Readers of my posts here will note that I often am hostile to the notion that renewable energy will quickly be available on a scale sufficient to address the immediate catastrophe of global climate change. Consistently, I regard this faith in the "renewable only" approach as a form of denial and wishful thinking.
That said, any energy that is available from renewable means is welcome and, given the circumstances, actually in some ways
essential.
Although I don't
like dams and their impact on ecosystems, I more or less accept that all told, they are relatively clean and safe. Moreover, droughts excluded, they are more or less available on demand. They may not be truly renewable in the long term sense that reservoirs silt, but if and until we can get a handle on unrestrained human populations, it is difficult to imagine that we could dispense with the exajoule quantities of energy that hydroelectric facilities provide.
Another form of renewable energy - at least renewable for the short term - is geothermal energy. This energy of course, is not available everywhere, but where it is available it works, and is relatively benign. I note that some places and countries have huge geothermal resources that are still under utilized, Iceland comes to mind, and to the extent that they are under utilized, it is under the circumstances regrettable. Incredibly, as my friend KimIlBush, from Hawaii, over at SmirkingChimp writes, even this relatively benign form of energy is subject to NIMBY opposition that can
stop it.
http://www.smirkingchimp.com/viewtopic.php?topic=63627&forum=16 (KimIlBush, who regrettably has been ill, is from Hawaii.)
The wind industry is of course, thousands of years old. Historically its chief utility has been in pumping water but, as is well known recent advances in engineering have made a viable source of electricity that is increasingly attractively priced. Although it suffers from some (ultimately disgusting) NIMBY opposition, the fact is that wind energy is an excellent source of power, where it exists. It's chief drawback is its unpredictable nature.
Solar energy is expensive, and also subject to the vissitudes of weather, but to the extent that it can be afforded and used, it is to be encouraged, especially because it directly displaces peak gas demand, demand which is increasingly problematic. (Solar energy is also, of course, available to provide
heat for water and living space, and even, though far more rarely, process heat.)
The biofuel industry is mature, on some level of course it is
ancient, but biofuel availability is subject to the availability of water, an increasingly precious and variable commodity that is subject, especially in the age of global climate change, to extreme fluctuations and in many areas, such as the American West, outright depletion. There are other potential environmental impacts of biofuels of course, air pollution and eutrophication being two, but it is difficult to imagine that biofuels will ever be as dangerous as fossil fuels. An attractive feature of biofuels of course, whatever their limitations, is that in some cases - at least where they don't displace
rain forests as in Brazil and Asia - they actually function to
remove carbon dioxide from the air.
All this said, even as I reiterate my criticisms, as part of my ongoing attempt to educate myself about the topic of the global climate change/energy crisis, I will note that I have discovered a technology that potentially will have a big effect on my thinking about the utility and growth of renewable energy.
I am referring to George Olah's methanol fuel cells, which as I have recently learned, he says can be made
reversible. The last word is everything. Imagine that this technology were readily available. Methanol, the one carbon alcohol, is consumed in the fuel cell where combined
electrochemically with oxygen, it gives electric current, carbon dioxide and water. What is interesting is that if it is reversible, when one supplies electric current to the fuel cell, theoretically one could convert carbon dioxide back into methanol, a convenient, if toxic, liquid fuel. (The toxicity could be eliminated by converting methanol into dimethyl ether or other forms such as the formaldehyde adduct trioxane, or the mixed methanol/formaldehyde adduct dimethoxymethane - all three are directly usable in Olah's fuel cells.)
What this means, of course, is that one could
directly process excess electricity - let's say wind power that is available on a day of low electricity demand - into liquid
shippable fuels. Or one could make Iceland into a type of Saudi Arabia. Rather than attempting to ship
hydrogen, a dangerous and uneconomic proposition, made from Icelandic geothermal (and hydroelectric) electricity, one might be able to fill tankers with dimethyl ether, or in the worst case, methanol.
Such a state of affairs would go a long way toward softening one of my big criticisms of wind power, for instance, that it's energy must be
stored in order to meet on demand needs. Note that the fuel cell is not quite a battery, in as much as the fuel can be removed from the system and stored externally. It is in fact, superior to a traditional battery. One would not need billions of tons of batteries - with all the attendant environmental implications. One could simply drain fluids out of the cell and use them in a variety ways, including combustion, or as a synthetic raw material.
In the current emergency, I caution against inappropriate optimism, the tendency that is, unfortunately all too prevalent, wherein a a conception or idea is represented as a
solution. In fact a
solution is something that is already available on an industrial scale, and clearly the methanol fuel cell isn't. I still contend that we are out of time and must go with what solutions exist and are demonstrated. I note that the manufacture of these cells has not been done on scale, nor does anyone understand the drawbacks, lifetimes or efficiency. I note that the cells use platinum and ruthenium, two relatively rare metals, although in a supported form on large surface area organic supports. The supply of ruthenium can be made much larger by isolating it from fission products, but platinum is definitely in limited supply. Platinum is, of course, routinely recycled. There is a long, long, long way between here and there.
One example of Olah's fuel cell work is described in US patent 6,821,659.
It is exciting and interesting work, and one would hope that its potential will be fully explored.
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