Sustainability, now there is a good word.  It follows on easily from optimisation and is just as complex an issue.

The easiest way to look at sustainability is to think of the world and what it might be like in a few hundred years’ time.  I know; that is pretty much an impossibility.  But we can think about what issues there might be.  Resources are going to be a big one, whatever our new and exciting technological discoveries produce during that time period.

If we keep going at our current rate of throw-away use, that future world will have some very serious issues to sort out.  One side of that dilemma is to find new resources, either deeper than previously discovered or perhaps under the oceans, or even by mining asteroids or the moon. The best chance of utilizing these new resources is to give ourselves plenty of time to be able to access them cleanly and effectively.

That sort of thinking soon gets you to think about not wasting current resources, or recycling them so that more of those materials are still available to future generations.  It would be a great thing if we can still be making long surviving plastics from hydrocarbons in, say five hundred years’ time. Not so for throwaway straws.

So, do we waste buried hydrocarbons by burning them for fuel when there are plenty of alternatives that are more sustainable?  If electricity is cheaper and more sustainable from a direct solar source, shouldn’t we embrace it whole heartedly?  That way hydrocarbons will be available to humanity for a much longer time period.

On the other hand, batteries with the current technology are not a very sustainable resource.  It would be a better option if we used them more appropriately.  Lithium-ion batteries are a great modern invention, thanks to John Goodenough and with any luck he has some more good battery ideas up his sleeve.  They are great for small, wearable items like phones and watches as they offer a great energy supply with little weight.  That means they are also great for transport and they really do reduce pollution levels within cities.

With a billion Internal Combustion Engine vehicles currently on our roads, we have a major optimisation problem in front of us.  Do we banish them all and build a billion new EVs?  I calculated once that we would need to double our aluminium output and use all the world’s known lithium and cobalt resources to do that and in twenty years’ time do the same again.

To get to something vaguely sustainable we need to use some pretty clever optimisation techniques and try to use the best option for each of our requirements. A harvester on a farm is probably not the best use for a lithium battery as it will only ever be used for a few months a year.  A liquid (or gaseous) fuel would be a better bet, perhaps hydrogen or better still, ammonia. 

Grid backup for solar electricity generation is also not a great use for lithium batteries.  Weight is not important, so let’s use some other storage, be it battery (vanadium flow) or something else (a flywheel for example).  Similarly with home power tools, lawn mowers etc. They don’t need to be battery operated.  Fair enough if you are a tradie using tools every day, but not for the rest of us.  Even tradies might find some of their tools are better being plugged in so as not to run out of battery at an inopportune time.

Yes, new technology will help out along the way in largely unknown ways.  But to help that technology along, we need to be in the game in the first place.  We need multiple battery types that are fit for purpose together with liquid energy storage and we need to be developing the technology in many different areas all at the same time.  If we go full lithium battery, then we urgently need a recycling system that does not use an inordinate amount of energy or new materials.

Are we better off keeping current vehicles on the road as long as we can, rather than replacing them all instantly?  We would need to clean up those ICE vehicles remaining, again perhaps running on a gas mix including hydrogen.

Technology that converts methane (CH4) directly into solid carbon powder and hydrogen is brilliant, but currently expensive.  Imagine if we could convert gas hydrates into usable fuel, instead of just allowing their eventual escape, creating a major global disaster.