A lot of excitement has been developing w.r.t Net Metering policy of Solar Power. Net Metering in simple terms is a policy to convert power users into power producers. Here, the idea is that instead of overall bill that a consumer receives, when he installs solar panels on his/her rooftop, the new bill is net of electricity that he uses of grid and units that his/her solar panels supply to Grid.
A simple illustration:
A commercial consumer, who uses 50 Units of electricity daily, goes for Net Metering based solar power solution. The installed solar panels produce 30 Units of electricity daily. So as per net-metering, his daily billing gets reduced to 50-30 = 20 units only.
Further, lets say, on Saturday & Sunday, the commercial office has holiday and he uses only 5 units on these days instead usual 50. But Solar Power has no holiday and it produces 30 Units daily and so for these two days while the generation is 60 Units , consumption is only 10 units. In such case, the extra units gets credited to the user account and balanced off when he uses next. In our cases, on following Monday and Tuesday while he uses grid electricity @30units/day. He is billed only for 10 units as he/she already has 50 Units in his/her account.
This balancing is done for each billing cycle and the new bill, NET BILL is actually total units consumed – solar units produced. Hence, the Net-Metering On-Grid Solar Power system lowers the demand of electricity from the grid and the system will pay for itself over the medium term by significantly lowering electricity costs. Such a system will feed electricity directly into the building’s main/LT panel and result in reduction of annual electricity bill. Excess units are exported back to the grid through net-metering scheme.
A Solar PV Grid Connected System which produce AC power in synchronization with the local grid supply with no energy storage option. A typical Solar PV Grid Connected system consists of following major items-
- Solar PV Modules
- Solar Grid Tie Inverter
Below is the step by step process of how a grid connected solar power system works.
- When sunlight hits the solar photovoltaic (PV) panels, electricity (or ‘solar energy’) is produced.
- The electricity then runs from the solar panels through an inverter. The inverter turns the power from direct current (DC) into alternating current (AC), which can be used to operate any appliance.
- If the appliances in your home are turned on while solar power is being produced, the power runs through the switch board and the solar power is sent to your appliances.
- Any appliances that use AC power can use the solar power. If electrical appliances are switched off or if excess solar power is being produced the power gets sent to the grid which is measured by the energy meter.
Advantage of Net-metering system:
A major benefit of Net metering is the system does not use any battery which means a completely static system with zero maintenance cost. Net metering system for first time are actually zero maintenance system.
Disadvantage of Net-metering system:
As the system does not use any battery so when the grid-power goes off, (coupled with additional technical reasons), the on-grid solar power system also shuts down and so there is no power. Hence, the system has limited use in rural or other areas where there is frequent power cut.