Unfortunately, it did not reduce carbon emissions much.
Media reports say that electricity consumption went down by several megawatts during that hour.
But what we forget is that greenhouse gas carbon emissions do not come from lighting. They come from electric power plants that use coal or fossil fuels. And if the power plants do not shut down for Earth Hour then, despite the one-hour drop in consumption, greenhouse gases will continue to be emitted. Unless, of course, the power sources are from renewable energy sources like the sun, wind or relatively cleaner fossil fuels, such as natural gas turbines, which emit slightly less greenhouse gases.
Every engineer worth his salt knows that simply switching off the lights for one hour does not cut much carbon emissions because the power plants will simply operate on 'spinning reserve' mode.
One hour is not enough time to shut down and restart a coal plant. The turbines are so large that they will keep spinning even if the coal-fired boiler is stopped.
The boiler itself will be subjected to thermal stresses if turned off and restarted within the hour. So, during Earth Hour, coal power plants are emitting greenhouse gases in anticipation of the starting surge current from everyone turning their lights on at the same time.
Rather than taking part in Earth Hour activities which hardly reduce carbon emissions, try doing these things instead:
The simple act of defrosting your refrigerator, for example, while hardly the stuff of social media discussions, will make your appliance more efficient for a few days to a few weeks - enough time for greenhouse-gas-spewing coal plants to react, especially if millions of refrigerator owners do the same thing.
By removing the accumulated frost, you can improve the efficiency of an old refrigerator without switching to a more energy-efficient one.
It will add up to a significant number of watts if millions of people try to reduce their energy consumption.
From a government and national perspective, of course, it is important to continue trying to switch to renewable energy as long-term demand goes up.
But unless you are a policy-maker, a utility owner or a home owner interested in installing solar and wind panels, the best way you can save energy is to maximise the energy efficiency of your home and surroundings.
As for the argument that Earth Hour is meant to be just a symbolic act, well, the time for symbolism is over. This year is the 20th anniversary of the Rio Declaration on sustainable development. Surely now is the time to act.
I'm all for the spirit of Earth Hour. But let's go about it in a way that actually reduces carbon emissions.
The writer is an energy consultant who writes on clean energy issues. His latest project is the Greenthinkingfable (http://greenthinkingfable.blogspot.com)
