Friday, 8 October 2010

Why Energy Efficiency Does not Decrease Energy Consumption

Why Energy Efficiency Does not Decrease Energy Consumption

By Harry Saunders

I recently co-authored an article for the Journal of Physics ("Solid-state
lighting: an
energy-economics perspective" by Jeff Tsao, Harry Saunders, Randy Creighton,
Mike Coltrin, Jerry Simmon, August 19, 2010) analyzing the increase in
energy consumption that will likely result from new (and more efficient)
solid-state lighting (SSL) technologies. The article triggered a round of
commentaries and responses that have confused the debate over energy
efficiency. What follows is my attempt to clarify the issue, and does not
necessarily represent the views of my co-authors.

More Efficient Lighting Will Increase, Not Decrease, Energy Consumption

Our Journal of Physics article drew on 300 years of evidence to shows that,
as lighting becomes more energy efficient, and thus cheaper, we use
ever-more of it. The result, we note, is that "over the last three
centuries, and even now, the world spends about 0.72% of its GDP on light.
This was the case in the UK in 1700 (UK 1700), is the case in the
undeveloped world not on grid electricity in modern times, and is the case
for the developed world in modern times using the most advanced lighting

The implications of this research are important for those who care about
global warming. In recent years, more efficient light bulbs have been widely
viewed as an important step to reducing energy consumption and thus
greenhouse gas (GHG) emissions. Moreover, the Intergovernmental Panel on
Climate Change (IPCC) of the United Nations and the International Energy
Agency (IEA) have produced analyses that assume energy efficiency
technologies will provide a substantial part of the remedy for climate
change by reducing global energy consumption approximately 30 percent -- a
reduction nearly sufficient to offset projected economic growth-driven
energy consumption increases. Many have come to believe that new, highly-efficient, solid-state lighting
-- generally LED technology, like that used on the displays of stereo
consoles, microwaves, and digital clocks -- will result in reduced energy
consumption. We find the opposite is true, concluding "that there is a
massive potential for growth in the consumption of light if new lighting
technologies are developed with higher luminous efficacies and lower cost of
light." The good news is that increased light consumption has historically been tied
to higher productivity and quality of life. The bad news is that energy
efficient lighting should not be relied upon as means of reducing aggregate
energy consumption, and therefore emissions. We thus write: "These
conclusions suggest a subtle but important shift in how one views the
baseline consequence of the increased energy efficiency associated with SSL.
The consequence is not a simple 'engineering' decrease in energy consumption
with consumption of light fixed, but rather an increase in human
productivity and quality of life due to an increase in consumption of
light." This phenomenon has come to be known as the energy "rebound" effect.

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