Finding A Way Through
Posted in Unfounded Speculation
on December 29th, 2009 by
Stephen DeGrace
Topics:
Crystal Ball
There is simply no way to avoid a massive human die-off in the coming century without maintaining a high-energy technological civilization. In the long run, of course, human survival with any semblance of a decent standard of living depends on there being a lot less humans. Nine billion human beings is simply too great a strain on the earth's carrying capacity for us to get away with it for very long (and that's making the possibly unfounded assumption that we can get away with it at all). But we would like to get to a sustainable place the painless way, by having less babies and waiting for the old folks to die off on their own. Since that is likely a tall order, we need to be thinking very seriously about how we're going to manage the relatively short term of the next fifty or a hundred years or so.
The key requirement is clear: cheap, super-abundant energy. Massive food production consumes a massive amount of energy, and we will need to produce food on a more massive scale than has ever been done before. Assuming anyone has any food to export by mid-century, inexpensive transportation to make food imports affordable to nations badly hit by global warming will be crucial, and of course, nations will need to transport food internally at significant expense. Desalinization of sea water may be the only realistic source of water for some highly-populated arid nations which are rapidly consuming their sources of fossil water (*cough*Saudi Arabia*cough*). Every aspect of the very pleasant lifestyle we in the industrialized world enjoy and which everyone in the developing world has a right to aspire towards requires access to cheap, abundant energy.
Certainly, conservation and advances in efficiency will play a key role, but with rapid development in a number of key, heavily-populated countries such as India and China plus continuing growth in the overall world population, conservation cannot take up all the slack. The picture is further complicated by peak oil and the need to eliminate greenhouse gas emissions.
Sustainable Fossil Fuels
We could last a long time if we could go on burning fossil fuels without worrying about global warming. Which is why the fossil fuel industry has decided the global warming is a myth, and is busy funding a massive misinformation campaign to get to public to buy that story. The manufacture of synthetic crude from tar sands or coal is expensive compared to pumping increasingly scarce light, sweet crude right out of the ground. However, if it were the only realistic option, I have no doubt that the combination of overwhelming economic incentive and scientific knowhow would bring the price right down, making "dirty" fossil fuels a credible alternative to maintain our technological civilization possibly for a couple hundred years at least. This could give us ample breathing room (well, not necessarily "breathing" room, but you get the idea) to develop alternatives for the even more long-term survival of our civilization.
The only slight problem with that is if our carbon emissions are limited to conventional oil we're pretty much screwed enough as far as the climate goes, but if we then decide to burn every last scrap of coal in the ground, we're dead for sure. 100% guaranteed. Unless we can get carbon capture and storage to work in a feasible way. The technology to capture carbon dioxide in an economical way already exists, or at least that's the theory - there are a number of claims to that effect out there, anyway, from inventors who are thus far playing their cards close. But in any case, it does seem reasonable that human ingenuity should be up to that task of finding a reasonably economical way to capture carbon dioxide, even directly from the atmosphere, so that we don't have to worry about capturing it at every source. Not having to capture carbon at the tailpipe of every car is an important requirement. Perhaps the capture devices could even be wind powered. The problem with CCS is always the storage.
Some have suggested piping liquid carbon dioxide into the deep oceans on the grounds that the CO2 in the air would "get there anyway." Personally, I think I would be far and away from being an "environmentalist spoil-sport," but absolutely I think that any country attempting that form of storage is grounds for war, nuclear war if that's what it takes to stop them. Yeah, massively acidifying the whole ocean from the bottom up, that couldn't have any consequences. Especially if it were done really rapidly, over a couple centuries or so, and if we basically transferred the entire carbon content of every coal seam and oil deposit in the world into the ocean. And certainly we wouldn't have to worry about the carbon dioxide escaping into the atmosphere when the deep water rises to the surface again - surely science would have magically found a way to make the problem go away by then!
Whatever. It seems like the only non-terracidally-reckless option for storage is underground, in formations with proven capacity to trap gases, or in saline aquifers. If we put our CO2 in such formations, it will definitely be back courtesy of plate tectonics, but that's pushing the problem way into the future, and volcanoes naturally belch out carbon dioxide anyway, coming from subducted carbonates. It remains to be seen whether such storage methods can be made economical, are truly secure, or can be made to scale to the necessary level, given that if the consequence of CCS is permanent burning of fossil hydrocarbons into the foreseeable future, that's a lot of carbon dioxide that will need to be stored.
CCS is worth studying, but it offers no guarantees, and the danger is that if it proves to be a dead end, it may offer us an excuse to stay hooked on fossil fuels for longer than we can really afford. The other danger is that since it lets us go on doing what we're doing, more or less, without upsetting a lot of applecarts, it will actively encourage the suppression of alternatives as long as it is taken seriously. That said, if nothing else pans out in time CCS might be necessary to save us, so it can't be ignored, either.
Alternatives
The key energy coinage is electricity. If you have a cheap way to generate a huge amount of electricity, you've basically solved our energy problem. Cars and trains can be made to run on electricity (but to move our whole transportation infrastructure to electricity would require a massive increase over the current capacity). Aviation might not be directly possible with anything like the scale and convenience of what we now enjoy on electricity alone (I can't say it would be impossible to have an electric plane, because you might be able to create an ultra-light and very tiny prop plane that ran on electricity), but with abundant enough electricity you could even manufacture jet fuel from carbon dioxide and hydrogen and maintain some semblance of the aviation industry.
