Hi Majid,
when you don't have historical consumption data for your house best you calculate the power consumption and runtime of every electrical device you are using. Most have an info sticker telling the Watts. Example: TV set 120Watt * 7hours, Refrigirator 24h (running approx 10h) * 150Watt, Aircon running 12h * 1000Watt, lights 200W * 7hours......
Try to use LPG (LNG) gas for warmwater heating, cooking etc. instead of expensive electricity.
So you will come up with an daily Kilowatthour (KWH) figure. In winter the sun is lower above the horizon and therefore the full sunshine equivalent hours somewhere 4h/day and higher in summer maybe 6h/day. On the other hand you need less Aircon in winter season.
So whatever your consumption figure is say 30KWH/day you devide by the full sunshine hours per day let's assume 5h/day = 6000 Watt PV panels. This is just an example when you run 5 aircons this figure will be higher, if you use electric fan and no electrical waterheating and cooking the KWH will be much lower.
The const of PV panels is in US (India =
) around 4,50$ per Watt, plus mounting frames, wiring, breaker, charge controller etc... calculate with 6$/Watt.
For my very speculative 6KW big array this would mean around 36,000$.
(alternative 1) If you are connected to the Electricity grid and can use 'net metering' with the Power corp you need a grid intertie inverter which comes to another 7000$ (total average 7$/Watt).
(alternative 2) If you are Off the grid, you need a huge battery bank (5 days buffer * 30KWH = 150KWH) plus some inverters which will be around 20,000$ (total average 9$/Watt).
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This prices are US based estimates for the example of a huge 30KWH/day consumption maybe you need much less maybe more depending on personal lifestyle (especially aircons).
I am living in the Philippines, and when I was looking for a system the local Solar dealer just asked for the double US prices for PV-modules, Windturbines, Inverter, battery... their calculation was a production cost of more than 1$ per KWH compared to 0.14$ from Power corp. I finally get all the equipment myself nearer to market price. But to make it clear my Alternative power is still much costlier than the Government subsidized electricity rates here.
I talked to many people here who are interested in Solar power, but when they heard the cost they were shocked as it is above the cost of building a house here in Philippines.
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I am not sure if you want/can spend so much for Solar energy, or if the purchase of an 10KW Diesel generator to overcome blackouts might be your choice.
