Now that summer’s here we’re all getting ready to face more and more power cuts. Candles are kept handy and people are wary of using lifts. This year the government has warned that there will be even more power shortages throughout the country and has asked everyone to cut down on their use of electricity.
Of course we should save electricity because there isn’t enough to go around. But there are also other sound reasons why you should cut down on how much electricity you use.
We think of electricity as being a particularly clean form of energy because when we use it for trains, TV sets, computers or electric lights, it doesn’t give off any smoke or have dangerous waste products. But the process of making electricity is certainly polluting, whether it is done by coal-fired thermal power plants or diesel generators. Electricity-generating power plants release a lot of carbon dioxide, and we know that carbon dioxide emissions are causing climate change. Nuclear reactors may not be polluting in this way but their environmental problems may be worse, as we saw in the Chernobyl disaster. Hydropower, which was once thought of as being harmless, is now seen as having its own problems. These include the fact that the dams needed to produce hydropower block rivers and get people kicked out of their own land.
So using less electricity can only be a good thing. Let’s see how you can do this.
What uses the most electricity in a home?
To find out, we first need to understand a tiny bit about electricity. When electric energy in the form of a current flows in a wire and meets with resistance, it does ‘work’. Electric power is the amount of work done by an electric current in a time period. This is measured in units called ‘watts’. Our appliances convert this work into heat, light or mechanical energy. Converting electricity from one form into another is what uses it up and we pay for what we convert. We know how much we are using because most electrical gadgets have the number of watts they use written on them. As an obvious example, a 100-watt light bulb uses 100 watts! An air conditioner uses about 3500. The more the watts, the more electricity a machine uses.
One simple rule is that converting electricity into heat or mechanical motion uses up more of it then turning it into sound or light energy. The household appliances that use up the most electricity are air conditioners which convert electricity to mechanical energy. This mechanical energy is used to pump, compress and expand a coolant gas, which is then used to cool down a room. The next biggest electricity user is heaters, both room heaters and water heaters which convert electricity energy to heat energy. This is done using a metal’s natural resistance to electricity to make it hot and pass this heat to the room or to water. Then come washing machines which mechanically agitate water and clothes to clean them. Many washing machines also have built-in heaters to warm the water.
The way to save electricity in these machines is obviously to turn the machines off! But since this is not always possible we can try and reduce the energy conversion process. We can understand this by looking at refrigerators which also work like air conditioners and are left on all the time. Yet they don’t use that much electricity because of the closed area inside the refrigerator and the insulation and sealing. Once the storage space inside the refrigerator is cool a thermostat shuts the motor down until the temperature rises, when it switches on again. Refrigerator and insulation technology has improved so much that modern ones actually use little energy compared to those of just a few years ago. But even in these, if you left your refrigerator door open, it would use a lot more electricity than an AC. In fact if a fridge door is opened and closed more often than usual, as when you have guests, you will see the electricity bill will go up. So to use less electricity, an air conditioned room can be sealed and properly insulated from outside heat and then the AC would need to do far less work to bring the temperature down.
This is also true of a water heater. Every time it is switched on it heats up the water and some of the surrounding metal container. If you could for example have everyone who was using hot water use it one after another and then switch it off, you would only be heating water instead of the metal casing. In any case, tank type storage water heaters waste electricity because they keep the water hot all the time, even when no one needs it.
Fans work differently, they don’t actually bring the temperature down, they just mechanically blow the air around, providing a cooling breeze. So they do use electricity but not as much as air conditioners.
Some use too much, but some have no electricity at all
Those of us living in cities are so used to electricity we take it for granted. We feel a big gap in our lives when the power cuts and loadshedding begins. But actually, a lot of rural India still doesn’t have electricity! More than half of all the houses in India do not have any electricity. According to the 2001 census only 44% of rural households are electrified.
While 99% of villages in Himachal Pradesh are electrified, only 26% of villages in Jharkhand and 50% in Bihar have electricity.
What is perhaps surprising is that the most obvious sign of electricity – lights -- don’t actually use that much electricity. But ordinary incandescent bulbs, because they work by heating a filament inside the bulb, use a lot more energy than do tubelights. And in the long term this energy saving will be noticeable.
TVs too don’t use that much electricity, since energy is just being converted to light in cathode ray tubes. But you don’t use the TV with the sound off, and that’s what uses up most power, the speakers which convert electricity to sound. Computer monitors use just as much as TV sets do and in the long term you can save a lot of power by using LCD screens which use about a third less electricity as compared to the standard cathode ray ones. Computers themselves use tiny amounts of electricity.
But if you don’t switch them off, even these tiny amounts of electricity add up. One of the most wasteful ways we use electricity is the ‘standby’ or ‘sleep’ switch that is found on nearly all entertainment appliances or computers. That’s the little light on your TV or stereo system that stays on when the rest of the device is switched off, ensuring that when you next turn it on you can use the remote without having to turn on the mains switch. These tiny light bulbs and their accompanying circuitry may use little energy but are left on nearly all the time in nearly every home that has TVs. In the UK it was calculated that each year two power stations worth of electricity is wasted by these standby bulbs.
So turn those switches off!
InfoChange News & Features, May 2006