Solar rooftop: the challenge posed by a shared terrace insidelooknews

Restrictive roof space, shared ownership of the terrace and lack of buy-in from residents make solar adoption in apartments a massive challenge.

For the last two months, N. Balakrishnan, a vendor listed in the PM Surya Ghar scheme, has been waiting to get the “no objection certificate” from a customer in T. Nagar who is keen on investing in a rooftop photovoltaic (RTPV) plant.

“The customer lives in a 14-unit apartment in T. Nagar; he had been inspired to switch to solar power by the example set by his father who has installed a 10 KV solar plant in his independent house. This apartment’s terrace is not being used by residents to dry clothes but it has a water tank and cable lines run over it. Other residents are not ready to allow him to install the solar plant,” says Balakrishnan of Shiva Shakti Solar.

For a basic 3 KV solar plant to be installed, the vendor has to study if the remaining space on the terrace will permit other residents to install a similar facility in the future if they desire. “At least five residents have to agree to it by signing on a form provided by TANGEDCO along with signatures on their Aadhar copy and electricity bill,” says Balakrishnan, adding that he has been called for one more round of talks.

Bigger the number of units in an apartment, the more the challenge in getting personal solar connections installed on the rooftop.

Some years ago, Jeth Nagar Resident Welfare Association in Mandaveli tried installing an RTPV system for common services and consumption but it did not work out for various reasons, one of them being persuading the eight households sharing the roof space to agree to have solar plants installed.

A few years ago, Balakrishnan says, a dealer had to remove the solar plant in a new project as others in the complex objected to having such a facility. In another case in Nanganallur, an owner had a private terrace so it was easy to install the solar plant.

However, he says, in a few cases installing solar plant for one owner has also turned advantageous as other flats in the street wanted to go in for a similar facility.

“Getting consensus from all residents in apartment complexes over adopting rooftop solar power is a tedious process,” agrees Hari Subbish Kumar, senior programme manager, Asar Social Impact Advisors Pvt. Ltd., a partner company in a report prepared by C40 on implementation of solar rooftop in Chennai.

The study says that Chennai accounts for 25% of the electricity consumption in Tamil Nadu but its rooftop solar power contribution is on the lower side. Due to high prevalence of multi-storey buildings and multiple electricity connections in the same building, the progress in rooftop photo voltaic adoption has been slow, says the report.

Absence of a “group net metering regime” in the state was also cited as a hurdle. For tenants, persuading landlords to let them to install rootop solar plant is often a massive challenge.

Hari say they are working with large apartment communities and developers to resolve various teething issues in green energy adoption. Asar along with its partners has also been encouraging RWAs to adopt rooftop solar power for common amenities so that it brings down the maintenance charges for all residents.

Hari adds that many resident welfare associations are not registered under the TN Apartment Ownership Act, preventing them from availing subsidies for rooftop solar plants in common areas.

Change begins on the terrace

From the terrace of John Praveen’s villa, one can see sloped panels stretch away, glinting in the sun. These are John’s neighbours at a gated community in Sholinganallur; and they have gone solar just as John has.

Since June 2023, when he installed a 9.8 KW solar power plant, John has not paid anything towards electricity consumption except for the minimal network charges for a grid-tied solar power system. He is not practising austerity: he is generous with the use of his ACs and various other gadgets.

“Prior to switching to solar power, electricity bills in summer months would hover around ₹20,000 (bi-monthly). Now our bi-monthly bill ranges between ₹ 800 and ₹ 900, which is the basic network charge we are covered under,” says John. The family was inspired to adopt solar power by a school project on affordable and clean energy their son was assigned.

John was also inspired by his father-in-law in Kerala who was an early adopter of solar technology with a solar inverter system.

Switching to solar power has been an immensely satisfying experience for this family of four. Here is the math of it. “Our solar plant has so far generated 27 KWh of electricity, equivalent to 27,000 units annually. The environmental impact, as per the solar inverter app, is significant: 15.4 trees planted (carbon offset equivalent), 27.7 tons of CO₂ reduction and 11.12 tons of coal saved,” he explains.

If a small family like ours can create such an impact, imagine the change we can bring if more households adopt solar energy, he says.

The question of maintenance

Many houses that have invested in rooftop solar plants point out that the key to keeping the electricity bill to a minimal lies in how the panels are maintained.

Many service providers offer annual maintenance contract where the panels are cleaned periodically, and even warranty for five to eight years.

At John’s home, the panels are washed every fortnight with a hose pipe and spray gun to remove any dust and bird droppings. “The panels need to be kept clean for best efficiency,” says John.

T.H. Jothi Kumar, who has a six panel 3 KV plant installed above the lift room of his apartment in Pallikaranai, says before zeroing in on the vendor he read reviews of them. “It is important to not just rely on recent feedback but those written more than five months ago,” says Jothi Kumar. Hard objects such as stones could damage the solar panel and they need to be protected from such things. “Our solar panels come with a lighting arrestor, which safeguards the equipment from voltage spikes, so check if the vendor has provided one or ask for it,” says Jothi Kumar.

R.Balaji, director, GESA Power, an authorised vendor, say they discourage consumers from investing in solar if their bi-monthly bill is less than 400 units.

“We require a minimum of 80-100 sq.ft. space on the terrace to install one kilowatt of solar. If the terrace is not able to accommodate that then we identify other spots where sunlight will be maximum,” says Balaji, an authorised partner for Tata Power Solar.

Other nagging doubts from consumers have to do with metering and the functioning of the solar plant during monsoon. A 3KW solar plant is the basic one can go in for if 600 units is the bimonthly consumption.

“If one installs 1KW of solar it generates 4 units a day and between 5 and 6 units during peak season, which is good enough. Generation happens from 6 a.m. to 6 p.m. and increases during afternoons,” says Balaji.

Tangedco replaces the main EB with bi-directional metres and also charges an amount for this. Stressing on the need to choose an approved vendor, Balaji says under the terms of agreement they are required to serve the customer for five years. “Tangedco can revoke us if a complaint is made by a consumer,” he adds.