Ans. Solar energy takes advantage of the sun's rays to generate heat or electricity. It is an infinitely renewable resource and unique for its ability to generate energy in a quiet, clean, and consistent manner.

Ans. Identifying the Solar Power plant size for your domestic or commercial premises depends on the following factors:

1. Wattage of appliances to be run on Solar
2. Monthly energy consumption from these appliances
3. Energy Backup or Days of Autonomy required
4. Roof space available for plant

Based on these factors, the power plant sizing can be accordingly done at your end.

Ans. The useful life of a typical Solar Power plant is considered to be 25 years. This is the duration for which long-term PPAs are signed and financial models are built. However, Solar Power plants can run beyond 25 years while producing a lower output. Many Solar Panel manufacturers guarantee an output of 90% at the end of 10 years and 80% at the end of 25 years.

Ans. Solar powered systems can be categorized in two:

1. Grid connected solar power system.
2. Stand alone Off-grid system.

A grid connected system as the name suggests is the one in which your solar power system is connected to the local main grid. In this case, your loads can run on solar power as long as there is sufficient energy available from the sun during the day. Any deficit is taken care by the main utility supply. However, if the solar energy production is in excess as compared to the load requirement at that moment, the excess energy can be either stored in the batteries (if available) or can be sold back to the utility grid. This difference of energy can be tracked using a meter connected to your Solar PV System.

Ans. In a solar powered system, usually following two types metering systems are involved:

1. Gross metering
2. Net Metering

In gross metering, entire energy generated by the solar PV system is fed back directly into the utility grid. In this case, the owner gets incentives based on feed-in tariffs proportional to the energy fed back to the grid.

However, net metering takes into account the difference of excess energy fed back to the grid and total energy consumed from the grid by the system owner. A detailed explanation about net metering is given below:

Net metering is an agreement that allows the solar PV system owner to sell excess solar energy to the utility company or buy deficit energy from the utility company using a meter to track this energy exchange. Net metering requires a Net Meter that can record both power consumed from, and supplied to, the grid.

It should be noted that without net metering, the excess power generated is still supplied to the grid. The generator doesn't receive any benefit from doing so in the absence of a net metering policy.

Ans. The use of meters in this case differs from State to State. Some states may require only one meter that reads the 'net' energy consumed by the system owner. However, few other states may require two meters -one to measure solar energy generation and the second to measure the units consumed from the utility grid. (Kindly refer your state policy for more information about tariff)

Ans. The 3 most important advantages of net metering are:

A. Financial benefit for the system owner: Since the system owner is charged for the net energy consumed from the utility grid, the owner gets financial benefits. Eg. If energy generation is less than energy consumed: owner pays just for the net amount. If energy generation is more than energy consumed: the owner gets credit for excess generation.

B. Avoid the use of batteries: In a grid connected Solar PV System, any excess energy generated can be fed back to local utility grid and can be taken back at later stage when required. Thus, there is no need to store the surplus energy in batteries for later use, thus, avoiding the heavy costs of batteries. Also, since batteries are eliminated, the maintenance costs of the system also reduce to a great extent. Please note, in a Battery-less grid connected system, if there is a power outage and the grid fails, your solar power system has to stop generating power to ensure safety of the wiremen working on the failed gridlines.

C. Produce more today, use that tomorrow: Typically, a solar power system produces more energy in summer and comparatively less energy in winter. Eg. If in summer, solar power generates 100 units and load requirement is 80 units, then 20 units can be fed back to the grid. In winter, solar power generates only 60 units and load requirement is 80 units, then 20 units can be taken from the grid. Thus, overall excess generation from solar power system is taken care of and net units consumed from the grid become zero.

Ans. There are a few states in India that have implemented Net Metering policy. Some of them are: Tamil Nadu, Karnataka, Andhra Pradesh, West Bengal and Uttarakhand. Many more states are in process of setting up their policies.