Environmental Engineering Reference
In-Depth Information
10
Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can
be achieved through simply reducing the amount of energy used to perform some task, possibly
also reducing the amount of the task completed, or by increasing the efficiency of energy use, if
this produces decreased energy consumption without reducing the amount of the task completed.
Energy efficiency is using less energy to provide the same service (Lawrence Berkeley National
Laboratory 2011), while energy conservation is any reduction in use of energy. Energy can be con-
served or reduced without improving energy efficiency, but energy efficiency cannot be improved
without reducing the amount of energy required to perform a task. Thus, energy conservation and
energy efficiency are related, but are not the same. This often leads to some confusion. Energy
conservation is broader than energy efficiency because it includes efforts to decrease energy
consumption through behavioral change, in addition to using energy more efficiently. Examples
of conservation without efficiency improvements are heating a room less in winter, using the car
less, or enabling energy saving modes on a computer. Examples of improving energy efficiency
include replacing an appliance, such as a refrigerator or clothes washer, with a model that provides
the same service, but uses less energy.
Improvements in energy efficiency are most often achieved by adopting a more efficient tech-
nology or production process (Diesendorf 2007, 86). Because the existing stock of energy-using
appliances and other equipment is so huge in the American economy, energy conservation and
efficiency can be thought of as energy resources that can be used to meet human needs. The no-
tion of a “soft energy path,” with a strong focus on improving energy efficiency, was popularized
with the term “negawatts,” or meeting energy needs by increasing efficiency instead of increasing
energy production (Lovins 1977). Perhaps the term was too cute to catch on, but the general idea
has been increasingly accepted over the objections of some electric utility managers, who insisted
that energy efficiency measures were “one-time” measures that, after implementation, would not
be available in future.
This “one-time” view ignored the enormous number of washing machines already in use, the
fact that the number seems always to be increasing, that existing washing machines age and must
be replaced, that they cannot possibly be replaced all at once, and that technological advances have
continued to make them more energy-efficient over time. Moreover, this is true with all types of
appliances currently in use, as it is with housing stock, factory buildings and processes, commercial
establishments, automobiles, and other energy-using devices. Everything eventually wears out
and can be replaced with something more energy-efficient. Consequently, the opportunities for
improving energy efficiency and increasing energy conservation are so numerous in the American
economy that they are actually increasing with the pace of technological innovation rather than
being “one-time” measures that decrease in the aggregate over time. Thus, energy conservation
and efficiency may be conceived of as energy resources comparable to oil, natural gas, or coal.
National energy use can be conceived as comprising four broad sectors: transportation, resi-
dential, commercial, and industrial, as illustrated in
Figure 10.1.
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