ABSTRACT
Global energy consumption during 2010 was recorded as 524 quadrillion British thermal units (Btu). Various energy planning agencies have projected that this consumption will increase to 630 quadrillion Btu in 2020 and might rise to 820 quadrillion Btu in 2040 (U.S. Energy Information Administration [USEIA] 2013). This growth in energy consumption is driven by increasing growth in industrial activity in developing countries and changing lifestyles. Currently, most energy is obtained by the burning of fossil fuels, mainly coal, oil, and natural gas. Other major sources of energy are the nuclear reactors and hydroelectric power projects. The burning of fossil fuels results in the emission of greenhouse gases, especially CO2 in the atmosphere, which has been identied as a major cause of global warming. Many scientic studies indicate that a temperature increase of 1.8°C-4.0°C may occur in the global temperature during the twenty-rst century, which may cause serious and irreversible effects, such as the melting of polar ice, gigantic oods, and a rise in sea level (Intergovernmental Panel on Climate Change [IPCC] 2007). The disposal of nuclear fuels and nuclear security issues hinder the widespread use of nuclear energy. Large hydroelectric dams suffer from the issues of seasonal ow uctuations and periods of draught. Furthermore, obtaining consent for more large hydroelectric sites is becoming increasingly difcult as such projects are opposed by local communities and environmentalists due to associated ecological disruptions (Sims 2008). Therefore, present energy supply trends are considered as being unsustainable for the long term.
