Solar Modules and Inverters are the main components of a solar power system and the constitute 70% of the project cost.

PV, short for Photovoltaic, derives its name from the process of converting light ('photo') directly into electricity (‘voltaic’). Simply put, a Solar PV system is a power station that generates electricity from sunlight. The main components of a Solar PV system are:

Solar Panels/Modules: Solar panels consist of a group of small cells made from semiconductor material. When the sun’s light falls on the modules, it excites the electrons, thereby creating direct current (DC).

Storage Battery: The best use of solar energy is to consume it while it is being generated. If the requirement is to store this power and consume it in the non-sunny hours, then solar energy can be stored in batteries for later consumption

Solar Inverter: The DC electricity goes into an inverter that converts it into alternating current (AC). We use AC for running our household or office or factory equipment.

If you planning to install a solar plant, below are some things to consider:

What are your energy demands? How do you consume the power?
What is the availability of the shadow free area in your building?
What is the business model you find more commercially viable (CAPEX or RESCO)
What would be the savings if you go solar?

In grid connected rooftop or small SPV system, the DC power generated from SPV panel is converted to AC power using power conditioning unit and is fed to the grid either of 33 kV/11 kV three phase lines or of 440/220 Volt three/single phase line depending on the capacity of the system installed at institution/commercial establishment or residential complex and the regulatory framework specified for respective States. These systems generate power during the day time which is utilized fully by powering captive loads and feed excess power to the grid as long as grid is available. In case, where solar power is not sufficient due to cloud cover etc., the captive loads are served by drawing power from the grid.

There are basically two investment models to go for solar pv power plant.

1. CAPEX ( Capital Expenditure )

2. RESCO  or OPEX Model

There are two main models:

OPEX Model – In this, the investor owns the asset (Plant). The consumer and the producer enters a PPA (power purchase agreement) for a decided duration of time which is typically 15-25 years. During the tenure of PPA, the consumer pays the producer for the power generated at a decided tariff. After the PPA terminates, the asset is transferred to the consumer.

CAPEX model – In this, end consumer owns the asset (Plant) and can claim accelerated depreciation.

There are various factors involved in choosing your PV system. You might want to research on them before choosing the apt model:
Energy Consumption Pattern
Power Cuts or outages
Various Govt. Policies like Net Metering, Grid Power Access or subsidies on Solar power.

If your roof is not having any shade from any adjacent buildings, trees etc. and its structure is not delicate then your roof is suitable for solar plant. Solar plant can also be installed on car parks, open shade ground within your premises by erecting special mounting structures.

The grid connected rooftop system can work on net metering basis wherein the beneficiary pays to the utility on net meter reading basis only. Alternatively two meters can also be installed to major the export and import of power separately. The mechanism based on gross metering at mutually agreed tariff can also be adopted.

The plant will generate electricity only during the day time so during the night the electricity has to be sourced from the Grid. Secondly, solar electricity will meet only a part of your total electricity requirement, the remainder of which has to be met from the Grid.

Below are the approximate costs for a 100KW set up:

Rs. 65-75 lacs for household sector
Rs. 55-65 lacs for larger commercial & industrial sector
Utility scale is even cheaper owing to economies of scale

It depend about the complexity of the solar rooftop project. Generally it can vary from minimum 2 weeks time to 8 weeks starting from design phase to commissioning of the project.

No permissions are required if you are installing an off-grid solar PV system. But in case you wish to integrate your solar system with grid to avail net metering option, certain permissions are required to be taken from the discoms of your state.

This would depend on various factors such as shading free area available, direction of the roof etc, however as a thumb rule, the following could be a good approximate: 1KW plant requires 12 sq mtrs of shade free area.

On an average, every 1 KW setup produces 1300 to 1500 units in a year. This may however vary based upon the location of the plant, seasonal factors, surroundings and shadow free areas. You can consider 1400 units for sake of calculations.

Most panel manufacturers give warranty of 25 years, however there have been plants in operations for 40 years as well.

The Maintenance is not significant. Water can be used to clean the panels – Typically 5 litres of water is required for a KWh.