Apr 302013

Alternative energy; but just how much fossil carbon is there?

‘…and what will men burn when there is no coal? Water. Yes, my friends, I believe that one day water will be employed as a fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light.’

So wrote Jules Verne, the father of science fiction, in his 1875 novel Mysterious Island. And sometime this century his prediction might well come true. Of course we won’t be using water as such, but if we really can harness science and technology to solve the world’s energy needs, then we might well be using the hydrogen it contains. Some catalysts are already known which can convert water to hydrogen by the action of sunlight, although their efficiency is still only around 5%.

Can we really transform the world into one that no longer needs fossil fuels? What can replace the energy that they provide and which now meets most of our needs? Some countries are well on their way to achieving sustainable energy, while others are finding it less easy to move in that direction. If we could gather and use a mere 1% of the energy that the Earth receives from the Sun then our problems are solved. It’s a simple as that – and it’s as difficult as that. Moreover we have a large moon which moves our huge oceans endless to-and-fro and that energy might be used, and we are sitting on the thin crust of a sphere of molten magma whose vast energy store we might also tap into.

Of course we could still rely on fossil energy and there is indeed an awful lot of this as you can calculate using a simple bit of chemistry. The oxygen of the atmosphere has all come from carbon dioxide (CO2) and for every O2 that is released then there must be a C somewhere on Earth.  The amount of that carbon can be calculated from the amount of O2 in the Earth’s atmosphere which amounts to 1015 tonnes, which is a 1,000,000 billion tonnes. That being so then there must be 350,000 billion tonnes of carbon in the Earth’s crust. Of this we extract 10 billion tonnes a year, which is only 0.003%. In a hundred years at the present rate of extraction we will use only 0.3% of what is there.

Of course if we do this then we might well have an impact on the environment that will affect us all. And there may be unexpected consequences as well. No, the answer is to use science, and especially chemistry, to generate renewable energy and ensure that what we do produce is not wasted on inefficient heating and inefficient transport.