The Long Descent (4 page)

If access to oil supplies was the point of America's recent Middle East entanglements, the results have not been worth the cost in money, lives, and international prestige. The Afghanistan and Iraq invasions put American troops in control of the world's last remaining major undeveloped oil fields. In both cases, however, American military power drove a hostile government from power but proved unable to make peace in their absence, much less secure access to oil reserves. Moreover, these military adventures have pushed America into exactly the sort of imperial overstretch that Paul Kennedy warned about in his widely respected book
The
Rise and Fall of the Great Powers.

Meanwhile, the energy, materials, and time expended on these ventures were desperately needed to help make the transition to a post-peak economy. One of the central themes of
The Limits to
Growth
was precisely that modern civilization cannot turn on a dime. Changing from one energy resource to another isn't simply a matter of pouring something different into our gas tanks, because much of today's energy infrastructure is fuel-specific — that is, you can't burn coal in a nuclear reactor or dispense hydrogen through a gasoline pump. It took 150 years and some of the biggest investments in history to build the industrial, economic, and human infrastructure that turns petroleum from black goo in the ground to the key power source of modern society. To replace all that infrastructure with a new system designed to run on some other form of energy would take roughly the same level of investment, as well as a great deal of time.

In a widely cited 2005 study, a team of researchers headed by Robert Hirsch determined that even given the full resources of the US government, a program to head off the worst consequences of peak oil would have to be launched fully twenty years before peak to keep the inevitable production declines from having severe impacts on economy and society.
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The problem here is that we don't have twenty years. We probably don't have ten. We may not have five. As I write these words, world petroleum production appears to have peaked in late 2005 and declined since then, despite sky-high prices that make even the most marginal oil wells paying propositions. Several more years will need to pass before it's clear whether those declines are a temporary fluke or the beginning of the end of the Petroleum Age, but it's possible that peak oil has already arrived.

Replacing Petroleum?

The obvious solution to the peak oil problem is to find something to replace oil, and this became a third major topic for discussions within the peak oil community as soon as the scale of the problem became clear. The problem peak oil researchers found, as their equivalents in the 1970s discovered before them, is that replacing oil with anything else is much more difficult than it looks. Sheer volume poses the first of many difficulties. The world burns 84 million barrels of petroleum — more than three and a half billion gallons — every single day, with about a quarter of that going to the United States. Replacing even a small fraction of that vast flood of energy and material from any other source poses staggering challenges.

To start with, the three other fuels that, together with oil, provide most of the world's energy — coal, natural gas, and uranium — are already being exploited at a breakneck pace. Official statements about reserves of these resources suffer from the same distortions as oil, for similar reasons, and statements that there will be plenty of these fuels for many years to come need to be assessed with this in mind. These sanguine estimates also fail to take into account what would happen if production has to be increased in order to make up for dwindling supplies of oil.

As things stand today, uranium reserves are severely depleted worldwide (roughly half of the reactor fuel used today comes from dismantled Russian warheads, not from mines) and prices have soared accordingly in recent years.
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Unless huge new reserves turn up unexpectedly, the supply of reactor fuel will start to fall short of demand sometime before 2010 — in other words, around the same time oil does. Natural gas is expected to hit its worldwide Hubbert peak around ten years after oil, and North American natural gas production will most likely begin dropping before that. Furthermore, a growing fraction of Canadian gas now gets burned to power the plants that extract oil from Alberta's tar sands, which decreases the amount of gas available for other uses and accelerates the depletion rate.

The one fossil fuel we can expect to have left in large quantities after oil peaks is coal, the most abundant of all the fossil fuels — and also the dirtiest. For many years, claims that the world had virtually endless supplies of coal have been part of conventional wisdom, but recent studies have cast serious doubts on that comforting faith; the National Academy of Sciences, for example, has issued a report warning that current estimates of the amount of coal left in the United States are wildly inflated.
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Furthermore, unlike oil or natural gas, coal's energy content varies dramatically from one variety to another. Anthracite, the most energy-rich grade of coal, contains about half the energy as the same weight of petroleum, while lignite, the lowest grade, contains as little as a sixth.
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Sensibly enough, mining firms have concentrated on extracting the best grades of coal first, and so most of what's left is low- grade “brown coal” full of sulfur and other impurities. In recent years the ratio between the amount of energy provided by coal and the amount of energy needed to mine it has been dropping rapidly — so rapidly, according to some studies, that by 2040 coal will take about twice as much energy to mine as it produces when burned.

The problems with coal are a good example of the crucial problem of
net energy,
the least discussed and most challenging part of the energy equation. To get energy out of any resource, you have to put energy in. To access the energy in oil, for example, you have to invest the energy needed to drill and maintain an oil well. The energy you get out minus the energy you put in equals the net energy of the resource. Net energy varies from one fuel to another, and it also varies from one source to another — oil from a newly drilled well producing light sweet crude under natural pressure can have a net energy of 200 or more (that is, burning the oil yields 200 or more times as much energy as it takes to drill and maintain the well). On the other hand, oil from an old well that has to be pumped out of the ground often has net energy down in single digits.

A net energy of 1 is the breakeven point — the resource yields exactly as much energy as went into extracting it — and many of the proposed “solutions” to the energy crisis have lower net energy than that. This makes them energy sinks, not energy sources. Hydrogen, the “wonder fuel” ballyhooed by so many pundits in recent years, could be the poster child for this particular problem because there are no reserves of hydrogen gas lying around waiting for us to tap into them — not this side of the planet Jupiter, anyway. Pure hydrogen must be manufactured from water or natural gas, and you have to put slightly more energy into extracting it from these sources than you will get back from burning it; the result is negative net energy. Trying to run an economy on energy sources with negative net energy is like trying to support yourself by buying $1 bills for $2 each. No matter how you calculate it, it's a losing proposition.

