Roof top Solar for domestic needs @ Bangalore - can I do it today?

A chance conversation with an acquaintance who works at a Solar Energy firm gave me a picture of the possibilities that await us. Now, I do read Solar Power/Panel Blogs/Forums etc once in a while, and have some idea of developments in the area. But I, like many of you I am sure, don't know much about the exact options available for me to try solar power here in Bangalore as an option to reduce my dependency on the Government's unreliable Power Grid.

What do I want to know? Here is a list.

• Daytime needs - Solar Power as primary source, and BESCOM only as a backup
• Night - If practically possible, some solution would be good , but not really a need, BESCOM for night and Surya Maami for the day is perfectly fine.
• Community grid/pooling - I am told it may not be possible to run high wattage appliances on solar power. If every house in my community decides to go Solar, and if we make a local area grid, can this "pooling" serve the variable power needs of the community?
• Price - Life of one time Investments that are needed, and Savings expected
• Surface area requirements - how much needed for typical household needs (4-5 Kw)
• Last, what are the government incentives for a consumer like me, or my community to go Solar!?

When I think Solar, either those water heaters come to mind, or the various rural market focused products (lanterns, cookers etc). Why isn't there enough push for urban or regular consumer applications?

Some data points I get are like this

• Need about 80 square feet area for 1 Kw worth power
• Cost for this may be about Rs 3 lakhs
• Whatever is required to integrate Solar supply with Government grid (BESCOM) so that Solar would be primary and BESCOM only for backup or variable needs exists, and is most likely included in the above price estimates
• Panels last for 25-30 years.

Adding it all up, let us see what is practical or possible right now

• For 5 Kw worth power, I would require 400 sqft of roof space.
• Appx cost would be 15 lakhs, I assume including some batteries/inverter/charge controller etc.
• Assume that this would serve me for 15 years, and I would be using BESCOM for 50% of my needs
• 1000 Rs Electricity bill would be cut to half, Rs 500 saved per month.
• 6000 an year, 9 lakhs over 15 years at today's costs. And I am not including annual maintenance costs, simply because I don't know!

Do the numbers above look right?

The two answers I don't have are:

• If a community of 500 families join in, does the cost/benefit equation change in anyway?
• I bet government will have incentives for communities too? What exactly do they have, and does it change the cost/benefit equation significantly?

So then, please add and correct if you know more.Won't we really like to explore this emerging environment friendly possibility!?

cheers,

SB aka Pranav

PS: Image above is sourced from Partha Das Sharma's blog