Monday, March 31, 2014

Orbital Power Generation

Electricity is the driving force of the modern world. It powers our homes, our devices. It controls traffic and heat. For many, being without electricity would be equivalent to being without the sun each day. And this need will only continue to grow.

Electric vehicles will become more prevalent and possibly even replace gas engines. The world population is growing, with it the demand for electricity in houses and devices. Not to mention the fact that one-quarter of the world is currently without electricity and will eventually have it. Even without that growth, demand for electricity today is more than the supply. New means of power generation must be created.

As science progresses nuclear power plants may be able to move toward fusion instead of fission. This would create a great amount of power and would most likely meet the demand. But at this point that is not a viable option or even near to becoming one.

Renewables also have room for improvement but are viable. But no matter how efficient solar or wind become they will simply occupy too much space and continue to be an eyesore. While they have a small carbon footprint, their physical footprint is too large to meet future demand.

Here is the opportunity for space. There is plenty of space up in space. Anything in orbit around the Earth is invisible to the naked eye. We also have an unobstructed view giant fusion reactor at the center of our solar system, the Sun. Orbital solar power is a proven technology and is potentially a huge source of electrical power.

The reason solar power is so inefficient on earth is due to two problems. The atmosphere and engineering limitations.

The atmosphere absorbs a majority of solar energy before it ever reaches the ground on a clear day, not to mention night-time and when there is heavy cloud cover. This is not a problem in orbit because there is no atmosphere. And while there would still be day and night, they are not equal. An orbiting station can remain in sunlight for 99% of an orbit.

From the engineering standpoint, solar cells are only around 10-15 percent efficient today. However, unlike something like fusion, the performance of solar cells is increasing yearly. But there is no requirement to use solar cells either. An orbital station could just be a large mirror that focuses the sun energy onto a steam turbine in the station.

There is only one problem with a solar orbital station. How does the power get from orbit to the ground? It would have to be through wireless transmission. This could be done through microwaves or lasers. Both are proven technologies. However they require receiver stations on the ground. While these stations would have to be of a size comparable to a  standard solar station today, they would be fewer in number.

With the wireless power transmission there is a liability involved. If the transmission beam strays from the receiver station, it could potentially cause damage to nearby areas. But this is simple to control and the worst damage that has been predicted is sunburns a little more quickly.

The initial cost of the station, with current infrastructure, is too great to substantiate the construction of it. Studies performed by SERT (Space Solar Power Exploratory Research and Technology Group) found that launch costs would have to be as low as $100-$200 a pound to make the concept financially feasible. Current launch costs are at best $10,000 a pound. But with the development of reusable vehicles that price will drop to the range required.

The orbital construction costs would also be something to consider. Anyone working to create an orbital power station would want to have a very clear construction infrastructure in place. This could be robots or even a dedicated manned space construction station. Neither of these exists today. But if the power station were designed as along the lines of an inflatable that could be assembled with very few pieces the infrastructure would not be nearly as necessary.

At this moment all of the technology for an orbital solar power station exists and is proven. The trouble is that the infrastructure to build it is not in place. This is changing rapidly, but resources for such a project will not be complete enough for at least another ten years. But at that point, the demand for electricity will have risen to such a degree that orbital stations will likely be a necessity and a large business opportunity.

Below are links to the National Space Society's site concerning Orbital Solar Power Stations
NSS Space Solar Power Webpage
NSS Space Solar Power Library

1 comment:

  1. What size battery will a 100w solar panel charge?
    100 Ah 12V
    For a100w solar panel portable, a 100 Ah 12V battery would work well. Remember that your power input needs to roughly match your power output. A 100 Ah 12V battery provides around 50% usable storage.