Don’t switch on all your lights. (istock)
Don’t switch on all your lights. (istock)

How to become energy savvy

  •  In energy terms, just one international flight exceeds our annual electricity use
  • A useful way to visualize your energy use is to think in terms of light bulbs

Climate change is a complicated subject—it can be difficult figuring where you, in your individual capacity, fit in and what you can do.

The fact is that the insect population is declining,coral reefs are dying,glaciers are melting,sea levels are rising and the weather is becoming unpredictable and extreme.

Read any simple summary of the latest UN climate panel report, often called a “bombshell", and it tells you that the situation is grave.We have just 12 years to cap temperature rise,or face severe droughts, storms, floods and loss of life.

At the heart of the climate crisis is our energy usage which,with the exception of renewable energy,ultimately translates to green house gases. So I thought of beginning by trying to understand my personal energy use. I am quantifying it because numbers give a perspective,a better understanding of the problem, which in turn can help us make informed decisions.

My first step was to calculate the amount of electricity (supplied mostly by coal and gas power stations) we use in our house. My domestic energy consumption for the year is 13,122 units. It’s on the electricity bill; just add it up for the year.

Now here comes the shocker:My wife and I took a round-trip to New York last year. A quick Google search tells me that this was a flying distance of around 11,734km,one-way, or 23,468km for the round-trip. The aircraft we flew in was a Boeing 777-200. Its fuel consumption per seat is 0.0325 litres per km (again, google “aircraft fuel economy" and you will get the information).

Multiply these numbers, and you get the per person fuel consumption on my round-trip flight: It works out to 763 litres (that is, the distance 23,468km multiplied by 0.0325, the per seat/per km fuel use).

Now, fuel uses about 10 units of energy for every litre (look up energy density of petroleum). So, my personal use of 763 litres translates to 7,630 units of energy. For my wife and I together, this comes to a whopping 15,260 units. In energy terms, just one international flight exceeds our entire annual electricity use.

Flying is very, very energy intensive. To get a feel of how much fuel is involved, imagine that instead of flying from Delhi to Mumbai,all the passengers decided to drive there, two to a car. The amount of fuel that all these cars use, put together, would be equivalent to the fuel needed for one flight.

A useful way to visualize your energy use is to think in terms of light bulbs. David MacKay was a British physicist who was also the chief scientific adviser to the UK government on climate change. In a brilliant YouTube video, he explains how you can measure your energy use in terms of an ordinary 40-watt light bulb.

If I add up the energyused at myhome (electricity and cooking gas), add up my car petrol consumption and the flight to New York, it translates into keeping switched on roughly 110 light bulbs of 40 watts each, day and night, for the whole year. This is very high energ yuse:It’sabout that of an average home in the UK, and much higher than the average for an Indian home.

I tried to break it down further. If I look at how these 110 light bulbs are divided in my life, it comes out to approximately 40 bulbs for electricity, 40 bulbs for flying, 20 bulbs for driving, and 10 bulbs for cooking.

So, the moral of the computation is, reduce the number of flights you take in a year, and if you cannot do that, at least try and cut down on your domestic energy use.

There’s another thing you can do to reduce energy use: If you have a terrace, paint it white with solar reflective white coating. According to the White Roof Project, a non-profit dedicated to climate change,a whiteroof“reflectsup to 90% of sunlight(traditional black roofs reflect only 20%)." It keeps buildings cool and reduces energy use.

There are several other steps an individual can take. The fact is, we need to acknowledge that we are in serious trouble, and we don’t have much time.

*Shekhar Bhatia is a science buff and a geek at heart.