I recently read a very interesting article on the topic of oil exploration and consumption; on world energy use in general really. While I did not agree with some of the statements the author made, the main thrust of the article was spot on and sobering. Regardless of whether it happens tomorrow, twenty years from now or two hundred years from now, we are living on borrowed time. Our present technological civilization depends on large quantities of cheap electrical power. For the most part, this is produced by finite resources; resources we have been rapidly consuming. When they are gone, they are gone. Then what?
Regardless of our political leanings, what we would like to believe, and how we would like the world to be, “finite” means finite, not “unlimited”. Yes, technological advances allow us to access oil in locations where we couldn’t years ago. Yes, extraction techniques have improved, allowing us to get more out of formations than in the past. But these techniques are increasingly expensive and energy intensive in and of themselves.
When it gets to the point where it requires as much or more energy to obtain the resource as the resource will provide, then it will be a moot point whether or not we have truly run out of oil; the effect will be the same. This is true for coal and natural gas as well. It may take a while, but eventually all will end up at the same place.
It may not take as long as people think. If energy usage were constant, then yes, we would have enough for quite some time; at least for those of us fortunate enough to live here in the United States. And whereas most folks do express sympathy for those in the world less fortunate whose standard of living is way below what we enjoy here, few are all that eager to give up what we have to join them.
But energy usage is not constant. Not only is our population growing (the 2010 census is expected to show the population of the United States to be over 309 million people), but world population is growing (currently estimated to be 6.8 billion people). And many of those folks are no longer willing to live in grass or mud huts; industrialization worldwide is sharply increasing, resulting in an ever increasing demand for electricity to power everything, just as it does here in the United States.
So where will all the energy come from?
This is where it gets interesting. We currently power most everything from oil and natural gas not because greedy oil companies have made us dependent on it, but because it is the most portable, energy-dense, and economical energy source around. A barrel of oil produces a known quantity of electricity. It isn’t variable like solar or wind, which may or may not be there when you need it. Modern industrial society requires a stable baseline power supply. Coal, oil and natural gas supply that need very nicely.
To be sure, there are other stable sources. From simple water wheels powering mills of various types to hydroelectric power harnessed by dams, the power inherent in the movement of water from a higher location to a lower location is one of the oldest power sources used by man. But as enormous as some of our hydroelectric projects are, and some like Hoover Dam, or the Three Gorges project in China, or the High Aswan Dam in Egypt are truly enormous, they provide but a fraction of the electrical power we need.
Hydroelectric production is not without limit either, as folks in Venezuela are discovering. Dams are only as good as the water stored behind them. Long periods of drought can wreak havoc with electrical production, particularly if the water behind the dam is also used for other purposes such as irrigation and municipal water supplies.
What about nuclear? Long a “dirty word” in the political landscape, nuclear is making a comeback as oil, coal, and natural gas prices increase and interest in reducing “green house gasses” becomes a hot topic. In fact, even though no new nuclear plant has been ordered since 1978, and no U.S. reactor has been completed since 1996 (a reactor actually ordered in 1970), nuclear power today is responsible for 20% of the electricity generated in the United States. The power is produced in 103 licensed power reactors operated at 65 plant sites in 31 states.
In a report for Congress, it was noted that as of 2007, US nuclear power production has grown steadily, up more than 20%, despite no new plants being built. Much of this increase is due to reduced downtime which has resulted from shorter refueling outages. This has enabled nuclear plants to increase the amount of electricity they generate from about 65% of total capacity in the mid 1980’s to 89.8% of total capacity in 2006.
The result is that the amount of power generated by nuclear plants in the U.S. today exceeds the electricity generated from oil, natural gas, and hydro electric plants, trailing only coal in total production. In 2006, nuclear plants generated a near record 823 billion kilowatt-hours of electricity. This is more than the nation’s entire electrical output in the early 1960s and more than twice the 2005 total electrical generation of Great Britain.
Which also points out just exactly how much electrical power usage has grown in the last 45 years in the United States alone.
So how much uranium is there in the world to power our nuclear reactors? Well, like oil, we are not the only country that operates nuclear reactors. And unlike the United States, other nations are still actively building them. The result is that worldwide, there are currently more than 400 nuclear power plants now in operation, providing more than 17% of the globally produced electricity. In some countries, such as France, nearly 80% of the electricity generated comes from nuclear power. There are currently some 25 or so new reactors on order or being built worldwide.
This does not include nuclear reactors on naval vessels, of which over 150 have been built.
