Rooftop & Other Services

How does a solar Photovoltaic (PV) power work?

Sunlight (light, not heat) on photovoltaic modules produce direct current (DC) electricity which is converted to alternating current (AC) by a device called an inverter, which is then wired into your main service panel where it feeds your internal power grid.

What are the main components of a solar power system?

Solar modules (panels) and inverters are the main components of a solar power system and they constitute 70% of project cost.

How much area is required to install a rooftop solar system?

1 kWp solar system requires approximately 10 sq. m (or 100 sq. ft) of shadow free area. Therefore, one 1 MWp (1000 kWp) solar system would require 10,000 sq. m / 1,00,000 sq. ft / 3 acres of shadow free area.

What is the cost of a 1 MW solar system?

1 MWp (1000 kWp) solar system would cost around 5-6 crores, including all components, installation and commissioning, delivery and taxes.

What is the installation and commissioning period for a 1 MW solar power plant?

1 MWp (1000 kWp) solar plant would require 3-6 months for installation and commissioning, and typically only 30-45 days of actual work at the site.

Do we need to take any precaution for wind loads?

Yes, wind load is considered. The wind load will depend upon the exact location. The installer should consider IS standards for the specific location. But solar power plants can be designed for any wind load.

What maintenance is required for a solar power plant?

Solar photovoltaic panels have no moving parts, and therefore require little maintenance, which will include module cleaning with water every 2-4 weeks and preventive electrical maintenance every 3 months.

How much electricity will be generated by a 1 MW (1000 kWp) solar plant in one year?

A 1 MW plant will generate around 15 lac units in the first year. The exact power generated will be subject to location of the solar power plant.

Will the energy produced degrade every year?

Yes, the power produced will degrade at 0.5 -0.8 % each year. In the 25th year, the solar system will still produce 80-90% of the energy produced in the 1st year.

What will be the average life of the solar panels?

The solar panels have a warranty for a period of 25 years, however, the projected life is longer.

How does it integrate into the building system?

The evacuation of solar power happens in the LT room, in most cases at 415 V.

What is the difference between solar plant installation on a rooftop versus ground mounting?

Metal rooftop solar system requires 20% lesser area than RCC rooftop solar or ground mount systems. Rooftop solar helps to reduce ambient room temperature by around 2 degree Celsius. Otherwise, both systems are equivalent.

Does the cost vary for installations on rooftop versus ground mount?

The cost of both systems are approximately the same on a per Watt peak (Wp) basis.

How are solar panels mounted on metal rooftops?

Solar panels will be mounted on high-quality aluminum structures, which will be fixed onto the roof sheets.

Is it possible to mount solar panels without drilling holes in the rooftop?

Yes, if the roof sheets belong to the standing seam segment, then solar panels can be installed without penetrating the roof. If not, then penetration is necessary, although precautions are taken to prevent leakage. Installation on RCC roofs does not require any penetration.

Where will inverters be erected?

For installations greater than 1 MW in size, typically, central inverters are used, and these will be set up in a separate room, called the control room. For smaller installations, string inverters are used, and these are erected on the roof or on the factory floor.

Will a roof mounted system damage my roof's warranty?

It will not, as the roofs aren't tampered. Just as screws are used to fix the roof sheets, we use screws to fix the modules.

Will the cost/KWh reduce if the cost of solar panels fall?

Yes. Since 60-70% of cost depends on the solar panel, if there is a fall in the panel cost it, in turn, will reduce CapEx requirement, and this benefit can be passed to the client. But if the cost of other components such as aluminum structures, copper wires which are steadily rising is considered, then the total project cost is more or less stable.

What is likely to happen to solar panel prices in the coming years?

Solar panel prices have declined significantly in the past 5-10 years. This has resulted from a combination of incremental technology improvements, the move to large-scale manufacturing in China, and an overcapacity in the market from 2007 to 2015. However, in mid-2017, module prices had stabilized but have now started increasing as a result of surging demand and various import duties that are levied on them due to geopolitical trade issues worldwide.

What is the price of solar PV panels now?

It depends on the demand-supply model based on global economics. While in India most of the modules are imported, the import duty increases the cost of PV panels, along with the various applicable taxes. So, it’s difficult to predict any cost.

Corporate PPAs

What do you mean by Corporate PPA?

Corporate PPA is a power purchase agreement between a private company and a power producer (developer, independent power producer, or investor) to purchase electricity at a mutually agreed tariff, tenor, and capacity.

What are the types of corporate PPAs in India?

