As the one who started this thread I thought I'd wade back in to give you an update on what we have achieved & to explain a few things that I have picked up during my research.
Firstly, as I understand it, electricity in Bali is subsidised. There is also a dire shortage of electricity and the situation is bound to get worse as more development happens. As a result, I believe the PLN has taken a policy decision to 'de-subsidise' the electricity and make sure that, particularly, larger users pay their fair share of the true cost of electricity.
So, starting around Feb 2006 the PLN brought in new tarrifs which uses 'Domestic' and a 'Bisnis' rate bands and sub-bands within this which increase as per the size of the supply.
The old rates are being maintained for the time being for existing customers. The new rates apply to new customers. The new 'bands' for Domestic supplies only give a low maximum supply (ie if you turn everything on then the maximum power that you can draw is limited to either 450VA or 900VA). This is probably sufficient for a small local house but is totally insufficient for even a basic 'westener's' house. This means that the locals will not suffer so much from the price hike - which is not unreasonable.
The Bisnis bands give a much larger capacity but they have this millstone of fixed payments per month. Up to 13200VA supply, the fixed rate is not too bad (Rp 1,062,500 giving 1,250KWh per month) but above that the rate is astronomical (Rp 5,185,000 giving 6,100KWh per month). The actual unit rate is the same (Rp 850 per KWh) but the fixed rate is the killer because there is no middle band between 1,250 and 6,100 KWh which is more like where the average 'westerner's' house would fall. You end up paying for power you do not use.
Secondly, on usage and power supply sizes. When you design a power supply for a house you total up all of the power requirements for the items that will draw power including sockets that will not normally be in use. Then you apply a "diversity factor" which accounts for the fact that not all items will be running at the same time and, perhaps, will not have anything in them at all. For my villa, in discussion with my electrical engineer, we used a factor of 60%. I also did some cross-checks to make sure the result was practical - I took a worst case scenario: villa full of guests, getting ready for a dinner in the house in the evening: meaning cookers running, water heaters running, pumps running (for showers), air-con running in the bedrooms, lights on, etc.
Having done all of that, this will determine the minimum amount of power that you will have to get the PLN to supply, obtaining less will mean that the safety cut-outs will trip because you have tried to draw too much power.
Of course, just because you can draw (say) 23,000VA doesn't mean that you will use that amount. I am having a 41,500VA supply installed (more on that later) but only anticipate using around 2,500KWh per month maximum. That is because not everything is running continuously throughout the day. For instance, Bali's climate doesn't really require air-con during the day - a cool breeze in the shade will suffice, even in the 'low-lands' and so air-con may only be needed at night and, even then, not all rooms will be occupied every night; cookers will only be used intermittantly; pool pumps will generally only be run during the day; lights are only on at night; etc.
By way of comparison, I currently live in the Middle East where temperatures are far higher than Bali. I run two 2 ton split air-con units continuously (day and night) throughout the summer and then another 2 ton unit in the evening, plus about the same other equipment that I expect to use in Bali. I use around 3000KWh per month here - I cannot see how Bali will come to more (on average - there may be the odd peak or trough).
Finally, having mentioned the bands above, somehow we have been able to get a supply of 41,500VA (which is a bit more than we need) because we are having to put a larger transformer to serve 3 villas and the smallest that we can get will give us excess supply. We are paying for the installation (which is eye-watering) and the unit rate for the usage is Rp 1,380 per KWh - much higher than the 850 KWh in the 'bands' but we do not have any fixed monthly payment - we pay for what we use, which is an incentive to turn off when possible!
Electricity is expensive in Bali and, it being in short supply, it could be that in time the prices will rise for all consumers, not just the new customers! So, beware!
Hope this is of some use to you all. :idea:
