Saturday, August 26, 2006

Energy: So you want to replace oil?

This is a very very long rant about energy, and my attempt to provide my perspective on the issue. Energy really is of central importance to our society, and entrusting our energy futures to pie-in-the-sky dreams, conspiracy theories, witchhunts and political pandering is not in our best interests. Getting a good perspective on this issue is a task requiring some analysis of the actual degree of scale that we're talking about, thermodynamics, and the actual efficacy of different methods of power production. If the public became better informed (I mean really informed, not just subscribing to the latest "alternative" energy fad), it would then force politicians to stop playing public-perception games and obstructing the development of sound enegy sources.

Energy: What You’re Up Against When You Talk About Getting Rid of Oil
So, you want to free America from its “oil dependence”? You think conservation, or fuel efficiency is the key to becoming self sufficient? After all, we’re “dependent on energy”, and we really shouldn’t consume so much, right? Idealized, primitive (thouroughly oppressed) peasants in their rice paddies don’t consume anywhere near the energy that we do. But then again, primitive peasants don’t produce most of the world’s wealth, or enjoy much of it, do they? The modern industrialized lifestyle exists because we have found ways of getting machines to do our work for us. Machines don’t do work for us when they don’t have an energy source. Per capita wealth is directly proportional to per capita productivity. Per capita productivity is proportional to the amount of machines we have working for us, the extent to which they work for us, hence the amount of per capita power we have available. If we were to suddenly stop consuming energy one day, then that would be it for civilization as we know it: Back to scratching the dirt with a stick hoping to glean enough off of the land using primitive farming techniques to feed yourself (or enslaving your neighbors to do so, which is probably more likely). No fertilizers, backhoes, or even pumped irrigation, and you can forget about transporting produce long distance. A life without energy is a life of medieval grinding poverty (and serfdom to those who still have the use of energy and industry).


So no, civilization should not free itself from its “energy dependence”!! Civilization is dependent on energy exactly as much as the body is dependent on oxygen. Without it, there is no hope of using our resources or doing work to anywhere near the extent that we can do today.

1. Efficiency

So, one canard down, what about “efficiency?”. Surely there are ways we can improve the efficiency of our processes so that we don’t need to consume energy at the rate that we do? There is room for improvement in efficiency to a limited extent. But it also depends on what sort of efficiency you’re after. Do you want efficiency, as in consumes less energy (usually what is meant)? Do you want ease of manufacture? Do you want the product to be efficient to design and maintain? These different sorts of efficiencies are often in conflict. Economic efficiency means providing you the product at the least cost and overall effort. Energy efficiency often requires more complicated, difficult to manufacture devices. Furthermore, efficiency is a sharp diminishing return game. It’s impossible to be more than 100% efficient. It’s thermodynamically impossible to be more efficient than the devices Carnot efficiency. For diesel engines, we’re at about 34-40. For large power stations, we’re at 40-60%. (Cengel, Bois, Thermodynamics, 254). As you approach these barriers, the convolution and cost of your device approaches infinity. The ideal efficiency, the ceiling at which you thermodynamically cannot operate above, no matter how convoluted your diesel engine gets, is between 60-70%. (Cengel, 464, a function of the compression ratio btw).

Theoretically, assuming we could pack a device that somehow managed this 60% efficiency in a truck, which could then get this efficiency under real world conditions, we would be able to reduce our oil consumption from 7.3 billion barrels a year to something like 5.8 billion (we use something like 70% of our oil for automotive purposes. We use the rest for heating and electricity production). That could save us some time, as far as total oil supplies go, but it extends our oil-driven lifespan (whatever it turns out to be) by only 25%. That is the most we can expect out of increasing our efficiency. It’s not going to free us from foreign oil. The only thing that will free us from foreign oil dependence is actually developing our domestic oil supplies.

2. Notes on how much oil is left:

The world consumes oil at somewhere around 50 million barrels/day. There are 836 billion barrels estimated in our proven reserves. (Source: http://www.infoplease.com/ipa/A0922041.html)
Proven reserves mean conventionally extractable, readily refinable oil (of the right characteristics) that has been discovered and mapped out. It doesn’t mean that that is how much total oil there is. There are unconventional oil deposits (such as shale oil) which require unconventional extraction methods (which are currently being developed by our oil industry). http://www.radford.edu/~wkovarik/oil/ These reserves can be as high as 2 trillion barrels not counting the Venezualan Orinoco heavy oil belt (which may contain an addition 1-4 trillion barrels). So, proven reserves are going to run out in 50 years at present consumption rates, assuming both a continuation of present consumption levels (unlikely – they’re probably going to increase exponentially as they have throughout history) and assuming that no new proven reserves will be discovered (also very unlikely – the ocean coasts are probably lousy with unexplored oil as the recent events in the gulf and Alaska demonstrate). We could have anywhere from 50-200+ years of oil left, depending on the playout of many unforeseeable factors.

Nevertheless, it is going to run out someday. Furthermore, the use of all conventional oil supplies is likely to cause some significant discomfort. Shale oil, and other harder to mine deposits, though present in larger quantities, are also more difficult and expensive to mine. Another note – eventually the process of extracting the oil takes more energy than you would get out of the finished gasoline. Contrary to popular belief, this isn’t an impassible barrier by any means. You just need to use a non-oil energy source to drive the extraction process. (My favorite, for reasons I’ll go into in future posts, is nuclear).

So rather than running dry instantly, the following scenario is likely to play out. Assuming 100% social flexibility (ie. The government will let the oil companies do what needs to be done to get at these deposits, which, given the popular mindset of environmental self-flagellation is far from given), oil companies will attempt to mine ever more difficult deposits of oil. The easiest ones to get at (and hence the cheapest) will obviously go first. After that, harder and harder deposits will be mined. (These more difficult deposits, fortunately exist in larger quantity). Gasoline will continue to get more and more expensive, as harder deposits are mined. Eventually the gradually increasing prices will drive us to a different energy source. We’ll never run out of oil, we’ll just have to stop using it as our primary energy source at some point.

3. We need a SOURCE

We need an energy source. This one central fact of civilization will not go away as long as civilization exists. You have an enormous stake in making sure it continues to exist. We cannot loftily abstain. We cannot make ourselves more and more efficient until we cease to require sustenance. I’m certainly not going to tolerate a sub-industrial lifestyle, no matter what you may prefer, and I’m willing to fight for it, so you can count out placating people like me into passive sacrifice.

An energy source is distinct from an energy transport or storage mechanism. Hydrogen will not power our civilization. It may power our cars, but it is not a source. It is a proposed storage method. Hydrogen doesn’t sit around in pools in the ground like oil does, in a naturally elevated chemical energy state. We have to produce it, and to do so, we have to expend energy. Another example of a transport mechanism, as opposed to a source, is a battery. It is charged with energy generated elsewhere.

We’re making progress on our storage methods all the time. Our batteries are at about 15% the energy density of gasoline by mass. http://hypertextbook.com/facts/2003/ArthurGolnik.shtml. I don’t have the source, but I was reading something the other day about a boron-hydride fuel cell that uses boron hydrides (far easier to work with than LH2 or compressed hydrogen btw) to get 1/5 the energy density of gasoline within the fuel cell unit.

But what is going to drive this process? We’re talking about replacing 7.3 billion barrels of oil/year. That’s 6.1E9 J/barrel (http://www.eppo.go.th/ref/UNIT-OIL.html). That’s 1.4E12W of energy. That’s assuming there aren’t any inefficiencies in converting the driving energy into these equivalent fuels. 1400 GW. 1,400,000 MW. 1000 Hoover Dams!!

0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home