Photovoltaic Energy Systems
Want to install a photovoltaic Energy System on your home or business in Redding? Learn all about how it works here.
What is a solar panel?
A solar panel (also known as a photovoltaic panel) is equipment that converts light from the Sun into a electric current.
Is The are three common types of solar-electric systems commonly used. They are grid-intertied, grid-intertied with battery backup, and off-grid (stand-alone). Each has distinct applications and component needs.
Grid Intertied Solar-Electric Systems
This type of system feeds excess electricity back to the grid and saves you money on your power bill directly. When your solar system doesn't generate enough power for your home, power flows in from PG&E and when you have an excess of power, it flows back into the grid to help power other homes in your area. PG&E has good information specifics about how net metering works when you install a solar energy system in your home. Most utilities across the country have some sort of net metering or net billing option available for people who install solar systems. Some utilities will even purchase excess electricity generated in some states.
Here's how it works
1. Photovoltaic panels generate electricity.
2. Electricity is converted to household current (AC) for use.
3 Extra Electricity goes through the Utility Meter effectively turning it backwards.
For additional information visit Homepower magazine website and read the following articles:
Energy Smarts-Efficiency Gains + Solar Electricity
Creating A Brighter Future
Getting Off the Lifetime Utility Payment Plan: Grid-Connected PV
Grid-Intertied Solar-Electric Systems with Battery Backup
The battery backup system is designed to store extra power generated by the photovoltaic solar system in batteries on site and once the batteries are fully charged, the excess goes into the power grid. This system is nearly identical to the Grid Intertied system discussed above, except that a large bank of batteries are included to store energy for those days when there is not electricity being produced by the solar panels. This type of system costs more money but is a more reliable source of energy when the sun is not shining. It is ideal for homeowners who experience utility outages regularly and must have electricity to help power their house.
Here's how it works.
For more information on battery backup solar powered homes read the following articles from the home power magazine website.
Photovoltaic panels generate electricity
Electricity is stored in batteries on site.
Energy needed to power the house comes from the energy stored in the batteries.
Once the batteries are fully charged, excess electricity is fed into the grid.
Eight Years of Solar Electricity: and Counting...
Walking the Talk: Energy Group Gets Solarized
Off-Grid Solar-Electric Systems
The last type of solar electric system is most common when there is no utility service available. These systems can work anywhere. They work independent of the power grid and provide all of the electricity to power your home. They also require additional batteries to store more electricity for extended periods of non-solar activity. Off grid solar electric systems tend to be more expensive but are very reliable. People who use these types of systems learned to become very energy efficient in their use of electricity.
Here are some additional articles from the home power magazine website about off grid solar electric systems:
Postmodern PV Pioneers
Solar Comfort in the Idaho Wilderness: Off-Grid PV
All Creatures Under the Sun—My Solar Powered Barn
Green Half-Acre: Off-Grid Country Living – In the City
Photovoltaic System Components
the basic components of a photovoltaic electric system are the solar panels and the racks that support them, a DC disconnect switch, the charge controller, the Bank of batteries, the system meter, a main disconnect, and inverter, the AC breaker panel, the kilowatt hour meter, and optionally a backup generator. Here's what each of these components does:
The solar panels generate the electricity, converting photons of light into energy and feeding them through the disconnect switch to the charge controller. Solar panels come in many shapes and sizes, but are usually designed to be rackmounted replaced on the roof of a home. The larger the solar panel and more electricity can produce. The photovoltaic panels have become very reliable and often come with up to a 25 year warranty. Solar panels are also known as solar electric modules or photovoltaic panels. Click on how solar panels work to learn more.
The DC disconnect switch is an important safety component of your solar panel system. The purpose of the switch is to safely interrupt the flow of electricity from the panels whenever system maintenance or troubleshooting is necessary. It is basically an electric panel with a large shutoff switch and it may be integrated with circuit breakers or fuses if needed.
The DC disconnect is used to safely interrupt the flow of electricity from the PV array. It´s an essential component when system maintenance or troubleshooting is required. The disconnect enclosure houses an electrical switch rated for use in DC circuits. It also may integrate either circuit breakers or fuses, if needed.
