Six billion is just a start

January 2000

Six billion is just a start

How can the world sustain its growing population? One key is energy technology
Last October 12 marked the day that the world’s population hit the six billion mark. Actually, no one knows when the six billionth person arrived on the scene—that date was simply designated as such by the United Nations. One thing is for certain: Six billion will not be the high-water mark for the number of people on this planet.
ORNL’s John Sheffield cites estimates that the population could be double that—12 billion—in 100 years. Moreover, in the developing world growth rates are high and, even assuming a steady slowdown in the growth rate, the developing world’s population is projected to increase from 4.7 to about 10 billion people by 2100.
“Developing” nations are sometimes also referred to as the Third World, or “emerging” nations located primarily in Asia and Africa. The “developed” world refers to the industrialized nations.

In a sustainable future, there cannot be permanent growth both in population and in the use of nonrenewable energies and other resources

“In the developed world the population is more or less stable at 1.3 billion,” Sheffield says. “Some of the more affluent countries, such as Italy and Spain, and some countries undergoing traumatic transitions, such as Russia, have an average birth rate less than the replacement rate—about two children per woman.
United Nations statistics show that the population growth rate in the developing world is decreasing while per capita energy use is increasing—which indicates an increasing standard of living. That raises an obvious question: With the most commonly used energy resources, which are key to economic wealth, in finite supply, how will these increased billions of people be able to raise their standard of living, which means they will also increase their energy consumption?
“Clearly, in a sustainable future, there cannot be a permanent growth both in population and in the use of nonrenewable energies and other resources,” says Sheffield, who directs the Joint Institute for Energy and the Environment at the University of Tennessee.
“An excellent book by Joel Cohen, How Many People Can the Earth Support, points out that with increasing standard of living, from the lowest levels, come more extensive education, increasing literacy, more rapid availability of information, greater availability and use of contraception, more opportunities for women, and a greater life expectancy,” Sheffield says. “Per capita energy use is a good indicator because energy use enables improvements in the standard of living.”
The upshot of that, Sheffield says, is that population growth tends to decrease, not increase, when the standard of living rises.
The affluent nations, the United States being the most notable example, are also the most prodigious consumers of energy. The developed countries’ 1.3 billion use about 5 tonnes of oil equivalent of energy per year (toe/a) per person. The developing world’s 4.7 billion use only 0.6 toe/a.
Studies Sheffield cites show that, with efficient energy use and in a warm climate, hitting the 1 toe/a mark per person seems to be an important, if minimal, milestone toward prosperity. However, as developing nations become more prosperous and use more energy, logic dictates that they will compete with the developed nations for ever dwindling energy resources. Or else entire regions will be condemned to poverty, which could very well breed instability and conflict.
Sheffield says it doesn’t necessarily have to be that way. The Earth can sustain a growing population that could be as high as double that of today’s. The obvious keys, he suggests, are improvements in energy efficiency and a broader energy supply base.
“Developing a means to use energy efficiently is an essential part of finding a solution to the world’s energy needs,” he says. “Today, a relatively low percentage of raw energy ends up doing useful work, such as moving a vehicle, heating a building or making a product.
“For a passenger car, for example, typically only 10 percent of the oil’s energy actually moves the car. Of that, only about two percent actually moves the passenger!”
With more efficient technologies, the developed countries could halve their per capita energy use while sustaining or even raising standards of living. In parallel, the developing countries could more readily improve their standard of living, with similar efficiency improvements and access to current low-cost energy sources
Otherwise, he warns, the world could proceed dangerously toward a more pronounced trend of haves versus have-nots.
Sheffield notes that, on all fronts, energy efficiency gains could provide a more stable and sustainable standard of living and population for the future—buildings with better insulation and more efficient appliances, more efficient agriculture and forestry, fuel cell and advanced diesel powered cars and trucks, more advanced energy recovery processes in industry and more efficient power stations. He points out that ORNL contributes to all of these areas, and to the development of improved energy sources.
Broadening the base of energy sources is important because the world is currently overdependent on fossil fuels—coal, gas and oil.
“The problem is not that the world lacks fossil fuel resources—there is more fossil energy in the United States than there is in oil in the Middle East,” he says. “The two problems are pollution from the use of these fuels and their uneven distribution, which can lead to conflict between the haves and the have-nots.
“For this reason, when the world’s annual energy use doubles or triples over the next century, it will be important to have other energy resources available to complement fossil fuels and reduce the percentage of energy they supply from the present level of around 80 percent. Renewable and nuclear energy are the additional resources that need to be expanded.” He cites some examples.

Biomass energy accounts for more than 10 percent of renewable energy use today, and it could quadruple if aggressively pursued. Half could come from agricultural wastes and forestry residues, farm animal wastes and landfills, and half from dedicated energy crops.
”Geothermal energy has important niche possibilities in certain countries,” Sheffield says, “especially as an energy source for heat pumps.”
Hydropower delivers about two percent of world energy and that could be doubled. Despite concerns about submerging land, effects on species and eventual silting, water-generated electricity is an important resource for the developing world.
Numerous options exist for capturing solar energy. “It is difficult to set a level for the potential of solar power since, in principle, it could provide all of our energy needs if developments lower the cost sufficiently,” he says. Energy from the sun is an especially promising option in arid or warm climates, where many of the developing nations reside. Solar electricity for lighting, water pumping and refrigeration is already cost competitive in remote areas with no electricity grid. Costs are decreasing rapidly. Solar water heating is widely used in some countries.
The wind power potential is huge,” Sheffield says, “even allowing for restrictions on land use.” Total capacity today is about 10 gigawatts and it has been increasing at about 20 percent per year. It is cost competitive under favorable wind conditions. As with solar electricity, its viability depends on the weather and must either be coupled to a storage system or contribute less than about 20 percent of grid power. Denmark plans to raise its wind electricity production from the current five percent to as much as 50 percent in the future, he says.
Nuclear energy is an important contributor to world electricity production, providing more than six percent of world energy use. Although public concerns are limiting its growth, that could change as fossil use is limited by environmental concerns and technology renders it more acceptable. “It will be important to resolve these public acceptance issues before fission energy can be used at a more massive level,” Sheffield says.
The development of fusion power requires a lot more R&D,” says Sheffield. “It is unlikely that it could be deployed, at the present development rate, before the middle of this century, but it has advantages over fission in safety, waste disposal and proliferation.” Although still technically in the future, “the most likely initiators of the fusion era,” Sheffield says, “are countries that are using substantial fission power, plan more, have inadequate energy supplies of their own and have the technical capability—like Japan.”

"Without more energy-efficient technologies, the world could proceed dangerously toward a more pronounced trend of haves versus have-nots."

Some of these new technologies lie out in the future. Sheffield believes, however, that the time to develop them is now. Populations are large and growing fast in the regions of the world that will have the hardest time obtaining the energy resources to raise their standard of living, and stabilize their populations. Those trouble areas are mainly in Africa, East Asia and South Asia.
"If the dependence on energy use per capita is a fair measure of standard of living, these regions need to raise their energy use rapidly enough to stabilize the populations before their energy needs become out of reach,” he says.
“Fossil fuels are carrying us toward that sustainable goal, but sooner or later other energy resources are going to have to play a bigger role, and new, energy efficient technologies will be hugely important in supporting the transition. So will the underpinning role of the science and technology that are undertaken at laboratories such as ORNL.”
In the last of the Showcase lecture series at ORNL—“the major sustainable energy lab in the country”—Sheffield asked the audience: “What if you could double the efficiency of energy use by the year 2100? Is that possible?
“Absolutely possible.”—B.C.

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