Energy efficiency and the rebound effect

LEED Platinum-rated OHSU Center for Health & Healing (photo by Brian Libby)

In the latest issue of The New Yorker, writer David Owen looks at a troubling potential conundrum of energy efficiency: the "rebound effect". The more efficient our cars, refrigerators and air conditioners become, the more of them get produced, and so the actual reduction in energy disappears.

There are all kinds of examples throughout history.

The Ford Model T, manufactured between 1908 and 1927, averaged between 13 and 21 miles per gallon. A century later, we've learned to use gasoline much more efficiently, but that has only led to bigger cars stuffed with energy-sucking electronic gadgets.

A refrigerator sold in America today uses three quarters less energy than the 1975 average, even though it is one-fifth larger and costs 60 percent less. Yet during this same 35-year time period, the global market for refrigeration has grown exponentially; moreover, far more people in the US now have a second fridge or freezer.

On a macro scale, this proves out too: Between 1984 and 2005, electricity production grew by about 66 percent despite economy-wide energy efficiency gains. Some of this can be attributed to population growth, but not all. Per-capita energy consumption rates also increased during this period, even though energy use per dollar of Gross Domestic Product fell by around 50 percent.

Owen's article is largely based around an idea called the "Jevons paradox" that dates to an 1865 book by Englishman William Jevons called "The Coal Question". At the time, Great Britain was the world's leading industrial, military and economic power. But Jevons argued that it couldn't last. The country's coal supply was rapidly depleting, and he postulated that even increased efficiency in the use of coal would not delay the process. "It is wholly a confusion of ideas," Jevons wrote, "to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth." The more efficiently we use power, the more power we'll want to use. This is also commonly known today as the rebound effect.

LEED Platinum-rated AIA Center for Architecture (photo by Brian Libby)

All this begs the question: what about buildings?

After all, few entities have been the focus of energy efficiency goals more than buildings. Together, homes and buildings consume more than a third of total energy used in the United States today. Locally and regionally, organizations like the Northwest Energy Efficiency Alliance (whose BetterBricks wing is a Portland Architecture sponsor) have devoted millions of dollars to designing new buildings and renovating old ones so that less energy is consumed. And the design community has become a national leader in sustainability. Portland has more LEED-rated buildings than virtually any other American city, especially when you measure it on a per-capita basis. The first LEED Platinum-rated condo, large medical facility, and National Register-listed building are all located here.

Energy efficiency is also part of a national strategy, called "the fifth fuel" after coal, petroleum, nuclear, and renewables. In 2007 the United Nations Foundation called energy efficiency gains "the largest, most evenly geographically distributed and least expensive energy resource."

Is it a waste of time, energy, money and resources to design and build buildings with better insulation, more natural light, and smaller mechanical systems? I'm not completely sold on the Jevons paradox as it relates to architecture today, nor are experts unanimous about its relation to other current energy issues. 

For starters, as explained to Owen by Lee Schipper, a senior research engineer at Stanford University's Precourt Energy Efficiency Center, the rebound effect is minimal because energy is a relatively small part of the overall economy, between six and eight percent. Efficiency gains today have much less power to stimulate consumption than industrial manufacturing gains in the 19th century like Jevons wrote about.

More specifically as it relates to architecture, building green needn't be seen as a stimulant to building more. There is, perhaps, an argument that in our drive to weatherize homes we will spend as much energy on manufacturing and transporting new materials as will be gained from reduced heating and cooling. But what are we going to do, stop fixing up our buildings or building new ones?

The one area in architecture where the Jevons paradox could hold true is with air conditioning. Just as there are more refrigerators and freezers in use both overall and per capita today, wiping away much of the efficiency gains made from appliances using less energy, air conditioning is much more prevalent than in previous generations. It's part of the reason that regions and cities with very warm climates like Arizona and Nevada and the South saw large population influxes over recent years. Then there's the international spread of air conditioning to developing countries. According to Owen's article, between 1997 and 2007 the use of air conditioning in China tripled. In india it's expected to increase almost tenfold between 2005 and 2020. Owen cites a 2009 study saying air conditioning already accounts for 40 percent of the electricity consumed in metropolitan Mumbai.

Even so, the rebound effect with air conditioning - overall use eating up efficiency gains - is not an argument for the ineffectiveness of green building and architecturally oriented energy efficiency. On the contrary: if millions more people are using AC, it's even more important that this happen in buildings with tightly sealed thermal envelopes (without leaks, in other words) so the AC be utilized as efficiently as possible. Therein, perhaps, lies the broader answer with questions of the rebound effect. Maybe it does exist, to a degree, but if so, that's an argument to fight for efficiency gains all the more.