More insidious is the fact that all other fuels and energy resources receive a hidden “energy subsidy” from oil. For example, coal is excavated and transported by machinery powered by petroleum-derived diesel fuel, not by coal. Coal contains much less energy than oil does. As mentioned earlier, it takes about twice as much coal as oil to do the same amount of work, even with anthracite, and if you're burning brown coal it takes much more. If coal has to be mined, processed, and shipped using machinery powered by coal or a coal-derived diesel substitute, costs soar and efficiencies slump by at least a factor of two. Of course, if you have to turn the coal into a liquid fuel, or build new mining machinery to run on coal, the energy needed for either process also has to be factored into the equation. If oil prices itself out of the market, in other words, coal reserves have to be drawn down much faster just to maintain current levels of coal production. Try to replace oil with coal, using coal-powered technology to do the mining, and seemingly huge coal reserves run out rapidly.

If other fossil fuels and conventional nuclear power can't take up the slack, what about exotic technologies such as breeder reactors and nuclear fusion? There has been a great deal of hype about these high-tech methods, but a flotilla of challenges still has to be met before any of them contributes even a single kilowatt to the electricity grid. Most of the handful of breeder reactors built around the world in the last few decades have been shut down due to massive technical problems. Fusion has never even gotten that far despite billions of dollars in research funds. Only Nature has been able to construct a working fusion reactor that actually produces energy in useable amounts.
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Even if one or more of these technologies could be made to work, retooling the modern energy economy to make use of them would demand immense and increasingly scarce amounts of money, resources, and time. Proponents of these exotic technologies have never addressed — much less answered — the question of how much
net
energy could be produced.

All of this leaves only renewable resources such as solar power, wind, and biofuels to supply our energy. Some of these have net energies in the single figures, others are close to breakeven, and still others fall well below the breakeven point, making them useless once the energy subsidy from oil runs out. Those that yield positive net energy have a valuable part to play in the world's energy future, but crippling problems of scale make it impossible to replace more than a small fraction of fossil fuels with renewable energy. It's worth taking a moment to see how this works.

Let's imagine, for example, that the United States decided to replace its current gasoline consumption (a large sector of its fossil fuel use, though not the largest) with ethanol derived from corn. The United States uses about 146 billion gallons of gasoline a year; since ethanol only yields three-quarters as much energy per gallon as gasoline, it would take a bit over 194 billion gallons of ethanol to keep the present American automobile fleet on the road for a year. According to US government figures, there are about 302 million acres of arable land in the United States; corn yields about 146 bushels an acre on average, and you can get 2.5 gallons of pure ethanol out of a bushel of corn.
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This means that if every square inch of American farmland were put to work filling our gas tanks — with none left over to grow food or anything else — the total yield of ethanol would only be a little over 110 billion gallons, which is just a bit more than half of our current gasoline consumption.

Still, this is only the first half of the equation, because oil has more net energy than ethanol. Drilling for oil is relatively cheap in energy terms, and refining it from crude oil uses 5% or less of the energy value of the crude oil it comes from.
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By contrast, it takes a great deal of energy to produce 146 bushels of corn an acre, and it takes a good deal more to process and ferment the corn on an industrial scale. The exact energy costs to grow corn and turn it into ethanol vary widely depending on details as complex as the terrain of farmland, the sugar content of the variety of corn, and the amount of rainfall in the months prior to harvest. It's possible to provide this additional energy in different ways, too — in terms of growing costs, for example, you can divert a large share of the ethanol to power tractors and combines, or you can divert a large share of the corn to feed horses and farmhands — but one way or another, you have to factor in the extra energy needed to get from seed and soil to ethanol fuel. Even if all the arable land in the United States were devoted to replacing gasoline consumption, the amount of energy produced would fall drastically short of current needs.

The same thing is true of every other form of renewable energy. Today, the world gets much of its energy supply almost free of charge by drilling a hole in the ground and piping the results somewhere. Getting the same amount of energy in any other way requires much more energy to be fed back into the energy production process. Nowhere does the energy subsidy for cheap oil have a greater effect than on renewables. Making a solar cell, for instance, requires large infusions of diesel fuel first to mine the raw materials and then to ship them to the factory. Even larger doses of natural gas or coal are needed to generate the electricity that powers the complex process of turning the raw materials into a cell that will make electricity out of sunlight. The complexity of the process makes net energy calculations challenging, but estimates range from a very optimistic 10:1 yield to more pessimistic, and arguably more realistic, 1:1 net energy yield.
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Not even the most optimistic calculations show solar cells yielding anything in the same ballpark as the net energy routinely produced by all but the poorest fossil fuels. The same, as it turns out, is true of every other alternative resource.

Fossil fuels are so much more valuable than other energy resources because they get a double energy subsidy from Nature herself. The first half of the subsidy arrived in the prehistoric past via photosynthesis, the process by which plants absorb and concentrate solar energy. All the fossil fuels, in energy terms, are stored sunlight heaped up over geologic time long before our ancestors strayed out of the shrinking tropical forests of the late Pliocene and launched themselves on the trajectory that led to us. No human being had to put a single day's work or a single gallon of diesel fuel into growing the tree ferns of the Carboniferous period that turned into Pennsylvanian coal beds, nor did they have to raise the Jurassic sea life that became the oil fields of Texas.