Earth Hour – The Asymmetry Principle vs The Rebound Effect

March 24, 2010 by  
Filed under Insights

Earth Hour Singapore is back again and takes place this Saturday, 27 March 2010. Individuals, organisations and businesses are encouraged to switch off their lights for one hour from 8.30pm to 9.30pm, or longer. Earth Hour is organised by WWF and is “a call to stand up, to take responsibility, to get involved and lead the way towards a sustainable future.”

The switching off of lights is a symbolic act for everyone to take responsibility and fight climate change. Find out more about what you can do and pledge your support for Earth Hour.

Earth Hour has been successful in gaining support and participation over the past few years. For this year’s Earth Hour, we would like to remind everyone that Earth Hour is not just about switching off lights, it’s about two key forces at work – The Asymmetry Principle vs The Rebound Effect:

The Asymmetry Principle

In his book, The End of Energy Obesity: Breaking Today’s Energy Addiction for a Prosperous and Secure Tomorrow, energy economist Peter Tertzakian describes The Asymmetry Principle as:

the lopsided relationship between how much raw energy is available at the primary source — for example, at a natural gas well — and the small fraction of energy that is actually put to useful work at the consuming end — for example, in lighting a light bulb. The principle states that a unit of energy saved at the consumer level amplifies into multiple units of energy saved at the source. In effect, the asymmetry principle exposes the high levels of inefficiency in society’s energy systems and highlights the tremendous leverage offered by efficiency gains and conservation in mitigating source energy consumption.

He gave the example of a light bulb:

  1. 100 energy units of natural gas at source
  2. 40 energy units remaining due to conversion to electricity
  3. 35 energy units remaining due to transmission losses
  4. 2 energy units remaining due to conversion to light

In this example of a light bulb, reducing the consumption of one unit of energy (as light) actually saves the production of 50 units of energy (as natural gas) if you account for the inefficiencies and energy losses in fuel production, electricity generation, electricity transmission and thermal conversion to light.

To put it simply, when you switch off the lights and save X units of energy, you are actually saving more than X units of energy as the energy savings amplify back to the energy source.

Therefore, energy conservation or reducing your energy consumption plays an important role in reducing carbon emissions. When you switch off your lights or appliances at home during Earth Hour, it is not merely the act of pressing a switch but the multiplying and amplifying effects of conserving the energy resources upstream.

However, energy conservation must be done by everyone daily to make a significant difference such that The Asymmetry Principle plays out. Take the example of last year’s Earth Hour:

In Singapore, turning off lights and electrical appliances during Earth Hour saw a 42-megawatt drop in electricity demand. This is equivalent to 40 per cent of the electricity demand in Ang Mo Kio for that hour, said Energy Market Authority (EMA).

However, there was no real decrease in carbon emissions.

Since we only used 1 per cent less electricity as we normally would have in that hour, the generation companies (gencos) burnt just as much fuel as usual, said EMA.

The New Paper

For actual reduction in the fuel usage and carbon emissions, everyone in Singapore (households and organisations) must play a part in energy conservation on a daily basis to reduce Singapore’s energy demand. Ad hoc or yearly Earth Hour actions will not be sufficient to effect an actual change in the reduction of energy resources and carbon emissions.

The Rebound Effect

The Rebound Effect usually refers to the behavioral responses to the introduction of new energy efficiency technologies or measures, which tend to offset the actual benefits of the new technology or measures. In other words, actual energy savings is less than expected savings.

For example, if you replace a 20W incandescent light bulb with a 10W energy efficient compact fluorescent bulb, the energy saving should be 50%. However, the actual energy saving is usually less than 50% because as you find that you pay less for lighting, you tend to be less concerned with switching it off. The increased usage thus eat away some of the energy savings from the more efficient light bulb.

Here, we will adapt The Rebound Effect to explain that the actual energy or carbon emission savings could be less than the expected savings from energy conservation. When you reduce energy or carbon emissions from one activity but use more energy or generate more emissions by switching to other substitute activities, then the actual savings is less than expected savings.

For example, you usually read a book on a Saturday night. But to support Earth Hour, you switch off your lights, thus saving X units of energy. In the dark, you can’t read so you switch on the TV and watch it for the whole night. The actual energy savings is thus less than the expected X units of energy savings.

Or instead of staying at home, you decide to drive your car to an event that celebrates Earth Hour. The additional carbon emissions could be more than the expected emission savings from switching off the lights.

You should still support Earth Hour but remember The Rebound Effect and remind yourself that the Earth Hour activities you take part in should not be causing more energy consumption or carbon emissions as compared to your usual activities.

The Asymmetry Principle vs The Rebound Effect

Earth Hour is really about The Asymmetry Principle vs The Rebound Effect. We need to see more of The Asymmetry Principle and less of The Rebound Effect.

We need more people to switch off their lights and reduce their energy consumption daily so as to amplify the energy savings at the source. We need less people to switch to other substitute activities that consume more energy or generate more emissions.

So remember for this year’s Earth Hour, everyone must take action to conserve energy daily and ensure that our actions do not contribute to the problem we are trying to solve.

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