Energy efficiency (EE) is a technological solution for eliminating
energy losses in the existing system. EE refers to using less energy
to produce the same amount of service or useful output [64]. This
can be carried out by the installation of EE technologies with the
objective of reducing load levels in the long-run, while maintain-
ing customer comfort or level of service [65]. Some of the
examples of EE are replacement of incandescent light bulbs with
compact fluorescent tubes [66], the use of automatic thermostats
and identifying and repairing leaks in compressed air. The impor-
tance of EE as a policy objective is linked to commercial, industrial
competitiveness and energy security benefits, as well as increas-
ingly to environmental benefits such as reducing carbon dioxide
emissions [64]. According to IEA, improved EE in buildings,
industrial processes and transportation could reduce the world's
energy needs in 2050 by one third, and help control global
emission of GHG [67]. EE and RE are twin pillars of a sustainable
energy policy [67], and maintain high priorities in the sustainable
energy hierarchy. EE has a national security benefit because it can
be used to reduce the level of energy inputs from foreign countries
and may slow down the rate at which domestic energy resources
are depleted.