Warming up to nuclear power

WHEN I TELL my “green� friends that I am rethinking nuclear power, they respond with outrage. I am an environmentalist, and, to a large extent, the green movements in the developed world arose from public concern about atomic energy.

For about 30 years we have seen nuclear power as dangerous, its radioactive wastes as unmanageable, the industry as incompetent and untrustworthy. In the environmental camp, any softening of this opposition is seen as a betrayal.

But climate change and falling energy reserves demand that we reopen the question. The nuclear industry now claims that nuclear power is the most reliable answer to the global warming caused by the overuse of fossil fuels. It argues that new technologies make it safe and cheap.

I’ve spent the last year searching for a way to cut carbon emissions by 90%, which is necessary to prevent runaway global warming. One of the hardest problems is how to generate enough electricity. My sympathies lie with renewable power. Alongside a massive energy-efficiency program, it plainly provides part of the answer. But it cannot supply all of our electricity needs. The rest must come from somewhere, and to dismiss nuclear power without considering what the alternatives involve would be irresponsible.

I still detest the nuclear industry and its efforts to hoodwink the public about its costs, its dangers and its record. But I’ve reluctantly concluded that some of its arguments have merit.

It is true, for example, that a disaster on the scale of Chernobyl is highly unlikely to happen again because no new power station will be built without a containment vessel, which prevents most radiation from escaping in an accident. But the mining, processing and use of uranium will continue to be accompanied -- as they always have been -- by leaks into the environment.

It now looks as though radioactive waste can be stored safely. The Finnish authority responsible for nuclear waste disposal has developed a method that looks foolproof. The problem is that it is expensive, and the nuclear industry has a long record of cutting corners. One British company was caught throwing nuclear waste into open shafts it had dug above crumbling coastal cliffs. Another admitted that it had been keeping plutonium in uncovered ponds for more than 30 years. Workers at the U.S. Geological Survey, which is responsible for testing the Yucca Mountain waste repository in Nevada, falsified the rates of water percolation, apparently to make the site seem safer than it is.

After reading reams of conflicting data, I now also believe that global supplies of uranium are not the limiting factor many feared. On the other hand, the threat of nuclear terrorism can never be wholly dismissed, and the more fissile materials that are extracted and refined, the more opportunities there will be for people to obtain them. But although the radiation released by accidents or terrorists could kill hundreds or perhaps thousands of people, climate change caused by burning fossil fuels threatens hundreds of millions.

Though nuclear power is plainly less dangerous than climate change, I would still like to avoid building new plants if possible. But the real danger is this: If we oppose nuclear power without demonstrating that there are viable alternatives, we become, in effect, lobbyists for the coal industry. In Eurasia, there are still abundant supplies of natural gas, but in North America, gas production has already peaked and is in long-term decline. Already, coal supplies 32% of U.S. electricity, while natural gas supplies 24% and nuclear power 10%. As 90% of remaining U.S. fossil energy reserves take the form of coal, gas generators are likely to be replaced by coal plants. The same applies to aging nuclear generators, if they are not replaced by new ones.

If you believe that burning coal sounds more benign than nuclear power, I invite you to turn on your computer and search for images of the “mountaintop removal� being carried out by coal-mining companies in the Appalachians. It looks as if a nuclear disaster already has happened. The forests have been flattened, the hilltops blown off, the valleys filled with sterile rubble. Coal is also the worst of all fuels as far as climate change is concerned. It contains 40% more carbon per unit of energy than gas.

But if fossil fuels and nuclear power are bad choices, could 90% of the electricity in the United States be generated by greener means? There is no doubt that, if it could be harnessed, the U.S. has enough ambient energy to provide all the electricity it now uses. Amory Lovins of the Rocky Mountain Institute points out that the wind in a few counties in the Dakotas is, in theory, sufficient to supply the entire nation with electricity. Though no one is suggesting that all U.S. energy should be drawn from one source, the development of cheap, high-voltage direct current, or DC, lines of the kind now used in Brazil, Sweden and Australia would permit even the most remote sources to be exploited. The problem with transporting power has been that the electricity load carried by traditional alternating current, or AC, systems declines as the distance increases. But DC systems don’t suffer such “line losses.� In principle, DC lines could open up wind and wave power across the entire U.S. continental shelf, and solar electricity throughout its deserts.

What about the cost? Although estimates vary widely, electricity from large-scale wind farms appears to be cheaper than electricity from either nuclear power or coal, and its costs are falling fast. Even solar thermal electricity, a more expensive technology than wind, is now cost-effective in some places. A report published last year showed that during times of peak demand in Southern California, the cost of electricity produced by solar thermal plants is roughly equal to the wholesale price of conventional power. Peak demand in sunny places, driven by air-conditioning, coincides with maximum solar output.

The problem with alternative energies is that the coincidence of demand and supply is by no means guaranteed. Power companies can fire up their standby coal plant when demand rises, but they can’t turn on the wind or ask the sun to shine. This problem can be partly overcome by using long-distance DC cables: When there’s a flat calm in New York, there could be a gale blowing in Chicago. The wider the net from which electricity can be drawn, the more reliable ambient power becomes. But beyond a certain point -- perhaps 50% or so of total supply -- power from intermittent sources cannot be guaranteed. Part of the remainder could be supplied by burning biomass such as straw or wood. But farm waste is limited, and mass planting of fuel crops has implications for water tables and the global food supply.

So, with gas growing scarcer, where do Americans find the rest of their power? It seems to me that the U.S. has only two choices: either to build a new generation of nuclear plants or to find a genuinely acceptable, nonpolluting means of mining and burning coal.

Such a means might exist, if underground coal gasification fulfills its early promise. In principle, you can partly combust underground coal seams, capture the gas they produce and scrub the pollutants from it, producing either methane or hydrogen. The methane can be burned in power stations and the carbon dioxide in their exhausts extracted and buried, reducing greenhouse gas emissions by about 90%. The hydrogen could be piped to people’s homes and used in mini-generators to provide both electricity and heat. But unless great care is taken, underground combustion could contaminate supplies of groundwater.

Picking “clean coal� or nuclear power is not a choice I would like to make. But if there is one thing I have learned in studying our energy systems, it is that there are no painless solutions.