VIZ-A-VIZ with Hiten G. Parekh, Head, Everest Solar

Q. Roof of commercial buildings and manufacturing facilities in India are usually old and weak, and installing solar panels would affect the life of the roof, what key facets are been looked into before commissioning such critical projects?

For any roof – old or new, it is important to first check the structure stability. As a process, we first get every roof certified by a third party certified chartered structural engineer. S/he evaluates the roof structure and models the roof under software such as Stadt Pro which simulates the dead and dynamic loads and wind loads over the roof. The roof is selected only after a positive report is received from such engineer.

Q. What should be usually the age of the commercial and industrial buildings for rooftop installation?

The age of roof should not be more than 7-8 years since solar systems last for 25-30 yrs.

Q. What type of due diligence is done by the company before installing solar panels on rooftops of commercial buildings and manufacturing facilities?

a. Base load of the facility on weekdays and weekends

b. Interconnection point availability and distance from installation

c. Roof quality and access

d. Direction and tilt of roof

e. Water point

f. Point for placing inverters and junction boxes

g. DG rating and frequency of power cut

Q. Installation of solar panels on the rooftop may cause seepage during heavy rain affecting the highly expensive equipment / important documents inside the commercial buildings or manufacturing facility, how the financial loss due to seepage can be avoided?

All existing roofs are first evaluated for any existing holes. These holes are first fixed with a water proof sealant and then the module installation takes places. While placing the modules, we first try to use as many existing piercings as possible. For all existing and new piercings we use a EPDM rubber sealant that completely prevents any kind of seepage through the holes. Secondly, the piercings are made on the crest portion of the trapezoidal roof. Water tends to collect in the trough portion which doesn’t have any piercings. Lastly, proper water channels are built along the roof periphery to direct the rain water from roof to the ground. Hence, leakage can’t happen owing to solar installation of workmanship is good.

For the long run however, it is suggested that facilities increase their cover through a comprehensive insurance policy.

Q. What are the best practices that developers or installer unusually ignore, resulting in roof leaks and potential hazards from loosened solar panels.

a. Existing holes at the time of installation

b. Physical quality of roof

c. Avoiding use of water sealant rubbers

d. Inefficient designing leading to multiple redundant and unused piercings

Q. How do solar panels affect roof shingles? Does it make it hard to replace the shingles? Should they be replaced before going solar?

Solar should only be installed on metal or RCC roofs and not asbestos or tiled roofs.

Q. The logistical and legal issues associated with installing solar PV on roofs are complex. This is particularly true when owners rent their roofs to solar providers. If not clearly defined by contract, conflict can result over safety provisions, lost income when the panels are removed during roof work, or liability in the event of theft, vandalism or damage. What criteria are followed to avoid these logistical and legal issues and how is the loss covered by the developer?

Firstly a customer is selected only after through credit diligence. This is just like a bank checks the CIBIL rating before approving someone for a home loan. Developers avoid customers with a low credit rating to minimize such legal risks.

Secondly, all developers consider it a material breach of contract if the power buyer doesn’t allow them access at any point through the term of contract. This can even cause parties to go to court.

Next, there is heavy termination payment (penalty) associated with these contracts in case a customer defaults in payments.