When the above question is asked, it is assumed that the questioner wants to know how solar panels couple together with the inverter to power your home and feed the grid. If you are looking into a highly technical response on how the protons from the sun cause a current to flow in the solar cells, then that will be the topic for another article.
Panel Inverter Home Meters Grid
For a solar PV power system to operate, of course the sun must be up. The sunlight that reaches the panels can be either diffuse or direct or a mixture of both. The term for the quantity of sunlight is called ‘irradiance’. The more irradiance experienced by the panels, the greater the current and the greater the power generated. Panels start generating shortly after dawn and should continue to operate until dusk.
Strangely, solar panels operate best in high irradiance but at low temperatures. Panels are benchmarked at 25oC. At 0oC they generate higher voltage and at 50oC they generate less. Hence, very hot days can cause the output of a solar array to drop off. Cool crisp mornings on a mountain top are ideal for solar arrays and you can often experience power output greater than the nominal output of the system.
The current generated by a solar panel is ‘direct current (DC)’ which is defined as being current (electrons) flowing in one direction only. This is the same as current used in batteries. DC current can be lethal, particularly if the voltage is greater than 120V. DC current can also cause arcing so it’s most important that the DC cables are enclosed in heavy-duty conduit for their run through the roof to the inverter.
The inverter is a box that converts the DC current from the panels into a form suitable for our everyday appliances. This is ‘alternating current (AC). Alternating current flows in two directions in short cycles called waves. Our appliances run at 240V with 50 cycles per second (50Hz).
The AC current, now suitable for use in the home, passes through the switchboard for first consumption by the home. If there’s more energy available than the home can consume, then the excess energy passes out through the meter to the grid where it is available for the consumption of your neighbours.
When a solar power system is installed, the electricity distribution business installs a bi-directional meter which has many registers (memories) for counting kilowatt hours (kWhs). This meter measures peak and off-peak consumption from the grid as well as peak and off-peak export to the grid. You pay for the import and receive payment for the export. The meter measures this data in 30-minute intervals, 24 hours a day, looking at the net import/export in any 30-minute period.
The team of engineers at Energis are experts on the workings of solar panels and would welcome the opportunity to discuss solar PV systems with you. Please contact Energis Pty Ltd on 1300 782 217 to arrange an obligation-free appraisal.