The Power Problem for Gaia

This topic may sound a bit dry to some readers, but I have to admit that I find the history of technology as fascinating as that of military history – which is why I have aspects of both in my writing. So, continuing the discussion of retrofuturism in the Iskander series stories…

The Iskanders begin the prime mover development cycle the way we did on Earth because steam plants can be easy to teach operators and mechanics to ‘drive’ and because they can be built with less sophisticated production facilities and materials. The simple one stage single or double-acting reciprocating machine is neither powerful nor efficient, but is a cheap solution that works. Simple fire tube locomotive type boilers fueled by coal or wood are also easy to train personnel to run.

The developments to triple expansion, to economizers, and to superheated steam generated in water tube boilers of higher pressures are all linear and logical improvements. The production machinery and materials to make them can also be progressively introduced into the production lines. The steam turbine is a quantum jump, but would present no more technical difficulties to make than it did our forefathers in the early 20th century. Perhaps I’m being very timid in suggesting such a development route, but I think it would be easier to educate a previously uneducated workforce via this progression than by going straight to fuel cells, or gas turbine electric systems – for example.

The fuels require consideration. My own feeling is that burning crude oil and natural gas as prime mover fuel is a criminal waste of valuable resources. Oil should only be used for lubricants, and natural gas for plastics. However, their obvious advantages over coal (ease of handling and low ash) would inevitably make it supremely difficult to keep them out of furnaces and internal combustion engines. The answer is, of course, to limit the use of steam and internal combustion engines to the fewest number of years that one can by superseding them with something better. Electrification must be started as early as possible.

It is axiomatic that a star traveling society has mastered the production of cheap electricity from efficient fusion power. No star travel would be possible without the amounts of energy developed from the fusion reaction. My conception would be that the Iskanders would begin building fusion powerplants as soon as they had the highly skilled workforce and precision machine tools available. It could take fifty years, to my mind. Enough for the first retrained blacksmiths to father a generation of mechanics, and for them to father a young generation of technologists. (Many writers have pointed out that it takes a mechanically minded generation to educate and train offspring that can learn enough to make the next step.)

The need for fusion fuel is why the Iskanders have the priority mission assigned to the Oceanographers – “Find a suitable location for our heavy water separator and the tritium plant”. A fusion reactor converts heavy hydrogen, the H2 deuterium and H3 tritium, into helium – while releasing a great deal of energy, as in a hydrogen bomb. The oceans, lakes, and rivers (as well as the gas giant planets and their satellites) offer an abundant and virtually unending supply of the hydrogen needed. Deuterium is present in water at a ratio of 1 D2 atom to every 6500 atoms of H1. Heavy water, where the lighter H atoms are replaced by D atoms is 10.6% denser than ordinary water – deuterium ice sinks in normal water. To convert the D2 atoms to T3 atoms for the fusion reactor requires them to be bombarded by high energy particles – most simply in a nuclear fission reactor, like that at Chalk River in Canada which produces more than 50% of the world supply of medical isotopes.

We owe our existence and the whole biosphere of the Earth to the energy released by the fusion reaction – the sun runs on this cycle. The reaction on the sun uses ordinary hydrogen and takes place at a temperature of several million degrees Celsius. The trick in producing a powerplant on Earth that works on hydrogen has been to use H2, H3 and Lithium to persuade the fusion to take place controllably at lower temperatures. No one has succeeded in developing a workable, power generating fusion plant yet – all the test designs have needed more power in, to promote the reaction, than the reaction has produced. However, hopes are high for eventual success with either the Tokamak model – a veritable monster machine like a fission reactor within huge containment magnets – or perhaps the Stellarator. I suggest this design for the Iskanders, whose need is for a reactor small enough to tuck into a starship or a space plane. I suspect such a machine requires the same super-precision in its construction as does the latest European stellarator design. Hence the need for a highly skilled workforce.

So, next week I will continue the topic of power and fuels, and suggest how that bane of human society – the automobile – can be avoided on Gaia.


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