A Solar rooftop PV system is a photovoltaic system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. The various components of such a system include photovoltaic modules, mounting systems, cables, solar inverters and other electrical accessories. Rooftop mounted systems are small compared to ground-mounted photovoltaic power stations with capacities in the megawatt range. Rooftop PV systems on residential buildings typically feature a capacity of about 5 to 20 kilowatts (kW), while those mounted on commercial buildings often reach 100 kilowatts or more.


The urban environment provides a large amount of empty rooftop spaces and can inherently avoid the potential land use and environmental concerns. Estimating rooftop solar insolation is a multi-faceted process, as insolation values in rooftops are impacted by the following:

  • Time of the year
  • Weather conditions
  • Shading from adjacent buildings
  • Shading from overhanging vegetation
  • Roof slope
  • Roof aspect
  • Shading from adjacent buildings and trees

Business Models for Solar Rooftop Development

Typically there are two business models prevailing in the market which includes installing your own solar PV system and in other business model a THIRD PARTY developer owns , operate and maintains the roof top solar PV system and the home owner/ consumer pays for the electricity which it purchases  from the roof top system installer. The third party owned roof top system sometimes allows consumer to receive electricity at a lower price than grid electricity. [/ezcol_1half] However, it doesn’t allow home owners to avail certain financial benefits such as tax benefits and capital subsidy associated with the installation of the roof top systems.  A typical 5 KW roof top system costs about 5 lakh rupees however, the government provides a 30% capital subsidy and accelerated appreciation benefits which makes the investment cheaper and the electricity is available to the consumer at a price of about 5 -6 per unit. However, if the same system is installed by a third party on build, own and operate basis a PPA is signed between the roof top leasing agency and the home owner. Although the financial and capital subsidies are enjoyed by the roof top system installer the cost of electricity is typically about Rs. 7 per unit which is sometimes at par or little higher than the grid electricity.


Future Prospects

India is working on a plan to form an association of countries with high solar power potential, aimed at lowering the cost of solar energy and improving the country’s standing at the global climate change and environment protection discussions. The proposal aims to bring together 56 countries with more than 300 days of good solar radiation. The move follows India substantially revising an earlier target of achieving 20,000 megawatts (MW) solar power capacity by 2022 to 100,000MW, requiring an investment of around Rs.6.5 trillion over five years. IMG_2205

PV modules selection and sizing

Inverter selection & sizing

Economy of Roof top Solar System



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