Coal can be dirty. Natural gas is fraught with security and supply problems. So what’s left to make our light bulbs glow? How about the atom?

Granted, the threat of nuclear calamity hasn’t ceased to exist. But these days it’s less unsettling — and less pressing — than catastrophic climate change. All of which leads to a new nuclear equation: If it has risks, they’re worth running — a sentiment which has prompted climate- and energy-focused governments to take another look at nuclear power.

Atomic energy is remarkably clean, with reactor plants emitting no carbon dioxide. The simple fact is that only two energy sources offer base-load generating capacity: coal and nuclear. This will likely remain true for quite a while. Since many agree that coal is simply too dirty, nuclear power becomes a singular resource: the only technology capable of meeting our growing demand for energy while keeping emissions down.

A bright upshot is that nuclear energy is relatively cheap — and will only get cheaper as other energy sources become more expensive with the likely establishment of a carbon emissions tax. As far as security and availability are concerned, atomic energy is a good deal. The raw material for nuclear fuel, uranium ore, is abundantly available through friendly, Western-oriented countries such as Australia. With regards to safety, the nuclear industry’s record has been nearly spot-free since the Chernobyl incident in 1986. No big accidents resulting in deaths; only close calls —thanks mostly to better design and improved safety standards.

Many American energy analysts have ceased focusing on which technology will prevail. The real question is how quickly the country can become energy independent while simultaneously maintaining economic growth and causing little environmental impact. Do we need more energy from solar, wind, hydro and other renewable sources or from clean coal and natural gas? Yes. But, so the argument goes, we also need the energy nuclear can provide — and more of it.

More is possible

Though nuclear power already makes up a significant portion of world energy, a great deal more is possible. Nearly 450 operating reactors produce 16 percent of all electricity generated worldwide. In the U.S., over 100 plants generate 20 percent. But in France a whopping 85 percent of electricity comes from the atom, showing just how much more energy is available if the technology is more fully embraced.

In the United States, Sens. John Kerry and Barbara Boxer have introduced an energy bill that advocates such an embrace. Granted, it’s more modest than some would like, but it clearly accepts the notion that more reactors are a viable low-emission power boost. And as a piece of legislation, it has a bright future, with Republicans long-itching to go nuclear.

Already, utilities and nuclear power companies have filed 17 applications for 26 new reactors and the U.S. Nuclear Regulatory Commission (NRC) expects applications for five more reactors before year’s end. Worldwide, though, most of the 40 reactors now under construction are in Russia and Asia — with many of the latter in China. But reactor construction is also under way in Latin America, the Middle East and Africa. New reactors currently proposed or in progress (the IAEA estimates some 70 new plants in 15 years) would more than double the capacity of the 436 now in operation.

Still, plenty stands in the way of a full nuclear renaissance. Nuclear development is often faced with a lack of political and popular support. Both are essential. The $5 billion to $7 billion cost of a plant’s construction is too heavy a burden for nuclear power companies to bear without the prop of people and government.

But even though they’re expensive to build — demanding copious amounts of both financial and political capital — they are incredibly cheap to maintain. And cheap maintenance costs could help companies burdened by new carbon taxes offset some of that cost by diversifying into nuclear energy. In fact, revenue from nuclear power may prove so plenteous that nuclear-invested companies could end up paying windfall profits taxes, providing more cost offsets.

The greatest problem

But a certain stigma and fear are still attached to nuclear energy; and the public fears Chernobyl-like accidents and terrorist attacks. The greatest practical problem, however, is waste storage. The long-term risks of storing radioactive waste have not yet been adequately solved. Spent nuclear fuel remains dangerous for thousands of years, though it can be isolated in solid state and managed safely on a relatively small scale.

But no nuclear-powered nation has, so far, constructed a permanent geological repository for high-level nuclear waste. And this year President Obama effectively killed the closest (though admittedly problematic) thing to a solution-level repository in the U.S. by ending funding for the Yucca Mountain storage facility in his 2010 budget request.

High-level waste is not the only concern. Reactors also emit low-level waste, which poses its own disposal and storage problems. It is less dangerous but much more plentiful. And it still must be disposed of carefully. While a number of promising technologies are in development, no real “solution” currently exists.

There is also a looming shortage of qualified nuclear engineers after what was essentially a three-decade hiatus in new plant construction, which saw the emigration of lots of American nuclear construction infrastructure to Europe and Asia. In fact, the biggest challenges to really scaling-up nuclear energy in America are workforce and infrastructure related.

Nuclear energy remains uniquely viable for developing countries. Governments in these nations can take advantage of the otherwise unfortunate fact of their authoritarian nature to push through reactor construction and other aspects of a coherent nuclear development strategy that might be opposed in more democratic countries.

The basic truth is that in order to meet growing demand, the U.S. electric power industry needs to invest between $750 billion and $1 trillion in new generating capacity, new transmission and distribution infrastructure, and environmental controls over the next decade. And there is a good argument putting much of that money into nuclear energy expansion since there’s essentially no doubt atomic energy can produce a plentiful and reliable energy situation — a situation capable of supporting, for example, a vast fleet of electric cars.