Here are some Frequently Asked Questions about
Solar Photovoltaic Systems
How does solar work?
Solar PV system consists of two main parts – Solar Panel & Inverter.
Panels are heart of the system. When placed in sunlight, they generate electricity. The inverter converts this in to usable AC power to run various equipment and appliances.
Inverter is the brain of the system. It automatically synchronizes with the grid. It ensures solar is used as priority over supplied utility power.
Parts of Solar PV system
Solar system consists of the following
1. Solar Panel
3. Mounting Structure
4. Balance of System – Cables – DC & AC, Electrical Fixtures – MCB, RCCB, Surge Protection etc
5. Batteries (only for regions with significant load shedding)
What is the life of solar power system?
Solar panels come with 25 years’ warranty. Inverter warranties are 5-10 years. The mounting structures have 10+ years warranty. Solar PV system is designed for long term operation. You will benefit for at least two decades.
Does solar panel work during monsoon/rains?
Yes. Solar panels need light (not direct sunlight) for it to function.
The system will produce even during monsoon season.
Although the amount of production will be lower than say summer months.
We take this in to account in our modeling.
Example: Countries like Netherlands where it rains throughout the year have successfully installed Solar systems.
What is the maintenance cost of solar electricity system?
Solar PV systems are easy to maintain. All you need is regular cleaning of panels to remove any dust or particulate matter deposits. Nothing else is required.
What is a solar grid tied system?
What we generally offer to customers is a Grid-Tied system. This works in conjunction with grid power. This does not require any batteries.
The inverter output is connected downstream of meter. Therefore the electricity generated by solar reduces the consumption from supplied utility (MSEB for example) power.
For these systems loads are not a limitation. It is possible to run any equipment as surge currents are drawn from the grid supply.
What is solar off-grid system?
Off-grid systems are suitable for places facing significant power cuts. Here batteries are used to store energy to be used in case of unavailability of power.
The system has to be designed considering connected loads and their surge requirement. This typically poses limitation on the size and type of equipment which can be run.
What is solar power net metering? What about electricity requirement during night? How does it work then?
Net metering is an arrangement between the Consumer and the Utility Company where any excess power produced by solar can be exported to the grid. The number of units exported are given as credit. This can be offset when electricity is consumed sometime else (for example in the night).
This has allowed for maximum utilization of Solar Production, even during the days when direct consumption is very low (holidays, etc.).
Net metering arrangement allows credit to be carried forward each month. Only if your production is more than consumption over the period of 1 financial year, you will get compensated by MSEB or utility company.
How much space is required for solar panel installation?
Roughly speaking 1kW of system requires around 100 sq. feet of space. The exact area can be determined only after site survey and shadow assessment.
What is the cost of solar power system?
Cost varies on various factors, for which if you can provide me your electricity bill and let us survey your building, we can give you an estimate based upon that.
What is the payback period for solar installation?
Typically it takes around 3-5 years to recover your money back depending on your tariff. After than you can enjoy the benefits of the system for next 20 years.
What do you need for giving a quotation for solar energy?
We only need a (i) Copy of electricity bill and, (ii) Address for Site Survey.
Is there financing available? Or Solar Finance
We can arrange for loan for solar project. Final approval of course depends on your balance sheet and credit rating.
Interest rate – 11-12%
How long does it take to install solar PV system?
The time for system installation depends on complexity and size of project. This is anywhere from a day to few weeks, depending upon the size and complexity of the project.
Brief description about equipment’s of a Solar PV system.
Solar Panel or Photovoltaic (PV) Module is the heart of a solar system. It consists of multiple solar cells joined together within a aluminium frame and glass casing. When placed in light, cells generate electricity. Solar Panels are rated for their output power. For rooftop system, typically power rating used is 250W or 300W. Multiple panels are put together to generate the desired amount of power. For example if we use 4 panels of 250W we get 1000W or 1kW power. Typically 1kW worth of panels require space of ~ 80 - 100 sq. ft.
Panels are long life item. They last for more than 30 years. Typically we use panels from Tier-1 manufacturers which have output warranty of 25 years.
If panels is the heart of Solar PV system, inverter is the brains. Inverter’s main function is to convert DC power generated by solar panel in to usable AC power (to run our appliances and equipment). It also ensures that Solar power is used in priority over other available forms of power via grid, battery etc
The inverters we use are transformer-less and hence practically silent. They require very little space and can be wall mounted at a convenient location (typically close to solar panels). Inverters are typically warrantied for 5 to 10 years. You can easily expect a working life of around 15 years.
Solar inverters are essentially of following types-
1) Grid Tied
- These are directly connected to the grid supply.
- There is no limitation to the size and type of equipment than can be run
- With net metering, excess power can be exported and used later when required
- Suitable for cases with reliable power supply
- These are connected to specific loads to be run
- These have to be sized based on connected loads and their surge requirement
- Power cannot be exported as mains and loads are isolated
- Suitable for areas with load shedding problem
Inverters are extremely critical to the performance of the system. Hence we only use equipment from European or Taiwanese manufacturers to deliver maximum output.
To get the maximum output, the panels should be facing south at a certain angle depending on the geographic location. The ensure that panels remain fixed to the roof in the desired orientation, mounting structures are used. They have to designed to suit the type of roof. Typically there are two types of mounting structures -
1) Triangular Mount: for flat roofs
2) Flush Mount: for inclined roof
We use mounting structures made of Galvanized Iron or Aluminium to ensure they are able to last long term without any maintenance. This is even more critical in demanding Indian conditions. These structures are warrantied for 10 years.
Our design keeps in mind appropriate provision for access and cleaning of panels in the future.
Balance of System
The remaining part of Solar PV system consists of electrical components such as-
• AC & DC Cable
• Circuit Breakers
• Safety Equipment: RCCB, Surge Protectors, lightening arrestors etc
- SPD (Surge Protection Device) protects the equipment fromfrom surge voltages created during lightening and grid fluctuations.
- RCCB (Residual Current Circuit Breaker) protects against current leaks which may lead to shock or fire.
The electrical equipments have to be designed according to the technical specifications of panel and inverter. It is important to install safety equipments since PV systems are designed for long life. Electrical surges or short circuit can damage the equipment which are much more expensive to replace than standard safety devices.