Photovoltaics and How Solar Works
Solar Electricity is also known as Photovoltaics (PV). PV systems provide electricity for buildings such as homes, offices, factories, and utilities through panels (Photovoltaics modules) mounted on the ground or on rooftops.
Solar energy is a renewable source of energy. It can be used to produce electricity as long as the sun rises in the morning. As long as we are alive, we will always see the sun, which means it is infinite. This unlimited energy source can be harnessed by installing a solar electric system and creating your own power plant to supply your energy needs.
How Photovoltaics Work
• Sunshines on the photovoltaic modules and produces a flow of electrons that the system converts into Direct Current electricity.
• Direct Current electricity is fed into a solar inverter that converts Direct Current into Alternating Current electricity. Alternating Current electricity is used to power your home and all of your appliances.
• The inverter is wired to a utility that requires a disconnect into your main electrical panel that feeds electricity into your home. If there is an immediate need for electricity as it is being produced, the home uses solar power directly.
• Any electricity not required by your home goes back into the utilities main power grid for others to use or stored in a battery bank for future use. In states with Net Metering, your meter will run backward, and the utility will credit your bill for the excess energy sent back to the grid.
• The utilities main power grid acts as a “bank” or “battery” – excess power is exported to the main grid when you do not need it, and you take power back from the grid when needed (nighttime).
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Components of Photovoltaics
Photovoltaic Modules (Panels)
Solar modules are typically made of many solar cells wired together. Solar cells are tile-sized silicone wafers, wired together and encased in protective glass and metal frame to create a module. They often have a blue or black appearance. Most solar modules installed today are either Monocrystalline or Polycrystalline.
Monocrystalline Photovoltaics –
Monocrystalline modules are the oldest and most developed technology. Monocrystalline modules can be identified by solar cells which all appear as a single flat color – typically black. Monocrystalline modules have the highest efficiency rates since they are made out of the highest-grade silicon. The efficiency rates of monocrystalline solar panels are typically 15-20%.
Polycrystalline Photovoltaics –
The first solar panels based on polycrystalline silicon, which also is known as polysilicon (p-Si) and multi-crystalline silicon (mc-Si), were introduced to the market in 1981. The process used to make polycrystalline silicon is simpler and costs less. The amount of waste silicon is less compared to monocrystalline.
Polycrystalline solar panels tend to have slightly lower heat tolerance than monocrystalline solar panels. This technically means that they perform slightly worse than monocrystalline solar panels in high temperatures. Heat can affect the performance of solar panels and shorten their lifespans. However, this effect is minor, and most homeowners do not need to take it into account.
Inverters play a crucial role in any solar energy system and are often considered to be the brains of a project. An inverter’s basic function is to “invert” the direct current (DC) electric produced by the photovoltaics into alternating current (AC) electricity. AC is the standard used in all homes and the inverter converts the electricity so it can be used in the home or sent back onto the utility grid for others to use.
Types of Inverters
• String Inverter
• Hybrid/Battery Based Inverter
Electrical (panel, disconnects)
To transfer the electricity produced from the Photovoltaic solar modules to the home to use or onto the utility grid requires installing several electrical components. After the energy is passed from the module and converted to AC by the inverter, the power feeds into a utility-required disconnect. The disconnect is required by all utility companies and is installed near the utility meter. The disconnect allows the utility to shut down the solar system at any time so work can be performed on the main power lines without the system feeding energy onto the grid.
The solar electricity is routed to a back-feed breaker in the home’s main electrical panel from the disconnect. This allows the home to use the solar energy produced to run the current energy needs of the home. If the home needs more power than the solar can produce, the additional power is consumed from the grid and the solar power. If excess power is generated over the home’s current needs, the excess power is fed back onto the utility power grid and used by others. In states with net metering, this excess energy can be credited to the home’s electric bill.
For states without net metering, the excess energy produced can be fed into a battery backup system and stored for future use.
Experienced and certified electricians complete all electrical work performed for Sun City Solar installations. In addition, sun City will acquire any needed city/county permits and ensure the project passes inspection.
Utility smart meter
After the solar installation is complete and all inspections have been completed, most utilities will install either a net meter or a bi-directional meter to replace the current utility meter on the home. Net meters show the net consumption of power in the household. A net meter does not tell you how much solar electricity you pushed out to the grid or how much “regular electricity” you took from the grid. Instead, it indicates the difference between the two, or the “net usage.”
Bi-directional meters have three display screens. One is a test screen where all lights are on. The second shows power coming in from the grid, and the third shows power going out from your solar into the grid.
A monitoring system for your solar array ensures that everything is operating efficiently and alerts you to any problems that may arise. A monitoring system will ensure you are getting the most out of your solar investment by allowing you to make sure the system is operating as designed and intended. For example, if a module or inverter stops working properly, the monitoring system will show an error alerting the owner to a potential issue. It allows the error to be diagnosed and fixed quickly to ensure minimal downtime and lost production with real-time error alerts.
Monitoring systems installed by Sun City Solar allow a solar owner to have detailed real-time information on their system through both a smartphone app and a web-based site. Detailed information includes current energy production and detailed historical production on a daily/weekly/monthly basis.
To view the solar production details online, the monitoring system must be connected to the internet.