Automobile manufacturers have been hard at work, figuring out
new technologies to improve fuel efficiency. So why aren't the cars
we drive today getting dramatically improved gas mileage? Fuel
economy actually increased by 60 percent between 1980 and 2006, but
at the same time the average curb weight of vehicles increased 26
percent, while their horsepower rose 107 percent. Consequently,
most of the gains in fuel economy have gone into compensating for
weight and horsepower. A recent study from Massachusetts
Institute of Technology economist Christopher Knittel found that
average fuel economy actually rose since 1980 from 23 miles per
gallon to only 27
miles per gallon.
And cars aren't the only place where greater efficiency has failed to translate to reduced consumption. Looking at even longer time scales, lighting efficiency has improved by more than many thousand-fold from sputtering candles to modern LEDs over the past three centuries. The result of this vast improvement in lighting technologies, writes Jeffery Tsao from the Sandia National Laboratory and his colleagues, “has been an increase in demand for energy used for lighting that nearly exactly offsets the efficiency gains.” They note, “When lighting become cheaper, economic agents become very creative in devising new ways to use it.” In fact, they predict that as lighting efficiency improves, say, with LED lighting, over the coming decades that the increased demand for lighting will again likely swamp any gains in energy efficiency.
Another study looked at trends in space heating efficiency [PDF] over the past 50 years in Melbourne, Australia. Modern houses are up to 10 times more energy efficient, yet the study found that modern Australians are collectively using just as much energy to heat their houses. Why? Modern houses are much bigger, people heat larger areas for longer, and fewer people live in each dwelling. The study notes, “The result that per-capita heating consumption has remained remarkably stable over the last 50 years.” However, modern Australians are much more comfortable in the winter than their grandparents were.
Read more: http://reason.com/archives/2012/07/17/the-paradox-of-energy-efficiency
And cars aren't the only place where greater efficiency has failed to translate to reduced consumption. Looking at even longer time scales, lighting efficiency has improved by more than many thousand-fold from sputtering candles to modern LEDs over the past three centuries. The result of this vast improvement in lighting technologies, writes Jeffery Tsao from the Sandia National Laboratory and his colleagues, “has been an increase in demand for energy used for lighting that nearly exactly offsets the efficiency gains.” They note, “When lighting become cheaper, economic agents become very creative in devising new ways to use it.” In fact, they predict that as lighting efficiency improves, say, with LED lighting, over the coming decades that the increased demand for lighting will again likely swamp any gains in energy efficiency.
Another study looked at trends in space heating efficiency [PDF] over the past 50 years in Melbourne, Australia. Modern houses are up to 10 times more energy efficient, yet the study found that modern Australians are collectively using just as much energy to heat their houses. Why? Modern houses are much bigger, people heat larger areas for longer, and fewer people live in each dwelling. The study notes, “The result that per-capita heating consumption has remained remarkably stable over the last 50 years.” However, modern Australians are much more comfortable in the winter than their grandparents were.
Read more: http://reason.com/archives/2012/07/17/the-paradox-of-energy-efficiency
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