Alternate Power Supply: Should You Buy a Generator or a UPS?

After just a few months of the Pakistani government's promised 'no load-shedding,' schedule power cuts are back and likely here to stay. There are three ways you can provide an alternate power supply to your home or office: UPS, petrol powered generators or gas powered generators.

Uninterruptible Power Supply (UPS)

A UPS basically works like a battery back-up. It stores energy while your power is on, and uses it when your power supply shuts off. Buying a UPS is usually cheaper than buying a generator. The UPS doesn't make any noise and it turns on and off automatically. The only drawback of a UPS is that if power cuts are excessive, they don't have sufficient time to charge before the next cut. When there were 12 hours of load-shedding per day in the summer of 2008, UPS machines could not keep up.

A 500-watt UPS that can power 2 fans and 2 fluorescent tube lights costs around 8,000 rupees ($100). The battery to attach to it costs around 6,000 rupees ($75), making the total cost 14,000 rupees ($175). A 1000-watt Chinese model UPS is going for 11,000 rupees ($137.50) plus the cost of the battery. With 1000 watts, you can power 4 fans and 4 fluorescent tube lights. The UPS will be wired inside your home, so you won't need to go outside the house to operate it when the power goes out.

Power Generators

For 9,000 rupees ($112.50), you can buy a 1 KVA (kilovolt amp) that can power 3 fans and 3 fluorescent tube lights. For 28,000 rupees ($350), you can purchase a 5 KVA generator that can power one air conditioner along with a few lights. You can also purchase generators that are more than 5 KVA if you buy an industrial size one.

One downside of generators is that they must be turned on and off manually. When the power goes out, you must first shut off your main power supply. Then you must go outside and turn on the generator. As the generator does not turn off automatically, you must keep track of the time and guess when your regular power supply will return. If you forget about the generator, it will run for hours and potentially damage the machine. When you want to turn your generator off, you must go outside and power down the machine. Only after the machine is off can you turn on your main power supply. Failure to turn off the generator before turning on the main power supply will send the current directly into the generator and ruin it.

Gas generators cost less to run than petrol powered generators but are incredibly noisy. Running one at late hours will certainly deprive your neighbors, and possibly even you of sleep. Generators create more noise pollution and air pollution than a UPS. They are also more of a hassle to work and are more likely to need maintenance. That said, if you want to run ACs and lots of appliances when your power is off, the only way to do that is with a generator.

The prices listed in this article are from the 2008 models being sold in Spring 2009. As new models enter the market, load-shedding increases, and the temperature rises, you can expect prices to go up as well.

Sources:

The News - March 21, 2009
Uninterruptible Power Supply
Author's experience