expaand

Oil as an energy source has many problems. It is harder to come by these days (even though it is very possible oil is continually seeping up deep from within the earth). A lot of the oil exists in politically unstable areas. So oil is responsible for much war and economic dislocation.

Coal, while plentiful, is filthy - at every level, there is an extreme negative environmental impact from its processing. And its combustion.

And the burning of oil and coal, along with natural gas, in addition to any other pollution, produces tremendous amounts of CO2. Whether you believe that this is definitely harmful or not (while the evidence suggests that it might very well be), it certainly makes sense to be prudent with something so potentially devastating.

So in the long run, the use of so-called fossil fuels for energy, which have powered our society for over 100 years is doomed.

Nuclear energy has its own set of problems. One critical issue is what to do with long-lived nuclear waste, and that has never been solved, and might never be. This could be nuclear energy’s death knell.

Wind, tides, geothermal - they are all nice, but hardly provide enough juice to power our world.

So that leaves solar. Which might be the only sure fire way to propel us to the next generation. It has been said that more solar energy hits the earth in an hour then is used by the worlds’ societies all year. Of course, collecting that energy is the challenge, since the density of solar energy hitting the earth in any given area is rather low. But the density is high enough, given efficient collection devices. Solar cells really could be everywhere - on every surface exposed to the sun, such as roofs, car-tops, vacant lots. But solar is intermittent. No matter what is done at the collection front, without an efficient storage system, energy from the sun is not practical.

The way to store solar energy is in the form of hydrogen. Use energy from the sun to split water into its constituent atoms (electrolysis), and store the hydrogen in some convenient form. How, then, do you use the hydrogen? Well, other then directly burning it (which could be done, say, in a special engine), the best way is the fuel cell. The fuel cell is just the reverse of the electrolysis which produced the hydrogen in the first place - combine the hydrogen with oxygen in a controlled manner, say via a special membrane, to produce electric power on demand. And a sole byproduct: water.

So for us to survive, our future has the following:

1. efficient solar cells everywhere, producing electric power directly, as well as hydrogen which is stored and collected;
2. fuel cells everywhere (as well as in central power stations), making use of this hydrogen to generate electricity when and where it is needed.

A solar-hydrogen economy.

This is currently our greatest challenge - to develop the technologies, infrastructure, industries and political will for this to all be possible. With a potential huge windfall - our survival!