Burn .. Fill .. Go !!!

We all believe that electric vehicles are non- polluting and environmentally friendly. Yes, they compromise on top speed, have a slower acceleration and take a long time to get charged up, unlike gasoline or diesel engine run automobiles which take less than a couple of minutes for refuelling, but considering the traffic which is building up every day in our cities how often do you get an opportunity to drive fast accelerate?

The rate of re-charging your batteries is still a problem. Better battery re-chargers are being built but none is comparable with the time taken to fill your tanks with that of petroleum fuels. One more major claim by the electric vehicle manufacturers is “Environmental Friendliness”. They claim their vehicles don’t pollute. Does not emit any harmful gases. No engine – No fuel – No harmful gases. 

That's what they say. But is it so?

Let’s dig in deep.

India generates 59% of all its electricity through coal. 17% through Hydro Electricity. 10% through fossil fuels (Gas and Diesel). 2% through Nuclear and the remaining through renewables.

Most of the fossil fuel power is dedicated to the industries. The renewables are seasonal, we get winds only in the months of Feb – March and June to August. The rest of the times the wind mills spin, but do not generate. There is something called a minimum wind velocity, only beyond which a wind mill can generate electricity, although solar is on throughout the year. Hydro power is again seasonal and rarely runs on full capacity even during the monsoon seasons or post winter.

The cities mostly get power from the coal fired power plants and Nuclear. As we see, nuclear contributes very little (only 2%), so for the sake of an argument, we shall consider that the city gets its electricity from coal fired power plants.

Now, how much coal do we need to burn? Before answering that, I’d like you to know something.

The electricity meter in front of your house in which you see a disc spinning inside, that disc when it spins one full circle, it means that you have consumed 1 kilo Watt Hour of electrical energy. It is equivalent to any electrical device/devices consuming 1000 Watts or 1 kilo Watt of power for one hour. Your average fan is about 150 Watts and a tube light 40 Watts, your refrigerator 500 Watts.

So if you turn on your Refrigerator, a couple of fans and 5 tube lights for one hour, you would successfully consume 1 kilo watt hour of electrical energy. That my friend is called a “Unit of Electricity”. So check your Electricity bill and find out how many units of electricity you have consumed and count the number of fans and lights to verify the same.

That apart. The coal fired power plants are not in your neighbourhood, they are generally located far away from cities. That is done to save you from the pollution it throws into the atmosphere.

What actually happens in a Coal fired power plant? Coal is burnt. This burning of coal produced heat. This heat is used to convert water into steam. This steam is then sent to a turbine. The steam flows through the turbine and spins the turbine. The turbine is connected to a huge generator and the generator spins along. This process produces electricity which is then transferred through the transmission cables which run a few thousand kilometres to reach the city distribution station. The city distribution then sends an underground cable to your door step from which you get electricity.

Now now now …. There is a lot happening here. Lot in terms of energy.

First, generating the electricity; it is known that the efficiency of electricity generation in a coal fired power plant is close to 40%. It means you have to burn two and a half times the energy equivalent of coal to generate one kWh of electricity. That is roughly about 500 grams of coal for a unit of electricity.

The carbon content of coal is about 70%, or 700 grams of carbon per Kg of coal. Upon complete combustion where this carbon gets converted to CO₂ two Oxygen atoms are required by every atom of Carbon, which is about 1860 grams of oxygen. The sum is then 700 + 1860 = 2560 grams of CO₂/KG of coal. So to produce a unit of electricity, you burn half a kilo of coal which emits 1.28 kilos of Carbon dioxide into the atmosphere.

Now, the electricity to travel from the generating station to your doorstep has to pass through a lot of devices. Most of them are transformers. Whenever the electric current passes through them, there is a loss, either as heat or as sound. That ‘trrrrrrrrrrrr…’ noise that you hear when you go near a transformer, that a loss. The efficiency of a transformer is about between 95– 98%. There are at least seven transformers that are employed between the Generator at the power station and your door step. At these efficiencies through the seven transformers, about 80% of the electricity that is generated reaches your home. Electric vehicles deploy a motor to spin the wheels. This motor operates at around 65% average efficiency. Multiply both efficiciencies and we get 52% as our overall electrical efficiency. So, we basically need to generate 2 units of electricity for every one unit to be consumed. Therefore you emit 2.56 kilos of CO₂ for every unit of electricity you consume at home.

Coming back to electric vehicles. The general mileage which all the electric bike manufacturers promise is something close to 40 kilo metre for one full re-charge of the battery. A full recharge consumes close to one unit of electricity. So 40 km/kWh is what it gives you. That is 2.56 KG of CO₂ emitted for 40 kilometres.

A bike running on petrol also gives you a mileage of 40 km per litre. One litre of petrol weighs 750 grams. The carbon content of petrol is about 87%, or 652 grams of carbon per litre of petrol. In order to combust this carbon to CO₂, 1740 grams of oxygen is needed. The sum is then 652 + 1740 = 2392 grams of CO₂/litre of petrol. That is something close to 2.4 kilos of carbon dioxide emitted.

Assumptions and numbers here and there might vary a little. But long story short, both emit the same amount of Carbon Dioxide into the atmosphere. Although an electric vehicle will not irritate the cyclist on the road, just behind you pedalling his lungs out, by giving him a fresh dose of poisonous gases to inhale.

So you do release a lot of harmful gases but the locations are different. Unless, you charge your electric vehicles using a renewable source of energy like a solar panel dedicated to charge your electric vehicle.

So, the environmentally conscious citizen can choose between the two depending on his needs. On the contrary, the budget conscious citizen can pick an electric vehicle as he gets to drive 40 Kilometres for just Rs. 5/-, that is 13 Paisa per kilometre, whereas petrol prices are soaring through the roof. Choose wisely!!!