|Now I discuss - at least I guess so - all major important aspects of
energy production, consumption and reduction of the last and draw my conclusions,
which in my view can be hardly denied by any realistic and not preoccupied
approach. I assure you, most of you will not like my conclusions. But we
got a simple duty in our situation, while the new millenium is pending:
survival by avoiding all devastating behaviour on a global scale. And you
will see, in reality our options to choose are very rare, if there are
alternatives at all. For example, the todays massive use of cars with combustion
engines have to cease and must be replaced either by an enormous reduced
one with lower emissions or changed to a non-emission system without combustion
products. Both variants together seem to be the optimum...
The discussion begins...
The first aspect to consider is: which ways of energy production are at all capable of contributing large parts of the global needed power? Connected with this is the question, if the source is available for a short, medium or rather long time. Finally of course the consequences for our biosphere and therefore also ourselves must be taken into account.
For the first reason I disregard sources as wind, tide, geothermal or water: the potential amounts of these are far to low. Besides, at least the usage of dams and associated power stations is a threat for the local environment, as it can be seen in all parts of the world. The other sources are simply overestimated in their potential. You can figure this out by making barely realistic assumptions about large usage of them and you will only discern, that even than they deliver not enough power to be relevant at all.
With organic resources there is often heard, that usage of special dedicated fields of plants should deliver a carbon dioxide neutral energy by burning. In principal true, this way we can't choose for a total different reason: the ever growing population of humans on the Earth requires desperately, that all possibilities of food production are used to their fullest extent. We have simply no ground left for the mentioned usage as energy delivering acres. It's a good example for a too narrow view of real potentials and consequences...
The other organic resources have all in common, that their use threatens the entire biosphere by emission primarily of carbon dioxide alongside with hydrocarbons (especially Methane). In the cases of earth gas and oil the additional problem is, that they have very limited amounts which can be used. A simple and regretfully realistic estimation of constant or further growing use of them leads simply into depletion innerhalf a few decades: many of us (not the current reigning politicians of course!), especially the younger people, will witness the exhaustion of these resources.
The coal on the other side has at least a ten, eventually hundred times greater potential to deliver enough energy, but only at the inpayable prize of heating our atmosphere to no end. I have to remark, that statements, that the human caused additional greenhouse effect doesn't exist or is neglectable, are simple lies without any responsible posture, mostly driven by interest groups, which fear about their earnings... This threat is absolutely real - despite it's not possible, to determine it now with a 10% accuracy.
Nuclear fission is a resource, which doesn't heat explicitly our planets atmosphere (that means no more than other, non-burning activities) and even without Plutonium usage and fuel renewal it can work for a long time, at least a hundredfold more than coal. In carefully chosen underground sites it has to be and in my opinion indeed can be stored for a long time, and usage of modern reactors with an high level of safety can reduce the potential risk to an absolutely acceptable level, especially if old reactors are taken offline after an adequate time and new ones are build according the state of the art technology. By using these advances and/or usage of systems with inherent safety, this would work for a long time without any real threat to us. For example the millions of human made chemicals, which are poured without real control or knowledge into our biosphere, are a much greater threat to our lifes than most people recognize, than carefully stored radioactive wastes.
Solar energy has a virtually unlimited usage time - at least only limited by our suns lifetime, which clearly doesn't matter. But it has nowadays two drawbacks: the principal, natural caused one is the lack of continuity of it by the varying insolation throughout location on Earth, time of day and year and changes in cloud cover. This fact requires storage of energy especially at winter times in non-equatorial latitudes and for the reason, that most high energy consuming areas not conincide with the zones of high average insolation, also transport of energy over great distances is also a must - connected with losses at this transfer. A not so principal, but todays limitation of a very severe type is the very low efficiency of solar cells. This induces the following consequences: the consumption of areas is very high and connected with a big, energy consuming need of carrying structures and cells itself. The ultimate problem is now, that by limited lifetime of these cells with efficiencies below 20% (realistic today around 15 % at most) the time, which is required, to substitute the energy gained by insolation is comparable with this lifetime. If you don't comprehend immediately, what this means, here is it: the net energy gain is around zero... But this obstacle should be overcome by an increase in efficiency to 50% or more; the CCD chips have demonstrated, that so-called quantum efficiencies of 70% and more are possible. This gives a hint, that also the energy efficiency of solar cells should be raisable to the needed values.
Nuclear fusion is an even greater challenge. It's usage time exceeds by far even that of nuclear fission, and despite falling short compared with solar energy, on the millions of years scale this clearly doesn't matter. But there are great technological advances required, to get even a prototype reactor with regularly energy delivery running. This will probably require a few further decades. The drawbacks should be due to our current knowledge far less than with todays fission plants: a GAU like event is physically impossible and the radioactive waste should be far less in amount as in matters of radioactive decay. However, for now this is only an option for the future, and with this technique I close the evaluation of energy sources.
Now a few words about reducing the amount of consumed power: indeed there is a potential for this in highly developed countries as well as in the less well developed ones. The most important possibilities are: a great reduction of indvidually driven cars (mosty the ones with only the driver in), a ban of trucks over great distances, advances in the insulation of buildings to decrease the loss of heat and substitution of energy wasting industrial processes by more modern ones. A remark seems necessary with respect to insulation: the so-called low energy houses are not the desired goal, for the energy bilance is not as good as for very well and also cheaper insulated relatively normal buildings with the need of producing the required parts in mind. Besides, to get modern buildings very well insulated can be achieved much more easily of course.
But all of these measures cannot deny the need for great amounts of
energy in future, because the growing mankind and the also advancing development
of not top-developed countries will clearly overcompensate any trials to
reduce power needs at certain areas.
... and here is my Conclusion:
From the above to me only one way into future of energy delivery is discernable:
At the short scale: further building nuclear fission plants all over the world and in the very short future also a substitution of oil and coal with earth gas seems to be okay, for it releases only around the half amount of carbon dioxide as oil and coal does per energy unit.
In the middle timescale: disregarding all carbon burning activities (also of gas) and introduction of efficient (i.e. not todays) solar energy plants and devices.
At the longer timescale: if possible substitution of fission by nuclear fusion reactors and maintain a mix of fusion and solar energy.
Intentionally I give no exact numbers of years in which it should be accomplished, and in the far future nobody can predict what will happen. Of course, if we not survive, this has been only a theoretical discussion...
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