If there's a lesson to be learned from hashing over the Jevon paradox and the rebound effect as it relates to energy efficiency, perhaps it's a matter of re-learning a bit of common sense: all the efficiency gains in the world don't matter if we don't also curb demand. And yet reducing demand is the last thing any economist wants to hear. The 2000s decade was largely about creating exponentially larger demand for real estate by relaxing home ownership financing rules. And even if we hadn't got carried away building new suburban cul de sacs and urban condos over the last ten years, the population here and especially in other countries continues to increase. All those bodies need electricity of some sort.

Yet there are things we can do on the demand side. Jimmy Carter was the last American president, more than three decades ago, to tell us to be smart about little things like turning the lights off in rooms we don't occupy. Behavior can be adjusted on the macro level, and that's as important as technical advances in efficiency. It's just that having more efficient air conditioners, TVs and refrigerators has to be coupled with anti-sprawl planning, mass transit, and other factors. And then there's the question of energy taxing. Price is as much a determinant of energy or other product/service use as efficiency. As even Jevon would have acknowledged 135 years ago about coal, how efficiently we use anything is merely an extension of how much we want or need to use it.

Comments

[Kettlemoraine]

Thank you so much for writing this brilliant article, Brian! It's about time that someone brought up the rebound effect.

We have a more urgent need than ever to curb demand, buy locally and live within our means. Great work, as always, including your amazing photos that we always enjoy!

[Ian Manire]

I wonder how longevity, aka loveability or cultural sustainability, plays into the returns on energy investment equation. One way of effectively reducing demand is to reduce demand for the merely new, in favor of the good. That doesn't work with power, obviously; but for the material investment and the energy required toward material uses, surely there's a point past which it's "all profit," as it were.

And that's surely where preservation and traditional new design comes into play--people might not tear down and rebuild for novelty's sake (or more ironically, to build a new "green" building in its place) that which they actually value culturally--which lets the material value of a building really pay off.

Those buildings are also in a better position to continue functioning in a reduced- or post-HVAC-obsessed world. With real wall mass, reasonable openings-to-wall ratios, high ceilings, operable windows and transoms, etc., they will be more comfortable than the hermetically sealed, totally AC-dependent post-War buildings, when the real costs of energy resources start to really be considered.

Excellent post, with a lot to consider.

[valkraider]

This certainly has been shown to be true with fuel efficiency in vehicles. People get a more fuel efficient vehicle and they tend to drive more...

I am not sure this is really true with energy efficiency in general.

Are we building more buildings *because* they are energy efficient? Are people buying more refrigerators *because* they are energy efficient? Did people get big screen TVs *because* they are energy efficient?

Or is there something else driving the increased adoption, and better efficiency is either a selling point or a government mandate?

I have always had two refrigerators. The increased efficiency has not made me go buy additional ones, but it has made the two that we have consume much less energy.

I don't know anyone who has gone out and bought an air conditioner because they consume less energy now than 50 years ago.. I know people who put in air conditioning because they didn't like being hot.

I bought a new TV because our old one broke. Not because the new LED one I bought uses less energy than the old one. People I know with more than 5 TVs (and I know a few) don't have so many because - "hey now they are efficient!" - they have more TVs because they wanted TVs all over their house. In fact, I would wager that some of their TVs are *less* efficient than older models (the first few generation Plasma TVs sucked electricity like no TV before!).

No one builds an *Extra* building because it can bee LEED compliant. We build buildings because we need/want the buildings.

The new XBox 360 is more efficient than the original, and the new iMac is more efficient than older models. But people are not buying them because they are more efficient, people buy them because they want to play the latest games or have a nice new computer.

Since people are buying, building, and using - why not make them as efficient as possible? If I am gonna have a TV anyway, I might as well have one that consumes less energy. If we are gonna have buildings, might as well make them LEED...

And actually, in California at least - because of the higher efficiency of products - California per-capita energy consumption has been trending slowly downward even as the totoal energy consumption has been trending upward.

Did you buy a computer because they can be energy efficient, or did you buy a computer because you could read and respond to blogs with it?

Now transportation fuel is an entirely different beast... We definitely ship more stuff and drive more and whatnot as efficiency increases...

[Portlandpreservation.wordpress.com]

Interesting post Brian and great insight Ian. There's definitely something to be said about how older buildings reduce consumption simply because they still exist. Studies have shown that pre-1920 construction is often as energy efficient as what gets built today. It gets even better when those older buildings are rehabilitated - as in the recent upgrades to the Morgan Building in Downtown. Imagine that, a system that tells you when to open or close the windows rather than complete reliance upon HVAC systems.

On the refrigeration note, The size of our fridges here in the states are crazy compared to most of those in Europe. Part of that has to do with what we insist on refrigerating needlessly. As someone who lives in an older house, I had a heck of a time finding a modern fridge that would actually fit in our kitchen. Most of those on the US market are made more efficient because they include massive amounts of insulation - making their physical size ridiculous.