Energy needs and sources for global human prosperity

The Case for Nuclear Power

by Matthew Formby

Sastry Sreepada is a professor in practice of the nuclear engineering and engineering physics program at Rensselaer Polytechnic Institute. He has managed reactor thermal hydraulic development for the naval nuclear propulsions program at Knolls Atomic Power Laboratory, where he held several technical, managerial and advisory positions over numerous years. He has also worked on the design and development of Heavy Water Reactor, Light Water Reactor, and Fast Reactor concepts.

While concern for global warming grows, and nuclear power may be considered for it's clean base load energy there's another, equally pressing need to consider. Compared to all major fuel sources, nuclear offers the only long term potential past about 85 years. This comes from an analysis of energy use and oil, coal, natural gas, and nuclear fuel supplies made by Dr. Sastry Sreepada, of Rensselaer Polytechnic Institute. The review specifically looks at constant population values and the projected consumption of the U.S., China, India, and Brazil with U.S. energy consumption as a reference for growing demand.

Figure 1

F Vanek, L Albright, and L Angenent. (2012) Energy Systems Engineering: Evaluation and Implementation, 2nd Ed., McGraw-Hill.

Per capita GDP is known to depend upon the per capita energy usage as shown in figure 1.⁽¹⁾ For a nation's growth, and especially in maintaining the living standards and prosperity of its citizens this kind of energy related GDP is indispensable.

Figure 2

Also, quality of life based on prosperity, education and life span is correlated to the per-capita energy consumption shown in figure 2. Quality of life is defined based on the UN's human development index, which is defined by individual prosperity (GNI per capita), education (mean and expected years of schooling) and life span (life expectancy at birth)⁽²⁾. Today, 80% of the world's population is below 0.8 on this scale, which rises to a maximum of 1.0.

Coal, Petroleum and natural gas fuels supply the majority of energy consumed, as illustrated in figure 3.

Figure 3

Nuclear and renewable energy combined represent little over 20% of all energy produced. In figure 4 the same trend of energy consumption is broken down by sector utilization. These three most utilized energy sources, which dominate every sector are also limited. Known, economically accessible supplies are being consumed rapidly. And the need for power will only grow with populations and as nations develop.

Figure 4

Energy Information Administration. Primary Energy Consumption by source and Sector, 2013. www.eia.gov/totalenergy/data/monthly/pdf/flow/css_2013_energy.pdf Accessed 2/23/2016

The world population growth is going to be major in Africa from now through 2050. Consider figure 5 below; more than half the population of Africa, and approximately 17% of the world population, are completely without access to electrical power. The quality of life impact on these 1.2 billion people is substantial⁽³⁾. Due to poor energy access, a larger 2.9 billion people rely on solid biomass fuels for cooking and home heating, known to cause serious health risks and 4.3 million premature deaths each year, according to WHO estimates.⁽⁴⁾

Figure 5

OECD and IEA 2015. World Energy Outlook 2015: Electricity Access Database. www.worldenergyoutlook.org/resources/energydevelopment/energyaccessdatabase/

Let us consider some simple numbers as of now:

Figure 6

Figure 6 is an estimate of how much of each fuel source would be needed to produce 100 quadrillion British thermal units. While the largest sources of energy need to burn billions of tonnes or of cubic feet to meet this kind of figure, a substantially smaller amount of Uranium-235 is needed. 100 Quads is very close to the amount of energy the U.S. consumes each year⁽⁵⁾.

For estimates on how much energy will be consumed as nations develop and needs are met, rounded population constants are chosen as follows. For more precise population estimates see The World Bank, U.S. Census, or Worldometers. In the U.S. a rounded population constant of 300 million people is used. While for China, India, and Brazil, as some of the nations where the most immediate growth in energy demand will be, a combined population constant of 3 billion people is used. Though China, India, and Brazil have a combined population of approximately 10 times the U.S., they're per capita energy use is approximately 1,200 Kilowatt hours per year--one tenth of U.S. consumption.⁽⁶⁾

Figure 7

Figure 7 uses BP analyses of known, economically recoverable fuel sources⁽⁷⁾. Regarding the nuclear fuels listed, conventional light water reactor nuclear power plants could only use Uranium-235 for fuel (and only a small portion of its energy). To use other fuels, such as the approximately 5 million tonnes of Thorium (which can be converted, breed, to Uranium-233) breeder reactor technology would have to be more fully developed and utilized. Figure 8 converts each fuel reserve into the potential energy it represents.

Figure 8

Consider U.S. consumption remains at 100 quadrillion Btu per year, and China, India and Brazil reach an energy consumption per capita equal to half of USA, the annual energy need for this part of the world is 600 quads. This is looking at 3.3 billion people, just to make the case, where the world population is closer to 7 billion people. At 600 quadrillion Btu the above carbon based fuels will last 85 years. At the same rate of consumption, the nuclear fuels will last 610 years. If the population doubles, the conventional fuels will last a much shorter time; unless the resources expand by order of magnitude.

Figure 9

The only source that can cater to the global prosperity for the next few centuries is nuclear fuel with breeding. Without breeding U-235 alone is not a viable solution for the long term, neither are the carbon fuels. There is a need for longer-term nuclear technologies with breeding. For this nuclear technologies must address four needs. One, the primary requirement is power production and breeding fuel (from U-238 to Plutonium, and Th to U-233). Two, there is a continued need for safer nuclear reactors. Three, to minimize long half life wastes, waste transmutation technologies are needed. And four, novel and innovative fuel technologies to support the above goals.

The needs of future reactors require technologies distinct from current nuclear power plants. The requirement of breeding nuclear fuel favors fast/epithermal reactors. Light water reactors cannot support reasonable breeding. Fast reactors lead to non-water cooled high temperature reactors. These differences require substantial development of materials, fuels and safety technologies. As a result, good test reactors might be needed.

Once an energy source for the global needs for the next few centuries is identified, the applications can be in any area of utilization by energy storage and conversion between various forms. Nuclear fuels not only reduce/eliminate green house gases, but also are the only source that can last the next few centuries.