There are three common types of corporate PPAs in India, as follows:

  • For the sale of power from a rooftop solar project
  • For the sale of power from a utility-scale renewable power project
  • For the sale of power from a utility-scale renewable power project structured as a open access project
The corporate buyer must evaluate the available procurement options based on the company’s sustainability and purchasing strategy, the characteristics and location of its electricity demand, local resource availability, and state-level regulations.

Open access

What do you mean by Open Access Power?

Open access power is a regulatory mechanism that allows a grid-connected bulk consumer with a contract demand of 1000 kVA or above to meet a part of or their entire electricity requirements via alternate energy sources.

Which power procurement models can be used in Open Access?

Typically, two procurement models are used: third-party PPAs and captive or group captive models.

Third-Party PPAs

In this model, a third-party investor or Solar developer invests in an Open Access project and sells the power to corporates via a PPA, eliminating upfront investment and Operation & Maintenance (O&M) responsibilities is at the developers end. However, the corporate buyer is liable to pay the Open Access charges incurred from the wheeling of power from the generated site to the buyer’s location.

Captive / Group Captive Model -

In the captive model, the corporate buyer makes an upfront capital investment in the Open Access project. The buyer owns, operates, and maintains the power generating asset. Open access charges are also applicable but unpredictable charges, such as the cross-subsidy surcharge and additional surcharge, are waived off. In addition, the buyer (i.e., the owner of the power generating asset) is also eligible to claim tax benefits through accelerated depreciation. Another variant of the captive model is the group captive model, wherein the Open Access project is developed for collective usage by many corporate buyers. The model is considered group captive if at least one of the corporate buyers holds a minimum of 26% of equity in the project and consumes at least 51% of the power generated.

Group Captive

What is Group Captive Power Procurement Model?

A power asset in which captive buyer(s) consume at least 51% of the generated electricity and own at least 26% of the equity is known as Group Captive Power Procurement Model.

How can a corporate buyer avail the Open Access benefits of a group captive project without completely owning the project?

The corporate buyer must hold at least 26% of the equity while the developer arranges for the rest 74%. A Long-term Power Purchase Agreement (PPA) can be signed on mutually agreed terms between the developer and the buyer. In such a project, the O&M responsibilities are usually passed on to the developer

What are benefits of a group captive project?

For a consumer which doesn’t want to invest 100% of the project cost, a group captive project will provide the lowest landed cost of power with minimum investment, because it is exempted from certain grid charges and particularly Cross Subsidy Surcharge.

While looking at a Group Captive project, what should a corporate buyer do to avoid any risk of being hit with charges and legal challenges?

The corporate buyer should ensure that a Group Captive project is fully compliant with the spirit of the law, and with the Electricity Act and the proposed amendments to the Electricity Rules by following two simple guidelines:

  • Equity participation: A genuine equity contribution, equal to 26% of the equity cost, assuming 70/30 debt to equity ratio
  • Economic participation: Which means paid up equity share capital with full rights such as, value, share of profit/dividends, capital appreciation, voting rights, transfer of shares etc. should be applicable for all shareholders

Is it possible for a corporate buyer to terminate the PPA in a group captive model?

Given the regulatory requirement for the lead captive buyer to own a minimum of 26 percent of the power generating plant, ownership must be transferred to another captive buyer or back to the primary investor if the PPA terminates or expires. Parties typically agree to a put/call option structure to transfer the shares upon expiry/termination of the PPA. If either the captive generator or the buyer is a non-resident or foreign-owned and controlled entity, then subscription/purchase of equity shares as well as subsequent transfer must comply with the Reserve Bank of India’s pricing guidelines.

Wind Solar Hybrid

How is Wind Solar Hybrid (WSH) Open access different from Solar Open access and Wind Open access?

Wind Solar Hybrid (WSH) plants deliver energy from a combination of wind and solar power plants whereas solar and wind open access delivers energy from solar and wind power plants respectively.

What will be the benefits of moving to Wind Solar Hybrid?

Wind Hybrid Plants deliver more energy than standalone solar power plants and wind power plants. Corporates who want continuous and reliable energy for their usage should consider WSH where possible.

Are all open access charges applicable to Wind Solar Hybrid systems?

Open access charges are applicable to Wind Solar Hybrid power procurement. However certain states have given waivers and incentives specifically to Wind Solar Hybrid plants, which makes it an attractive option.

Which power procurement model will be best suited for Wind Solar Hybrid?

Depending on your preference, OPEX, group captive or capex model of power procurement, all options are available.