07/25/2012 - 05:57

Water, climate, and thorium: Why nuclear power makes sense for South Africa

Participants in this Roundtable are asked whether, given the dangers that climate change presents, nuclear energy is worth the risk for developing nations. My own country, South Africa, offers a particularly interesting lens through which to examine this question.

South Africa is best known internationally as the one-time home of apartheid. Not as well known is that during the apartheid era, as South Africa became an international pariah, the country's decision-making elites responded to perceived threats to national survival by encouraging the development of sophisticated capabilities in science, engineering, and technology. One manifestation of this was a nuclear weapons program.

During its transition to democracy South Africa abolished its nuclear weapons program and, in 1991, acceded to the Nuclear Non-Proliferation Treaty. Thus it became the world's first nuclear-armed country to voluntarily relinquish its weapons. This fact alone places South Africa in a unique position from which to reflect on questions of nuclear proliferation and nuclear energy.

In want of water. Today, the greatest threat to South Africa's survival, and certainly to its prospects for prosperity, may be water scarcity -- a problem that, as will be explained, is closely connected to climate change.

South Africa is among the 40 driest countries on earth. Its location between three global weather systems -- the intertropical convergence zone, the Southern Ocean, and the El Niño-Southern Oscillation -- helps account for the nation's annual average rainfall of only 495 millimeters (mm), compared to a global average of 860 mm. So severe are South Africa's water challenges that a national economy only exists because, through hydraulic engineering projects, rivers have been pushed around on a national scale.

Complicating matters, the majority of the country's economic activity takes place in the hinterland, on a high and dry central plateau. Johannesburg, which is the economic capital not only of the country but of continental Africa, is the world's largest city not located on a river, lake, or seashore. At about 1,800 metres above sea level, it straddles the continental divide that separates the Orange and Limpopo River Basins.

The Orange and the Limpopo, which drain into the Atlantic and Indian Oceans respectively, are crucial to the nation's economy -- but only a small percentage of the rain that falls across the country is converted into water in these rivers. The conversion rate in the Orange River Basin, for example, is a meager 3.4 percent. This means that, of 100 units of water that fall as rain across the surface of the basin, only 3.4 units become water in the river and thus become useful for industrial purposes. The rest is lost to evapotranspiration. Climate change will likely cause low conversion rates to fall even further as losses to evapotranspiration increase.

South Africa has attempted to address its chronic water shortage through dam construction, but dam-building is reaching its limits. In the Orange River Basin, total dam storage capacity is already equal to a staggering 271 percent of the annual average flow of the river. To put it another way, almost three times as much water is stored in dams on the Orange River as would flow through the river, undammed, over an average annual cycle. This is indicative of water constraints that call into question South Africa's viability both as a stable democracy and as a nation capable of providing full employment for all.

Hotter, drier. Climate change, with its new and largely ill-defined risks, threatens to make matters worse. Increases in the ambient temperatures in South African river basins will exacerbate evaporative losses and disrupt weather patterns that are already unpredictable. And as ambient temperatures increase in areas that are stressed to begin with, the country's problem with excessive nutrient flows is likely to worsen -- already, about one-third of South Africa's available water is highly eutrophic (that is, rich in dissolved minerals and thus supportive of excessive life, most notably blue-green algae).

As a professional in the water sector who is deeply involved in strategic planning processes, I see no viable future for South Africa unless we develop a sophisticated recycling ethos. Today, national water resources that are available at a high assurance of supply amount to about 38 billion cubic meters annually. This number needs to increase to about 65 billion by 2025 if we are to achieve full employment (assuming that the water-use patterns on which employment depends do not become more efficient). This means that South Africa will either have to gain access each year to an additional 27 billion cubic meters of water from rivers to which we have no legal riparian claim (the Zambezi or the Congo) -- or we will have to use our total national resources about 1.7 times each year. But such recycling in effect implies desalination, because excessive mineral salts and endocrine-disrupting chemicals must be removed. This, in turn, requires massive amounts of energy.

South Africa's current energy platform, which is centered on coal combustion, is clearly unsustainable. But nuclear energy would be another story -- especially if South Africa were to construct nuclear power plants using thorium as a fuel. Indeed, South Africa is ideally positioned to utilize thorium-based power reactors. First, the country has large reserves of thorium, which is currently regarded as a waste mineral with few commercial uses. Second, South Africa occupies a moral high ground in nuclear affairs by virtue of having relinquished its weapons program, and thus it would make an appropriate candidate to help pioneer the use of thorium, a fuel with enhanced proliferation resistance. It should also be mentioned that South Africa is among the relatively few developing countries that already utilize nuclear energy, and does not lack for technical capacity in this sector.

South Africa's future will be dictated in large measure by the way the country addresses its water scarcity dilemma, and by its ability to create employment amid growing resource constraints. Extensive changes will be necessary if the country's challenges are to be met. Because the hinterland happens to be located on a high plateau, massive amounts of energy are required to pump water uphill to reach it; eventually, major industries will likely have to relocate to the coast. In all probability, desalination of seawater will become the hydraulic foundation of the nation's economy, and this suggests a greater potential role for nuclear energy.

South Africa enjoys an abundance of both uranium and thorium. But it is the latter resource that could provide the country the relatively clean energy it needs for economic development without introducing new proliferation risks.