or regulatory issues — what could definitely take some time. Needless to say, some groups and individuals may take great exception to the idea of having microwaves and laser beams shooting down onto the Earth's surface — not to mention the nightmarish potential for the weaponization of this technology.
And in terms of expense, the IAA proposed a cost-sharing scheme in which nations would work together to bring the price down — what could cost as much as a trillion dollars.
But given the incredible benefits — not to mention the tremendous need — it's a no-brainer that this needs to happen.
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