GO GREEN: Bescom 's new initiative lets you have solar panels to electrify your house and sell the excess power back to the utility. But is the investment worth it?The net-metering concept, introduced by Bescom earlier this year, allows any consumer who has solar panels installed at his residence to sync with Bescom's grid and feed any excess electricity generated back to the grid after their home requirements are met. It's a simple dual-meter system, where both your input and intake are measured. So, when you sign up for the programme, in addition to the meter that already records your monthly consumption another meter is fixed to record your monthly solar-electricity production. At the end of the every billing cycle Bescom buys back the excess produced."Under the scheme, customers can both import electricity from the grid and export excess electricity after self-consumption. While the maximum they pay per unit is Rs 5.50 per unit, they gets back Rs 9.56 for per unit produced," says Pankaj Kumar Pandey , MD, Bescom. So, even if you do not produce more than your consumption and it's a Rs net import', you still get a discount as the units produced gets deducted from your total consumption.The only criteria to enter into a power purchase agreement with the electricity supply company is that you should have roof rights and the space to install at least a basic 1KW solar panel system. Open terrace areas can also be used wherein solar panels are placed atop canopies, or module mounting structures."For individual home owners, a 10ft x 10ft shadow-free roof space, is sufficient for a 1 KW system that can generate around 4 to 5 units of electricity per day in Bengaluru ," says Ratnadip Bhattacharjee , CEO and Director, ArrayTech Technologies, a Beng alur u-based solar panel provider.So far, 122 customers have signed up for the programme of which more than 100 are individuals. " Apart from residents, some have applied for the Solar Roof-Top PV scheme for commercial spaces as well," says Pandey .The scheme is good for the environment and being promoted by the government. The Karnataka government recently announced solar PV systems to be VAT-free and you get electricity at a discounted rate if you are a producer . However, the capital required to install a solar panel system is high.Even the smallest 1 KW solar system, which can be put up on 100 sqft terrace or rooftop area, the cost around Rs 1 lakh along with another Rs 3000-4,000 for the second meter. The bigger ones of around 5KW capacity can cost up to Rs 5 to 6 lakh. However, since the system is a one-time cost that has an average life-span of 25 years, it is being sold as a green-investment that has a potential to generate returns over the years.But is it so?COST VS BENEFITThe average monthly electricity consumption of a 2BHK in Bengaluru is around 200 units.This means, you would need at least a 1.52 KW Solar PV system that produces around 230-250 units per month, depending on the weather conditions, to be a Rs net exporter'.Generation capacity may decli ne during heavy downpour duration, typically for an hour or two during monsoon season.However, electricity is generated using daylight, which means they work even on cloudy days."Bengaluru gets about 300 days of sunlight in a year, which is highly conducive for solar power generation," says Bhattacharjee. So, you can produce electricity round the year.This system will cost around Rs 2 lakh. There are no recurring costs as the life of the panels is 25 years and you do not need batteries to store the energy as you are directly connected to the grid.Now, consider this: A 2 KW of solar PV can produce 10 units per sunny day , meaning 3,000 units per year.Assuming you consume 200 units, you are consuming 2,400 kWh per year, an excess of 600 units. The average cost of electric ity is Rs 3.8 per unit (Bescom charges any thing between Rs 2Rs 5.50 per unit, depending on your usage). So, you are saving Rs 9,120 as electricity bill and making Rs 5,736 from selling the excess to Bescom for Rs 9.56 per unit. Meaning, an annual saving of Rs 14,856. At this rate, it will take you 13.4 years to simply break-even your initial capital in vestment of Rs 2 lakh.Even, if you invest the yearly savings and earn 8% return on it, it will take at least 9.5 years to recover costs. In the remain ing 15.5 years of the life of the plant, the yearly savings will generate merely Rs 4.22 lakh for you.The only way to make the returns look significant is to install a bigger systems, 5 to 10 KW capaci ty systems (see table). But then, looking at the current real-estate prices and the shrinking apartment sizes, not many have the luxury of a 500 sq.ft. of free roof space these days.