Uranium is a fairly common element, being approximately as common as tin or germanium in the Earth’s crust. As a comparison, this is around 35 times more common than silver. Unfortunately, most of this uranium is spread out, being present in most rocks, dirt and in the oceans; concentrations of uranium, necessary for mining are much rarer. It is estimated that the amount of uranium which is economically recoverable (at the current price of $130/kg) is sufficient to last at least 100 years at the current rate of consumption. If the price were to double from current levels, deposits with lower concentrations would become economically feasible to mine, increasing the amount available approximately tenfold. At high enough prices, eventually extraction from sources such as granite and seawater would become economically feasible.
There is a lot of available uranium. Ultimately, like oil, gas, and coal, it is a finite resource. But there is enough to tide us over for quite a while until other energy sources can be found. And unlike oil, coal, or natural gas, there is every reason to expect that uranium exists in other places in this solar system besides the Earth. Eventually perhaps, those resources can be tapped as well.
There are also ways to stretch the available nuclear fuel. The nuclear technology currently being used is very inefficient. Much time and expense is taken to enrich the naturally occurring uranium isotope U-238 to the more uncommon but easier to fission isotope U-235. Current light water reactors only fission the U-235. Not only that, but only a small amount of the U-235 is actually used before the fuel rods are removed from the reactor and stored.
We could greatly increase the availability of nuclear fuel (and decrease the amount of “waste” we need to store) if we were to reprocess the “spent” fuel rods instead of storing them. Reprocessing can recover up to 95% of the remaining uranium and plutonium in the “spent” fuel rod, and reduces the volume of the remaining waste by over 90%.
Reprocessing is done in various countries in the world, notably Europe, Russia, Japan, and India. It was banned in the United States in 1976, because of fear of nuclear weapons proliferation. President Reagan lifted the ban in 1981, however to date no nuclear reprocessing is taking place in the United States.
Another technology for nuclear reactors is the fast breeder reactor. Unlike light water reactors, fast breeder reactors use the more common U-238 isotope. How common is U-238? 99.3% of all naturally occurring uranium is U-238. Estimates are that there is enough U-238 available to power these types of reactors for up to five billion years. While still a finite resource, this is enough to, at least at this time, be effectively infinite!
So why don’t we just convert everything over to fast breeder reactors then? A nearly limitless source of energy, and no “greenhouse gas” emissions to worry about? Sweet!
Well, it turns out that fast breeder reactors are more expensive to build and operate than conventional light water reactors. Reprocessing the fuel safely is a high-cost operation. Like with most power technologies, the cheaper ones are used first. So as long as there is an availability of cheap off-the-shelf uranium to power light water reactors, fast breeder technology, requiring uranium costs in the $200/kg range, will continue to languish. We need to use up the cheap, easily mined stuff first.
Additionally, fast breeder reactors produce plutonium, which can be used to make nuclear weapons. (Note: it can also be used as nuclear fuel in power plants as well.) This adds the proliferation concerns as well. Still, other countries have build breeder reactors. Japan for example, is basing the future of their nuclear power industry on fast breeder technology.
And by no means is this the only way to produce electricity from nuclear fuel. Although uranium is the best known radioactive element it is not the only one that can be used in a nuclear fuel cycle. Thorium, also a radioactive element, can be used as well. The thorium fuel cycle is a little different than the uranium fuel cycle, but reactors using thorium have been built. India, which has a lot of thorium available, has built several. There are advantages and disadvantages to thorium plants. If you are interested, take a look at the link above.
One advantage is that the Earth’s crust contains about 3.5 times more thorium than uranium. This would extend the total practical fissionable resource base by 450%. The sun will explode before all the available thorium and uranium here on Earth are exhausted! So while technically speaking uranium and thorium are not “renewable” resources, practically speaking they are pretty much inexhaustible, at least based on current and projected energy use.
The biggest drawbacks so far are cost and waste storage. And of course, the potential for a catastrophic accident, such as happened at Chernobyl. Can these be overcome? I believe so. As the cost of fossil fuels increases due to scarcity, the cost of nuclear technology will by comparison become more “reasonable.” Advances in nuclear technology will help mitigate, if not solve the waste storage/disposal issue. Advances in technology will also make nuclear reactors safer to operate. The next generation of nuclear technology, known as “Generation IV” reactors, is currently under development.
Fossil fuel technologies, nuclear technology, and to the extent that sufficient water resources are available, hydroelectric power all meet the criteria for producing a stable, known base load of power on a 24x7 basis. In the next article we will take a look at other electrical production technologies to study their suitability for replacing oil, gas, and coal as the primary generators of our nation’s electrical needs.