Building Construction, Renovation, Maintenance & Advice

Backup and Emergency Power Supply

"Home Made Electrons"

On those many occasions when the National Power Company (PLN) decide to switch off your electric power without warning it can be a real pain in the artistic part of the day. Bali’s electrons are sent down the wires from a power station on the north coast of Java well on the way to Surabaya. It is a long way for those poor little electrons and by the time they have got here they have run out of puff.

In recent months “maintenance” has further reduced capacity at the power station and, as a final nail in the power supply coffin, heavy seas mean that barges have not been able to deliver coal from Kalimantan. These facts combined with the “unofficial” consumers of electricity that overload the Island’s electrical grid mean that our power supply is critical and we all have to be rationed.

It is all rather tragic really especially as Indonesia is probably one of the most suitable countries in the world for geothermal power. Still we must keep the coal and gas contracts going mustn’t we and, after all, global warming is helping the Eskimos avoid frostbite.

Somewhere in a hidden office in the depths of Denpasar Gregory, a little man with a furrowed brow, dishes out the electrons, “one for you and one for you, one for you and…..” It’s a laborious task and he struggles to keep up so he has to switch a few houses off every now and again just to give him time to have a little wee or go and make a cup of cocoa.

Meanwhile back home you are just finishing that urgent report for tomorrow on your computer. You have been so busy you didn’t remember to save it for the last 4 hours.

Splut, everything goes dark and you see the last of a particularly well worded couple of paragraphs disappearing up the computer screen’s nether regions.
The cat meows and rubs itself across your legs moments before it goes for a short flight across the room and gravity becomes an interesting concept leaving scratch marks down the wall.

So what can we do?

Well of course if it is only the computer you worry about you can get yourself a UPS (uninterrupted power supply) which will give you a squeal of warning when denied it's electrical power source and those precious minutes you need to save your masterpiece.

There are other solutions. Perhaps you could use a manual typewriter and an abacus?
It was just a thought.....

A good friend who owns a spa has recently been rubbing his hands in glee at the thought of his new business direction. - Japanese tourists. They come in bus loads, partake of his excellent services and depart leaving behind a rather handsome wad of the folding stuff.

My friend, however, has one major worry that gives him sleepless nights.

If Gregory stays too long at the toilet and doesn’t send a meagre few electrons down the line our Japanese visitors are going to suddenly find themselves in the dark and only half “done”. Those Japanese won’t mess around. Contracts will be lost and my good friend will have to fall on his sword for the sake of international relations (and by sake I am not talking about some sort of mind numbing rice based distillate).

He must have his electrons and, in the absence of a reliable supply, he has decided to make his own. There are several advantages. Home made electrons are usually of far highly quality than those mass produced ones. They haven’t travelled half way across the world to get to you so they are usually pretty healthy to say nothing of the fact that you can make them as and when you need them.

In short my aforementioned friend has decided to install a generator so he can sleep at night.

Electric Generators or Gensets

Generators come in a wide range of sizes and specifications so where do we start?

Selecting a Generator

First we have to determine how much power we need and, of course, the smaller the generator the lower the cost both to buy and to run. You need to think carefully whether you can switch some equipment off should the power fail thereby reducing the amount of power you need to generate.

Peak Load

You also need to consider “peak” load. Peak load is the maximum you may use at any one time and for most households and businesses with many items switching themselves on and off this is random so that probability (or is it sod’s law?) says that every now and again many things will switch on at around the same time and you have a sudden dramatic increase in power demand giving you a “peak” that your supply somehow has to be able to satisfy.

By careful management you can keep the peak load down. You can make sure that someone doesn’t start using a microwave while the toaster is switched on. By putting a timer on the electric water heater you can heat your water at times when other things such as air conditioners are not running. There are many things you can do.

Generator Size

Generators are sized in KVA (Kilo Volt Amps) but be careful, because of a little know and even lesser understood phenomenon known as power factor (the efficiency of the generator) the rating in KVA is not the same as the power output in Kilowatts. A 35 KVA generator will generally deliver around 25 kilowatts of power.

My friend’s establishment at present has a 3 phase power supply of 22,000 watts. His demand is for air conditioners, pumps and heaters leaving little opportunity to reduce the power he needs to keep his business going if the PLN supply cuts out.

Single Phase or 3 phase

Generators come in either single phase or 3 phase and this should match your own supply so that the generator can simply cut in and supply the same circuits.

Noise and Silent Type

Generators also come as open or silent type. Silent type means the generator is mounted in a sealed steel box which considerably reduces the noise it makes. Generators can be very noisy things. Remember the noise at a fairground or a circus? All caused by diesel generators to drive the roundabouts and lights.


Vibration is another important consideration. A silent generator will still vibrate and the vibrations going through building foundations will be felt right through the building. I suppose our friend could persuade his Japanese guests that the vibration is part of the treatment but insulated vibration absorbing pads may be a better idea to keep his business going normally. Brain surgeons, for instance, do not like operating next door to large generators – it has a tendency to create madness.

Petrol Diesel or Gas?

Next consider what sort of engine you require. You can get petrol, diesel, gas powered engines, water powered and these days wind generators. A water cooled engine will be a lot quieter than an air cooled generator.

Some people prefer a generator that will go forever with minimum maintenance and the old solid Perkins, Lister and Cummings engines fit this bill but can be expensive. Japanese engines such as Mitsubishi and Yanmar are good engines, they are usually lighter and cheaper but not as durable.

If you only want small amounts of power you might consider photo voltaic cells or a wind generator. You will need batteries to store the power to cover the times when the sun is not shining or the wind dies but can be very useful in the right circumstances.

Automatic Start

If you decide to install and electric generator you will also probably need an automatic starter which detects when the mains supply is cut and automatically starts the generator. If you want to go off and find your shoes and crawl into the back garden on a dark rainy night to start your generator that’s alright you won’t need an automatic starter circuit.

Voltage Stabiliser

You will also probably need a voltage stabiliser for your mains supply because when the voltage drops (as it does frequently in Bali) it can confuse and even possibly damage the automatic starter.

How does a generator compare with PLN for cost of power? There are many factors to consider to come to any meaningful figure and in addition to the fuel cost you must cover the purchase cost of the generator and equipment, servicing and maintenance costs for the generator and the time taken to check it and test it on a regular basis. The answer put simply is “considerably more than PLN” I am afraid and a generator can be very inefficient. If you have a large generator running that is capable of driving your swimming pool pumps or a water heater remember that large machine still has to run when you only need one light on.

If, on the other hand, the reputation and survival of your business depends on how long Gregory spends on the tut then a generator may be just the answer you need.

Copyright © Phil Wilson 2009
This article or any part of it cannot be copied or reproduced without permission from the copyright owner.

17 July 2017 Copyright © Mr Fixit,
Jl Bypass Ngurah Rai, Gg Penyu No 1, Sanur, Bali 80228, Indonesia
Telephone: +62-361-288-789, Fax:+62-361-284-180