The purpose of the charge controller is to turn off the power to the batteriesonce they are fully charged. The charge controller is designed to protect your batteries from overcharging. Batteries are one of the most expensive parts of your system and its important to take proper care of them and not over charge or under charge them. They may lose their energy storing potential if not monitored properly. The charge controller prolongs the life of your batteries and is an integral part of the system. and constantly monitor the battery bank.In the batteries are fully chargedthe controllerstops the flow of electricityfrom the photovoltaic panels.The charge controllerhelps protectthe expensive batteries in your system..butthe charge controllercan interruptthe supply of energy from the panels to the batteriesand divert itto the gridif it is a system that is tied in with the power grid. .
The battery bank is a group of batteries that are tied together to store energy so that you can have electricity at night time when the sun is not shining. Battery backups are usually used in a photovoltaic system that is off the grid. The size of the battery bank depends on the household electricity needed and is usually sized to last for one to three days of cloudy weather. Batteries used in a photovoltaic system are specialized batteries capable of being charged and recharged and discharged on a regular basis with a high-capacity of electricity available for use.
The system meter measures different aspects of your solar electric systems status including tracking how full your battery and bank is, how much electricity the panels are producing and how much electricity you are using at any point in time. The system meter is a critical part of your photovoltaic system.
The inverter transforms the DC electricity produced by the solar panels into alternating current that is most commonly used by households. If your system happens to be tied to the grid the inverter will synchronize the electricity produced with the panels with the electricity that exists on the grid. .
The main DC disconnect switch allows for the inverter to be disconnected from the batteries for service and maintenance. It is mountedin a sheet-metal enclosure and protects the inverter to battery wiring against electric fires.
The AC breaker panel and inverter DC disconnect are the panels where all of the electrical wiring for the solar generation system meets with the utility electricity. It is a wall-mounted panel which is located near the solar panels on an off grid installation or near the electrical meter of the house where the utility connects to the circuit breakers for the house.
AC Breaker Panel & Inverter AC Disconnect
AKA: mains panel, breaker box, fuse box
The AC breaker panel is the point at which all of a home’s electrical wiring meets with the provider of the electricity, whether that’s the grid or a solar-electric system. This wall-mounted panel or box is usually installed in a utility room, basement, garage, or on the exterior of the building. It contains a number of labeled circuit breakers that route electricity to the various rooms throughout a house. These breakers allow electricity to be disconnected for servicing, and also protect the building’s wiring against electrical fires.
Just like the electrical circuits in your home or office, an inverter’s electrical output needs to be routed through an AC circuit breaker. This breaker is usually mounted inside the building’s mains panel, which enables the inverter to be disconnected from either the grid or from electrical loads if servicing is necessary, and also safeguards the circuit’s electrical wiring.
Additionally, utilities usually require an AC disconnect between the inverter and the grid that is for their use. These are usually located near the utility KWH meter.
AKA: KWH meter, utility meter
Most homes with a grid-tied solar-electric system will have AC electricity both coming from and going to the electric utility grid. A bidirectional KWH meter can simultaneously keep track of how much electricity flows in each of the two directions—just the information you need to monitor how much electricity you’re using and how much your solar-electric system is producing. The utility company often provides Intertied-capable meters at no cost.
AKA: gas guzzler
Off-grid solar-electric systems can be sized to provide electricity during cloudy periods when the sun doesn’t shine. But sizing a system to cover a worst-case scenario, like several cloudy weeks during the winter, can result in a very large, expensive system that will rarely get used to its capacity. To spare your pocketbook, size the system moderately, but include a backup generator to get through those occasional sunless stretches.
Engine generators can be fueled with bio-diesel, petroleum diesel, gasoline, or propane, depending on the design. These generators produce AC electricity that a battery charger (either standalone or incorporated into an inverter) converts to DC energy, which is stored in batteries. Like most internal combustion engines, generators tend to be loud and stinky, but a well designed solar-electric system will require running them only 50 to 200 hours a year.