This is not an insignificant amount of electricity. If we covered every rooftop in the county with solar collectors, we could probably power our indoor lighting plus some basic household appliances – during the daytime. Solar’s great advantage is that it peaks exactly when it is needed, during hot summer afternoons when air conditioning pushes electrical consumption to its annual peaks. Meeting these peaks is a perennial problem for utilities and solar electricity can play a significant role in meeting the demand. The problem arises when solar enthusiasts try to claim solar power can provide base load power for an industrial society. There is no technology for storing commercial quantities of electricity. Until something is developed – which seems unlikely – wind and solar can serve only as intermittent, unpredictable resources.
There is only so much energy we can draw from renewable sources. They are limited, either by the velocities attained, or by the distance that solar energy must travel to reach the earth. So is there anyplace in nature where we can take advantage of that “c2” co-efficient and tap transformations of matter into energy? There is one that we have used through history. It is called “chemistry.”
Chemical energy is commonly described in terms of “valences.” A sodium atom has a valence of +1, meaning it is missing an electron in its outer shell. Meanwhile, a chlorine atom has a valence of –1, meaning it has an extra electron. Together they “mate” to form sodium chloride (table salt). All chemical reactions are either “endothermic” or “exothermic,” meaning energy is either absorbed or released in the process. The Bunsen burner in chemistry class is a way of adding energy to a reaction. The other thing that can happen occasionally in chemistry lab is a sudden release of energy called an “explosion.”
The great achievement of 20th century quantum physics has been to describe chemical reactions in terms of E = mc2.
When we burn a gallon of gasoline,
one-billionth of the mass of the gasoline is completely transformed into energy. This transformation occurs in the electron shells. The amount is so small that nobody has ever been able to measure it. Yet the energy release is large enough to propel a 2000-pound automobile for 30 miles – a remarkable feat when you think of it.
Still, electrons make up only 0.01 percent of the mass of an atom. The other 99.99 percent is in the nucleus of the atom. And so the question arose, would it be possible to tap the much greater amount of energy stored in the nucleus the way we tap the energy in the electrons through chemistry?
For a long time many scientists doubted it could be done. Einstein himself was skeptical, saying that splitting an atom would be like “trying to hunt birds at night in a country where there aren’t many birds.” But other pioneering scientists – Enrico Fermi, George Gamov, Lise Meitner and Leo Szilard – discovered it could be done. By the late 1930s it had become clear that energy in unprecedented quantity could be obtained by splitting the unstable uranium atom.Unfortunately, World War II pre-empted the introduction of nuclear power. This is a historical tragedy. The atom bomb stands in the same relation to nuclear energy as gunpowder stands to fire. While gunpowder has played an important role in history, fire’s role has been far more essential. Would we want to give up fire just because it led to guns? Yet the atom bomb continues to cast a shadow over the equally important discovery of nuclear energy.
The release of energy from splitting a uranium atom turns out to be 2 million times greater than breaking the carbon-hydrogen bond in coal, oil or wood. Compared to all the forms of energy ever employed by humanity, nuclear power is off the scale. Wind has less than 1/10th the energy density of wood, wood half the density of coal and coal half the density of octane. Altogether they differ by a factor of about 50. Nuclear has 2 million times the energy density of gasoline. It is hard to fathom this in light of our previous experience. Yet our energy future largely depends on grasping the significance of this differential.
One elementary source of comparison is to consider what it takes to refuel a coal plant as opposed to a nuclear reactor. A 1000-MW coal plant – our standard candle - is fed by a 110-car “unit train” arriving at the plant every 30 hours – 300 times a year. Each individual coal car weighs 100 tons and produces 20 minutes of electricity. We are currently straining the capacity of the railroad system moving all this coal around the country. (In China, it has completely broken down.)
A nuclear reactor, on the other hand, refuels when a fleet of six tractor-trailers arrives at the plant with a load of fuel rods
once every eighteen months. The fuel rods are only mildly radioactive and can be handled with gloves. They will sit in the reactor for five years. After those five years, about six ounces of matter will be completely transformed into energy. Yet because of the power of E = mc2, the metamorphosis of six ounces of matter will be enough to power the city of San Francisco for five years.
This is what people finds hard to grasp. It is almost beyond our comprehension. How can we run an entire city for five years on six ounces of matter with almost no environmental impact? It all seems so incomprehensible that we make up problems in order to make things seem normal again. A reactor is a bomb waiting to go off. The waste lasts forever, what will we ever do with it? There is something sinister about drawing power from the nucleus of the atom. The technology is beyond human capabilities.
But the technology is not beyond human capabilities. Nor is there anything sinister about nuclear power. It is just beyond anything we ever imagined before the beginning of the 20th century. In the opening years of the 21st century, it is time to start imagining it.
William Tucker is the author, most recently, of Terrestrial Energy: How Nuclear Power Will Lead the Green Revolution and End America’s Energy Odyssey.