How Solar Power Works
Energy from the sun to money in your pocket
Solar Energy Process
1. Photovoltaic Input:
Light from the sun, or more specifically, photons from the sun (aka solar energy) hit the photovoltaic (PV) array which causes an electric current to be generated. This process is the result of atoms becoming excited, allowing the flow or shifting of electrons to take place within a PV cell. Thousands of these cells are linked together in order to produce more current in the solar module or solar panel. The current generated is direct current or DC.
2. Solar Power Inversion:
DC power means that the flow of charge is unidirectional and that the voltage will not change over time. Alternating current (AC) on the other hand, will reverse direction periodically and change voltage over time. AC electricity is the usable form of electricity for residential (120/240V) and commercial applications (120/208V, 480V, 600V), because of this, we install an inverter to change the current from DC to AC.
But what is an inverter? An inverter is simply a device that transforms direct current into alternating current so you can use the solar energy in your home or business. There are two main types of inverters, string inverters and micro-inverters, each with their own advantages.
String Inverters
-Power is inverted from DC to AC at the ground level, typically requiring only one inverter per residential solar installation.
-Most applicable when the solar panels have unobstructed sunlight and are positioned at the same pitch/tilt.
–The efficiency of the system is dependent on the least effective cell (unless solar array is installed with DC optimizers, see below).
**DC Power Optimizers act like a micro-inverter for string inverter systems. One optimizer is installed under every one or two solar panels, which allow them to operate individually, maximizing their solar energy output if partial shading or tilt/azimuth differences occur.
Micro-Inverters
-Power is inverted from DC to AC at the modular level. Multiple inverters are required and are mounted under the solar panels on the roof.
-Solar panels operate independently so the system remains efficient if minor shading, or pitch/tilt differences occur.
–Allows for expandability of your system over time
3. Electrical Distribution:
Following solar power inversion, the solar panels are connected to a panel board in the home. From here the solar energy is distributed throughout the local loads. The home or business will use the solar energy first, and if required will draw from the grid for any excess energy required.
Strict safety measures under the Canadian Electrical Code must be met. It is important to ensure your solar panel installer is a Master Electrician to guarantee code compliance. Anti-islanding is a safety feature built into the inverters to instantaneously stop feeding the grid during a power outage so electrical workers can operate safely on an uncharged line.
4. Grid-tie in:
Once this is completed, the system will begin to generate usable solar power for the grid. A bi-directional meter is now supplied free of charge to measure your energy imported vs exported. Unused/excess solar energy is sold back to your retailer for a credit equal to your retail rate (~$0.06/kWh). This credit will roll over month by month to be used when the solar panels may not be generating sufficient energy, such as at night or during winter months.
It is possible to develop a solar energy credit during the summer which will roll over throughout the year, negating your power bill completely.
[Off-grid option]:
Off-grid solar power options are available thanks to battery storage systems becoming more efficient. The most notable of these systems is the Tesla Battery which is capable of storing enough power for most residential applications. Numerous other high-quality battery systems are currently available.
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