- Humanity may face an energy crisis as the world's population rapidly grows.
- Nuclear power plants can generate bountiful, carbon-free electricity, but their solid fuel is problematic, and aging reactors are being shut down.
- A Cold War-era liquid-fueled reactor design could transform thorium — a radioactive waste from mining — into a practically limitless energy source.
- US engineers proved such a system works during the 1960s. However, the military canceled the project and it was nearly forgotten.
- Companies and governments are now trying to revive and evolve the design, but development costs, regulations, and nuclear-weapons concerns all pose hurdles.
The lifeblood of modern civilization is affordable, free-flowing energy.
It gives us the power to heat our homes. Grow and refrigerate food. Purify water. Manufacture products. Perform organ transplants. Drive a car. Go to work. Or procrastinate from work by reading a story about the future of energy.
Today's cheap, bountiful supplies make it hard to see humanity's looming energy crisis, but it's possibly coming within our lifetimes. Our numbers will grow from 7.36 billion people today to 9 billion in 2040, an increase of 22%. Rapidly developing nations, however, will supercharge global energy consumption at more than twice that rate.
Fossil fuels could quench the planet's deep thirst for energy, but they'd be a temporary fix at best. Known reserves may dry up within a century or two. And burning up that carbon-based fuel would accelerate climate change, which is already on track to disrupt and jeopardize countless lives.
Meanwhile, renewable energy sources like wind and solar, though key parts of a solution, are not silver bullets — especially if the world is to meet a 2050 deadline set by the Paris Agreement. Energy from fusion is promising, but it's not yet proved to work, let alone on a commercial and competitive scale.
Nuclear reactors, on the other hand, fit the bill: They're dense, reliable, emit no carbon, and — contrary to bitter popular sentiment — are among the safest energy sources on earth. Today, they supply about 20% of America's energy, though by the 2040s, this share may drop to 10% as companies shut down decades-old reactors, according to a July 2016 report released by Idaho National Laboratory (INL).
The good news is that a proven solution is at hand — if we want it badly enough.
Called a molten-salt reactor, the technology was conceived during the Cold War and forgoes solid nuclear fuel for a liquid one, which it can "burn" with far greater efficiency than any power technology in existence. It also generates a small fraction of the radioactive waste that today's commercial reactors — which all rely on solid fuel — do.
And, in theory, molten-salt reactors can never melt down.
"It's reliable, it's clean, it basically does everything fossil fuel does today," Kirk Sorensen, the chief technology officer of nuclear-energy startup Flibe Energy, told Business Insider. Sorensen was speaking during an episode of Business Insider's podcast Codebreaker, which is produced with National Public Radio's "Marketplace. "
"And it does a whole bunch of things it doesn't do today, like make energy without emitting carbon," he added.
What's more, feeding a molten-salt reactor a radioactive waste from mining, called thorium (which is three to four times more abundant than uranium), can "breed" as much nuclear fuel as it burns up.
Manhattan Project scientist Alvin Weinberg calculated in 1959 that if we could somehow harvest all the thorium in the Earth's crust and use it in this way, we could power civilization for tens of billions of years.
"The technology is viable, the science has been demonstrated," Hans Gougar, a nuclear physicist at INL, told Business Insider.
Demonstrated, because government scientists built two complementary prototypes during the 1950s and '60s.
They weren't good for making nuclear weapons, though, so bureaucrats pulled funding for the revolutionary energy technology. The last working molten-salt reactor shut down in 1969.
Today, entrepreneurs such as Sorensen are working tirelessly to revive and modernize the technology. So are foreign governments like India and China.
China now spends more than $350 million a year developing its variation of the Cold War-era design.
The story of how we got here is neither short nor simple, but it explains why Sorensen and others are betting big on humanity's coming "Thorium Age" — and why the US continues to stumble at its dawn.
Image in text: W. Oelen/Wikipedia (CC-BY-SA 3.0)
The argument for nuclear energy
Its brutalist architecture may not be sexy, but nuclear energy unlocks a truly incredible source of carbon-free fuel. Ounce per ounce, uranium provides roughly 16,000 times more energy than coal and creates millions of times less pollution.
The argument to support growth in nuclear energy is so clear to James Hansen, a seasoned climatologist and outspoken environmentalist, that he passionately advocates for the use and development of the technology.
"To solve the climate problem, policy must be based on facts and not on prejudice. The climate system cares about greenhouse gas emissions — not about whether energy comes from renewable power or abundant nuclear power," Hansen and three other well-known scientists — Ken Caldeira, Kerry Emanuel, and Tom Wigley — wrote in an editorial for The Guardian in 2015.
"Nuclear energy can power whole civilizations, and produce waste streams that are trivial compared to the waste produced by fossil fuel combustion," they wrote. "Nuclear will make the difference between the world missing crucial climate targets or achieving them."
Climate science aside, the economics of nuclear energy are enough of a draw to make the technology worthwhile.