Sustainability and policy - Climate Change: Biological and Human Aspects - page 467

lighting increased at a rate of around 2% a year (Parliamentary Office of Science and
Technology, 2005).
Finally, there has been one misunderstanding about energy efficiency that has re-
surfaced in the literature over the decades. This is that energy efficiency per se is
a substitute for energy generation. This is not strictly true. While it is eminently
important to improve energy consumption and production efficiencies, improved effi-
ciency by itself is meaningless: something needs its efficiency improving. Arguments
that the bulk of energy investment should be directed towards improving energy effi-
ciency are not practical. Investment will always be required first for energy production
(although hopefully this will be efficient production). Calling for investment to be
almost exclusively directed to energy conservation will fail because a nation needs
power production as well as consumption (Greenhalgh, 1990). Given this, and the
offsetting twin trends in improved energy efficiency and increased consumption, it
is unwise to consider improved energy efficiency by itself as a way of countering
increased greenhouse gas emissions. Instead, a package of measures is required, of
which increased efficiency of energy production and consumption is but one. The
others include low- (or zero-) fossil options such as nuclear and renewable energy,
and carbon-capture technologies as well as pricing. These are summarised briefly in
the following subsections.
The bottom line with regard to the savings that might be realised through energy
efficiency - should a broad quantified estimate be required - might amount to around
20% of consumption over 1990 efficiencies by 2025. (For a more detailed overview
see Cowie [1998a], which is in line with the IPCC [1990, 2001a] and the IPCC
emission scenarios [IPCC, 2000].) We will return to this broad estimate later in the
context of other potential savings that might accrue from possible energy strategies,
and, with regards to efficiency, low-energy strategies.

8.2.3 Prospectsforfossilcarbonsavingsfromrenewableenergy

Renewable (flow) energy resources are currently (using 2010 data) contributing to
6-7% of global commercially traded energy (BP Economics Unit, 2011). (This is up
≈

1% since 2002, reported in this topic's first edition.) It excludes wood and other
biofuels gathered locally and consumed. (Estimates for early-21st-century global non-
commercial local-biomass energy production are around 12 600 TWh year − 1 [Royal
Society of Chemistry, 2005], or about 1000 million t of oil equivalent, or mtoe,
which itself is close to about 10% of commercially traded energy.) Among renewable
commercially traded fuels, hydroelectric power (HEP) dominates (at about 6-8%
of global commercial energy traded in terms of coal-plant equivalents). However,
there are also wind, wave, geothermal and solar (thermal and photoelectric) forms
of renewable energy. These are not biological in nature and will not be described in
this topic save to say that, of these, wind is the renewable energy currently being
significantly developed but which in the middle of the 21st century's first decade
(2006) only contributed around 0.5% of global commercial energy.
Biofuels are biological, though, and a summary account appeared in the previous
chapter: they make a small but significant global contribution. Biofuels not only
have the potential to offset additions of fossil carbon to the atmosphere but, when