Laurence Smith - The World in 2050 - Four Forces Shaping Civilization's Northern Future

Public health remains the single greatest concern with nuclear energy. Although great strides have been made to increase reactor safety, 147accidents and terrorism remain legitimate threats. Of grave concern is the disposal of radioactive waste, which must be safely interred for tens of thousands of years. The most feasible way to do this is probably subterranean burial in a geologically secure formation. But certifying anything as “geologically secure” for a hundred thousand years is exceedingly difficult. After more than two decades of research and $8 billion spent, the U.S. government recently killed plans to tunnel a long-term nuclear waste repository into Yucca Mountain, a volcanic formation in Nevada. Even in the middle of desert, there was simply too much evidence of fluctuating water tables, earthquakes, and potential volcanic activity to declare the site “safe” for a hundred thousand years.

Finally, there is the issue of fuel supply. Estimated R/P life-index estimates for conventional uranium are under a hundred years, with most closer to fifty years. Therefore, over the long run a shift to nuclear power will require the reprocessing of spent uranium fuel rods from conventional “once-through” nuclear reactors so as to recycle usable fissile material. But spent-fuel reprocessing yields high-grade plutonium, even small amounts of which are the principal barrier to acquiring a nuclear bomb. Therefore, any expansion in nuclear power that involves spent-fuel reprocessing or breeder reactors elevates the threat of proliferating nuclear weapons and creates attractive targets for terrorism.

Nuclear power generates about 15% of the world’s electricity today. In a recent analysis of the industry’s future, the Massachusetts Institute of Technology concluded that if aggressive steps are taken to deal with the issues of waste disposal and security, it is feasible to more than triple the world’s current capacity to 1,000-1,500 conventional “once-through” nuclear reactors, up from the equivalent of 366 such reactors today. 148Enough natural uranium is available to support this to at least midcentury or so. Depending on the choices we make, 149our global nuclear power capacity is projected to either stagnate or grow fivefold, producing as little as 8% to as much as 38% of the world’s electricity by the year 2050.

Besides nuclear fission, there are only three other carbon-free sources of energy positioned to significantly dent the world’s power needs by 2050. 150Unlike nuclear energy (which consumes uranium), they are truly renewable. One of them, hydropower, is already important, generating about 16% of the world’s electricity today. The other two sources—wind and solar—provide barely 1% combined. But that breakdown is poised to change.

Hydropower is a mature technology that has already been developed to or near its maximum potential in much of the world. There are only so many large rivers, and even fewer appropriate places to build a dam. Except in Africa, South America, and parts of Asia, most of the good spots have already been taken. Big dams also create many local problems. They pool huge reservoirs, displacing farmland, wildlife, and people. They dramatically change hydrological conditions downstream—a big source of strife between countries sharing transboundary rivers—and fill up with silt, requiring dredging. While “small hydropower” schemes that don’t require dams, like waterwheels, have great potential for growth, big dam projects do not. For this reason, regardless of the choices we make, 151hydropower is expected to lose market share despite doubling in absolute terms. By 2050, it is projected to supply just 9%-14% of the world’s electricity.

Wind and solar, in contrast, are the fastest-growing energy sectors today. Although wind power provides barely 1% of the world’s electricity, that number hides enormous differences around the globe. Nearly 4% of electricity in the European Union, and nearly 20% in Denmark and the Canadian province of Prince Edward Island, comes from wind. 152This has partly to do with geography—the mid to high latitudes are windier than the tropics, for example—but much of it is driven by investment.

The wind power trend kicked off in the 1980s in California and in the 1990s in Denmark. Today, Germany, the United States, and Spain are aggressive wind developers and presently lead the world in total installed power capacity, each with fifteen thousand megawatts or more (a typical coal-fired power plant is five hundred to a thousand megawatts; a thousand megawatts might power one million homes). India and China are close behind with six to eight thousand megawatts. Canada, Denmark, Italy, Japan, the Netherlands, Portugal, and the United Kingdom all have installed capacities of one thousand megawatts or more. Altogether, at least forty countries worldwide are now developing wind farms, 153and all of these numbers are growing quickly.

The reasons for this rapid growth are many. To start, wind is free. Wind turbines are relatively cheap, consume no fuel or water, emit no greenhouse gases, and, aside from the permitting process, can be installed quickly. Because wind farms are comprised of many turbines, it is possible to start small, then grow capacity over time. At present, wind power is one of the cheapest renewable energies, averaging around $0.05 per kilowatt-hour, 154putting it closest to conventional fossil-fuel electricity prices ($0.02-$0.03/ kWh). The main concerns with wind power are bird and bat deaths, conflicts over land use, and aesthetics. Most wind farms today are on land, but offshore installations are also gathering investors’ interest. While it’s harder to install turbines and grid connections in the ocean, offshore winds are stronger, so they produce more electricity, and there is less competition for the space. In 2010 the Obama administration approved the United States’ first offshore wind farm near Cape Cod, Massachusetts.

The wind power industry has a thirty-year legacy and is now reaping double-digit growth. Depending on the choices we make, 155our global wind power capacity is expected to grow anywhere from tenfold to over fiftyfold by the year 2050, cornering 2%-17% of the world’s electricity market.

That leaves solar energy. The Sun, in principle, offers us more inexhaustible clean power than we could ever possibly use. One hour of sunlight striking our planet contains more energy than all of humanity uses in a year. It absolutely dwarfs all other possible energy sources, even if we add up all of the world’s coal, oil, natural gas, uranium, hydropower, wind, and photosynthesis combined. It is nonpolluting, carbonless, and free. Panels of solar photovoltaic cells have been powering satellites for over half a century, and we see their familiar shape all around us—encrusted on streetlights, garden lamps, and pocket calculators. Why, then, is our total world production of solar photovoltaic electricity equivalent to that of just one very large coal-fired power plant?

For all its largesse, sunlight has a fundamental problem. Although vast in total, its energy density is low. Unlike a power-packed coal nugget, sunlight is diffuse, low-grade stuff. Getting significant power out of it requires covering a large area, either with mirrors to focus the Sun’s rays, or with panels of photovoltaic (PV) cells that directly convert solar photons into electricity. Both are expensive (especially photovoltaics) and efficiencies are low.

Theoretically, 156PV cells can convert sunlight to electricity with efficiencies as high as 31%, but most are considerably lower, around 10%-20%. If that sounds pathetic to you, then consider that the efficiency of plant photosynthesis, after three billion years of evolution, is just 1%. Nonetheless, a typical silicon-based solar photovoltaic panel, with 10% efficiency and a manufacturing cost of around three hundred dollars per square meter, produces electricity that costs around thirty-five cents per kilowatt-hour. That’s seven to seventeen times greater than coal-fired electricity. So sunlight, despite being far and away the world’s biggest energy source, is also the most expensive.