14 July 2012

Energy Efficiency and the Jevon's Paradox

Energy Efficiency  
a main plank in Greenpeace's 
Energy [R]evolution.

Energy efficiency is a key component of climate change policy, and is promoted as a low cost means to reduce greenhouse emissions and reduce peak demand. Energy efficiency is also a key component of the “soft energy path”, originally articulated by Amory Lovins in 1976 in his famous article in Foreign Affairs as a solution to energy supply concerns and declining resources, then later adopted as a solution to climate change.

Yet Jevon’s Paradox, or the energy efficiency rebound effect, suggests that some, or all, of the gains of energy efficiency are “taken back” in the long-run

Examples of Jevon's Paradox. 

The steadily declining cost of refrigeration has made almost all elements of food production more cost-effective and energy-efficient. But there are environmental downsides. Most of the electricity that powers the world’s refrigerators is generated by burning fossil fuel. Since the mid-nineteen-seventies, per-capita food waste in the United States has increased by half, so that we now throw away forty per cent of all the edible food we produce. According to a 2009 study, more than a quarter of U.S. freshwater use goes into producing food that is later discarded. 

Also discusses the improved efficiency of air-conditioners. In the United States, we now use roughly as much electricity to cool buildings as we did for all purposes in 1955. The problem with efficiency gains is that we inevitably reinvest them in additional consumption. Paving roads reduces rolling friction, thereby boosting miles per gallon, but it also makes distant destinations seem closer, thereby enabling people to live in sprawling, energy-gobbling subdivisions far from where they work and shop.
Read more:      http://www.newyorker.com/reporting/2010/12/20/101220fa_fact_owen#ixzz20ceOJXx3

The paper has two main findings.
The first is that Melbourne’s buildings and heating appliances are much more energy efficient than they were 50 years ago – they’ve shown sustained improvements over a long period, but what we tend to do is “spend” the efficiency dividend – we build bigger homes, we heat larger areas for longer, we have less people living in each home, and so on. The remarkable thing is that we use about the same energy per-person on space heating as we did in 1960, and the trend hasn’t changed much over the ensuing 50 years, even though modern homes are more than ten times as efficient. So the efficiency dividend has given us comfort that our grandparents could only dream about, so that’s a good thing, but if the objective is using efficiency to reduce greenhouse emissions, then it simply hasn’t worked. What has worked in Melbourne has been a shift to natural gas, which has relatively lower greenhouse intensity to other heating fuels.

The second main finding is that Melbourne’s heating is going to continue to rely on conventional large-scale energy, whether it is gas, or if we convert to electric heat pumps, then conventional dispatchable power. We hear a lot about renewables and smart-grids and electric vehicles plugging in and supporting the grid, and they capture the public’s imagination, but when you look at all of these things carefully, it becomes apparent that they’ll always struggle to move beyond a supplementary role. The reason for this is simple – during winter on cold or near freezing mornings, and in the early evening, people need affordable and reliable heating and this requires large-scale power on demand. Melbourne’s heating season lasts for 4 or 5 months, so you have this need, twice daily, for large scale dispatchable power.

1 comment:

  1. A strong indicator of the need to both improve energy efficiency and switch to using renewable energy.