Frequently Asked Questions

A Grid Interactive Rooftop PV system comprises of electrical and electronic equipment such as solar modules, inverters, cables, switch gears, etc. When these components are connected and placed on the roof of buildings exposed to sunlight, the system starts generating electricity. A GRPV system generates electricity that can either be injected directly into the distribution grid or used for captive consumption at installation premises.

Grid Interactive Rooftop Photovoltaic systems are of two types:

  • Systems without battery storage.
  • Systems with battery storage.
  • Cheaper and environment friendly electricity.
  • Excess energy can be fed into the grid with tariff as determined by the State Electricity Regulatory Commissions.
  • Electricity generation occurs at consumption center thus, saving transmission and distribution losses.
  • Lower payback period.
  • Requires minimal maintenance.
  • 25 years guaranteed lifespan of the solar photovoltaic panels.
  • Subsidy is available from MNRE.
  • Highly modular.
  • Quick installation.

No, Grid Interactive Rooftop Photovoltaic systems cannot generate electricity at night. In case of absence of generation by the system, power supply can be availed from the electric grid. Battery can be used to store energy for later use, i.e, night or monsoon.

Under net metering, electricity generated by the Grid Interactive Rooftop Photovoltaic system is first utilized by the consumer to meet their internal/captive requirements and excess electricity, if any, is exported to the grid. Subsequently, when the consumer imports power from the grid, the exports are adjusted against the imports, lowering electricity bill.

Net meter (bi-directional meter) usually records the energy imported from the grid to meet the load and surplus energy exported to the grid after consumption. Both energy import and export are recorded in the net meter. The difference between import and export readings is the actual energy consumed/delivered.

As per UERC, the excess generation being injected into the grid will be settled on net energy basis at the end of each billing cycle.

For each kWp, the Grid Interactive Rooftop Photovoltaic system installed on a south-facing roof will generate four to six units of electricity per day. However, depending upon the weather conditions, the energy generation reduces by around 20 percent for east or west facing roof.

A Grid Interactive Rooftop Photovoltaic system is made up of different components. These include PV modules (groups of PV cells), grid tied inverters, circuit breakers, relays, energy meters (net/gross), module mounting structures (MMS), cables, etc.

The maximum rooftop solar PV and small solar PV plants installed capacity at any Eligible Consumer’s premise shall be up to a maximum of 80% of consumer’s sanctioned load/contract demand.

For Domestic Consumer, installed capacity of rooftop and small solar PV plants shall be irrespective of consumer’s sanctioned load/contract demand.

Also, maximum installed capacity of rooftop PV solar power plant and small solar PV plant at the premises of eligible consumer shall not be more than 1 MW.

Most roofs are strong enough for solar installation without any reinforcement. However, in case of larger systems, it is suggested to consult a qualified Structural Engineer.

As per UERC (Tariff and other Terms of Supply of Electricity from Renewable Energy Sources and Non-Fossil Fuel Based Co-Generating Stations) Regulations, 2018, cost of the Grid Interactive Rooftop Photovoltaic system depending on the size is given in the following table:

Project Size Capital Cost
O&M Expenses for Year of Commissioning
Capacity Utilization Factor
<=10 kW 47,153 1,627 19
10 kW and <=100 kW 43,224 1,448 19
100 kW and <=500 kW 40,612 1,320 19
>500 kW and <=1 MW 39,135 1,230 19

Currently, the following business models are in vogue namely, self-owned (capital expenditure [Capex] model), Renewable Energy Service Company (RESCO) model and third-party owned model. “RESCO” means an energy service company which provides renewable energy to the consumers in the form of electricity.

Capex Model: Consumers develop solar rooftop plant within their premises to own, operate and generate electricity for self-consumption and sell excess electricity to the utility (under net metering) or sell entire electricity to the utility (under gross metering). Generally, self-owned business model is preferred for its simplicity. However, this model also has disadvantages such as high capital cost for the consumer and high technology and performance risk.

RESCO Model: A RESCO builds, owns and operates GRPV plant in the premises of a consumer to generate and sell electricity to the consumer. Consumer may further engage in net metering or gross metering arrangement with DISCOM.

In RESCO, consumer does not invest in the GRPV power plant; instead, a RESCO developer invests and sets up the system. RESCOs are specialized solar developers; they can handle technology and operation risks in a better way. However, RESCO model faces several challenges such as power off-take risks, contractual risks, etc.

Third Party Model: A third party builds, owns and operates GRPV plant on a rooftop and sells the generated electricity directly to DISCOM at Feed-in-Tariff.

Suitability of these models depend on one’s ability to meet the costs. However, RESCO model is more suitable for institutional, commercial and industrial consumers needing higher capex.

Yes. All applications related to Grid Interactive Rooftop Photovoltaic shall be processed through Solar Rooftop Portal – Uttarakhand . Upon submission of DISCOM Application for Interconnection, UPCL will check the technical feasibility and provide a response through the Solar Rooftop Portal – Uttarakhand. Applicants can register themselves through Solar Rooftop Portal – Uttarakhand and apply online directly using relevant forms and formats to the approving authority.

As per Solar Energy Policy of Uttarakhand 2018, all registered companies, firms, institutions, societies, central and state government power generation companies and public/private sector solar power project developers shall be eligible for setting up of solar power project.

A maximum of 1 MW at a single location is allowed under net metering.

No. DISCOM will provide bi-directional energy meters on cost basis for consumers to avail net metering facility.

Energy settlement will be done on monthly basis.

In case of net metering,

The tariff as per the tariff orders of UERC regarding supply of electricity to the consumer by the distribution licensee shall be applicable for net energy supplied by the licensee in the billing period if the electricity supplied by the licensee is more than the energy injected by the rooftop solar power plant of the consumer or the third party. If in a billing period, the electricity supplied by the licensee is less than the energy injected by the Roof-top Solar Plant of the consumer or the third party, the licensee would be billed at a generic tariff as may be specified by the Commission or at a rate discovered through tariff based bidding process whichever is lower for such net energy supplied.

Consumer must comply with the Central Electricity Authority standards and relevant safety standards as followed by EI.

Yes, some banks provide loans especially for solar rooftop systems. This information is available on the Solar Rooftop Portal – Uttarakhand.