According to reports, the blazing sun may be a great way to save on your electricity bill. True, in an apartment building, the roof space — and thus the potential generation — available to each home is limited.
But installing solar devices here to generate power for the common area may be worth it, given that costs are falling.
One reason why many home-owners associations want to put up solar power is the increasing price of electricity.
“Power is already expensive and may go up further. Once a rooftop solar unit is installed, you could get the return on your investment in about six years. After that, the power is free”, says SM Kehair, Board Member of Silver Oaks resident welfare association in the NCR region. Two, the capital expenses needed to set up a rooftop solar unit has reduced. There are many new advanced and efficient solar panels entering the market, says Shashi Kumar B, Senior Vice-President, Design and Engineering, Sobha, a Bengaluru-based property developer.
The new technology units are also low maintenance, besides being cheaper. With nine States — Gujarat, Andhra Pradesh, Uttarakhand, Tamil Nadu, West Bengal, Karnataka, Kerala, Delhi and Punjab — announcing net metering policy, there is no need for local storage of power. “Batteries account for almost 30 per cent of the total system cost”, notes Ashwinder Raj Singh, CEO – Residential Services, JLL India.
Madhya Pradesh, Maharashtra, Karnataka, Tamil Nadu and Haryana offer subsidies of up to 30 per cent on installation of units, and attractive prices for power buyback.
This is in addition to the 15 per cent subsidy already given by the Ministry of New and Renewable Energy (MNRE).
The other advantage is that rooftop solar units, once set up, are practically maintenance-free, barring the periodic need to remove dust, says Sumit Jain, Co-founder & CEO, Commonfloor.com, a property portal.
There are also annual maintenance contracts you can get into, reasonably priced at less than one per cent of the unit cost. The maintenance service will also help you know how the system is performing. For instance, you can get data on how many units are generated daily and take remedial action if the performance is low. The service provider may also give financial guarantee for performance, says Tanya Batra, Senior Marketing Manager, Sunkalp Energy.
If the electricity generated is lower than what’s guaranteed, they will compensate for the shortfall.
To set up a system in your apartment complex, you need a shade-free area to maximise access to sunlight. You would require nearly 100 sq ft per KW of power, says Neha Hiranandani, Director, House of Hiranandani, a developer. It costs around ₹65,000 to install a one KW unit which generates about 4-5 units of power a day. To shortlist a company to set up a solar system, the MNRE’s website www.mnre.gov.in is a good source of information.
The site lists approved channel partners as well as technology specifications for the system. Next, calculate the cost of solar power generation and compare it with grid power cost in your area, since power tariffs vary across States. Ask the company giving the bid to provide an estimate of units that will be generated in a year to work out annual savings.
If you have battery-supported systems, ensure that the distance between the panel and the battery is short to avoid energy loss, advises Singh. It’s best that components such as inverters and wires are of high quality to reduce wear and tear; it could otherwise add to maintenance costs. Rooftop solar units, excluding inverters, have a guaranteed life of 25 years.
The effectiveness of a solar system, however, reduces with age. Singh says that efficiency can drop from 90 per cent in the first ten years to about 80 per cent after that. There are other caveats as well. Deben Moza, Executive Director, Project Management Services at Knight Frank India points out that getting Government subsidy may be difficult.
Systems with power storage may require more maintenance and replacement costs, as the battery and inverters have a life of less than ten years. And given the long 25-year lifespan of the unit, consider if the unit will outlast the building.
“In case the system needs to be shifted, you may have to incur an additional 10-15 per cent of the project cost”, says Batra.