Is the island electricity really free
Looking at that question with a sustainability perspective the answer has to be no the island electricity is_not free.
While there is no fuel cost and all the equipment was donated for the medium to long term one must not forget the upkeep cost of the equipment.
The solar panels & wind turbine can be expected to last 20 + years barring any accident. The batteries however are a different matter. Their life under ideal conditions could be up to 10 years but being more realistic one should budget for replacement over a 5 year cycle.
In the past (some 40 years ago) it was common in the UK for such batteries to be repaired rather then replaced at a cost of around 10 – 15% of a new replacement.
Not sure if battery re-conditioning facilities might exist in Fiji, the process is not exactly difficult.
Full replacement cost of the Vorovoro system batteries would be approx FJ$2500. These batteries are fairly standard 6 volt 200Ah units more commonly used within fork lift trucks etc.
If we assume that reconditioning at 20% replacement cost is possible for the point of initial argument we are looking at an operational cost of FJ$100 / year. Translating that into an on island power usage of 2KWh per day (presently we use approx ½ that but 2KWh /day is within system capacity and allows for future village development)
100/365 = 0.274 therefore each unit (KWh) electricity has a nominal value of FJ$0.137 under optimum recycling conditions.
Moving up to the other end of the scale – outright battery replacement after 5 years – gives:
500/365 = 1.37 giving us a nominal value for the electricity of FJ$0.685 /KWh
Because there is no fuel element to the power supply we do not of course here have a case of use less pay less. I have though used the traditional model of electric power costing in this example to permit better comparison with traditional valuation of electric power. Obviously maintenance costs for the wind turbine & solar panels (+ their eventual replacement costs) will need to be factored in to obtain complete figures for a future business model.
Hopefully though here I have managed to indicate that the “free electricity” is not really free at all.
Comments
Hi John,
What an interesting blog! I assume the environmental cost of manufacturing a long-lasting battery and solar panel is less overall than laying an electricity line/cable, which then uses electricity from hydroelectric, coal, or nuclear sources, which are all damaging to the environment?
Hannah
Hi,
I suppose the cost of repair will depend on the battery.
Older batteries (typically lead acid types) you could replace the battery acid with fresh, and check its density with water with a hydrometer.
(You will have to do this if you notice the battery not retaining charge)
Some newer batteries are fully enclosed so the only option is the dispose / recycle them.
Also the electrode condition might have to be looked at. Usually the cycle of charge and drain should keep them in a fine enough condition but some types of electrodes will completely deteriorate.
Chris
To answer Hannah:
For small scale electricity supply a solar system like on Vorovoro is more economic (both in money & the environment) then laying cables from a central supply source.
However when larger amounts of electricity are needed – like for dishwashers, air conditioners etc the financial saving can rapidly turn negative.
Also for large scale power generation solar cells are far from being “green”
While they are green in use the manufacture of large solar panels uses lots of nasty chemical processes – the residue of which does not really become offset by the “greeness” of the generated power.
To answer Chris:
The batteries are free electrolyte type – not sealed.
They are of standard 6volt 200Ah traction pattern as used in fork lift trucks. There are a total of 4; wired in series parallel
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