The key thing is that you need a way to generate base load. Electricity basically needs to be generated on-demand, at the same time as it is used. This sets a fundamental limit on how much electricity you can take from intermittent sources like wind. Wind can become an important part of our energy mix, but the more wind, the harder it is to manage the grid. A modern super-grid of high voltage DC cables connecting wind farms over a huge geographical area might average out some of this variability, but you still need an on-demand source. Massive adoption of nuclear power might be one option. but it has its own pollution concerns. Nothing matches the convenience of fossil-fuel-burning generation in the grid to generate base load, but we need to find something that does.
Practically every alternative basically amounts to solar power (actually, since the energy in fossil fuels was ultimately captured by organisms from the sun, it too is like a form of stored solar power). Hydroelectric (the water cycle depends on solar energy to evaporate water) is great for those with access to it, but far too limited in its potential. Wind, another sun-driven energy source, has the intermittency problem. It's really hard to see how photovoltaics could really bridge the whole gap... focusing solar energy to heat water and drive a turbine seems more promising. An enormous amount of power could be generated reliably during the day in the world's deserts and transported over a modern supergrid, but there is that pesky night problem to consider (this could be mitigated with some sort of storage scheme, perhaps). While biofuels on arable land are a terrible idea in a world where food supplies are very tight, possibly the development of biofuels such as oil-rich algae raised in brine would be a way to generate actual, carbon-neutral hydrocarbons for direct burning. In this way, sunlight could be captured in an economical and convenient form for use on demand.
Abundant enough solar power could even be used to hydrolyze water to generate hydrogen, if the technologies for a viable hydrogen economy ever come through, or used to make synthetic hydrocarbons from carbon dioxide and hydrogen. This could conceivably allow solar power to be stored in a form which could be used for transport or on-demand power generation. All of this is very hypothetical, however.
Energy that doesn't come from the sun is interesting. Pretty much all of it comes from nuclear reactions, either fission or fusion (solar energy itself, and all its derivatives, falls into the natural fusion category, by the way). Conventional nuclear power is an interesting example of a realistic way to generate a lot of electricity. On the con side, it draws on a finite resource, uranium, and has serious environmental issues in terms of waste disposal. But, it does not emit CO2, except indirectly from the uranium mining, and we will need to keep it on the table as an option.
Geothermal energy is a sort of indirect fission power, as the interior of the earth is heated by decay of radioactive isotopes which are naturally present. Too bad the number of good sites is limited, but it can be a great local option.
Nuclear fusion right here on earth is in theory the most awesome energy source ever: clean, cheap and basically infinite. Unfortunately, the technical challenges are immense and even its proponents talk about its practical availability in terms of being decades away. While in theory it's clean, in practice some forms generate radioactive waste from neutrons emitted by the fusion reaction striking the reactor shielding, which is expensive and made from limited resources and then has to be disposed of in lengthy downtime.
Then there's the magnetic shielding. The most promising forms of nuclear fusion depend on immensely powerful magnetic fields to heat and confine the plasma in which the fusion reactions take place. These fields are generated with superconducting magnets, which, unless high temperature superconductors which can be cooled with liquid nitrogen ever unexpectedly become available and practical, need to be cooled with liquid helium.
Helium does not naturally stay in our atmosphere, because it is too light for the Earth's gravity to hold. Helium that we use on Earth, for practical things like MRI or NMR or gas chromatography or for retarded things like helium balloons, is in a real sense actually a fossil fuel, strangely enough. Helium gets generated on earth through radioactive decay of many radioactive isotopes - an alpha particle is just a helium atom minus the electrons. This helium builds up in the earth, and at certain suitable locations may become dissolved in oil at significant concentrations, where it becomes available to humans as a by-product of oil extraction. Much of the helium on earth actually comes from oil fields in Texas, which are rapidly depleting, creating our present helium shortage and high helium prices. This sounds like a joke to a lot of people, because they don't realize just how serious the lack of helium is for a lot of important uses the public doesn't generally know about. But good luck basing a future civilization on the availability of massive amounts of cheap helium, which is what most fusion schemes currently on the go basically require.
I think fusion is great and we should definitely throw massive amounts of money into researching it. It may never pan out, but if it did it would be like winning the lottery for human civilization. But, just like the real lottery, don't make your plans based on it 
.
There isn't a lot of energy out there that doesn't come ultimately from a nuclear source - the only one I can think of off-hand is the limited niche source of tidal energy, which works by capturing some of the kinetic energy in the earth-moon system.
Conclusions
In terms of the future of energy, all that can really be said for sure is that we can't continue as we have been. Even if we try, peak oil will force us to bend our ingenuity to making less desirable hydrocarbons like bitumen and coal more economical, which will almost certainly create a major drag on our economy, but can certainly keep us going a while longer. At least until such time, not nearly far enough into the future for anyone's comfort, that our civilization will finally choke to death on its own pollution, most probably through the devastating destabilization caused by global warming.
Every way out that leads to long-term survival involves undeveloped and/or unproven technologies. So it is obvious what we must do - we must invest heavily into research and development through institutions of higher learning, and we must harness the power of the free market by artificially attaching a high price to carbon dioxide emissions on a global scale. Only by making resources available to our best minds and creating powerful incentives can we really have any hope that something will pan out in time. If we don't take this path, it will take more than a miracle to save us.
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