If I said to you that there is a source of energy that is abundant in the earth, cannot be made into a weapon, cannot melt down in a reactor, and emits no greenhouse gases, it would sound as though we had a nearly perfect source. Well, what I’ll describe here is not perfect, but it may be another step in our journey to the ultimate source of energy. –Gregg Braden
You’ve never heard of thorium? Well, neither had I before I read Gregg Braden’s book, The Turning Point: Creating Resilience in a Time of Extremes.
Natural gas is plentiful, for now, and at least it is a cleaner fuel than coal or oil. Braden calls it a “stepping stone,” a source of energy that we can use for now until we find cleaner, safer, cheaper sources. Wind, hydroelectric and solar power are the cleanest, but may not be able to furnish all our energy needs, globally. So-called “free energy” may be possible someday, but not right now. Nuclear energy looked promising, but it is downright dangerous. Just think of Chernobyl, Three Mile Island, or Fukushima. What else is there?
Thorium is a radioactive element, atomic number 90 on the periodic table. It was discovered in 1828 by the Norwegian mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius. They named it after Thor, the Norse god of thunder. There’s a little thorium in most rocks and soils; it’s about as common as lead, twice as abundant as uranium. However, it has to be separated from the rock through a complex, multi-stage process. Most thorium is extracted from monazite. There are thought to be concentrations of thorium in India, the United States, Australia, Canada, South Africa, Brazil, and Malaysia, in particular. It’s hard to tell exactly where the concentrations are because up to now, there has been very little demand for it.
One gram of thorium is more energy dense than 7,396 gallons of gasoline. Eight grams of this substance could power a thorium turbine motor vehicle for a century. (That’s, of course, if you had such a vehicle and you could afford that much thorium.) When used in a Molton Salt Reactor (MSR) , one ton of thorium produces the same energy as 250 tons of uranium. 99% of thorium fuel is actually consumed, versus 1% for uranium. Thorium by-products can also be used as fuel. Thorium power costs approximately $1.98/watt versus $2.30/watt for coal. Thorium works differently from uranium, and it cannot melt down because of its chemical properties. It produces no weapons-grade by-products.
So far so good. It sounds perfect, but of course, there are some concerns. In certain forms, thorium is highly combustible and can ignite spontaneously. Then, of course, there is the fact of its radioactivity. It’s half-life is the age of universe! We really have no idea what effect it might have on human beings, animals, or the environment. Startup costs are high, although once you have a reactor going, it can be used to start other reactors.
Canada, China, Germany, India, the Netherands, the United Kingdom, and the United States have all experimented with using thorium as a nuclear fuel. Now that we are running out of coal and oil and there is so much resistance to using tar sands, now that natural gas is so abundant, and now that we know uranium is just too unsafe to use in nuclear reactors, there is a lot of interest in thorium. Just the other day I saw an article online that said China was “going for broke” to build thorium reactors. Keep your eye out for other stories about thorium in the coming months.
Meanwhile, I still think we need to expand wind and solar power and keep searching for ways to tap into that mysterious “free energy” the science geeks are always talking about. 🙂