Many states have metering policies which allow your electric company to credit your account (or pay) for excess solar electricity you produce. When the utility pays you at the same rate for your excess as you pay for electricity used, that is called net metering.
You have the option of including a battery bank and possibly a generator. Without a battery bank or generator backup for your grid-tied system, when a blackout occurs, your household will be in the dark, too. Many homeowners choose to install a grid-intertied system with battery backup in order to keep some or all appliances running even when utility power outages occur.
Incorporating batteries into the system requires more components, is more expensive, and lowers the system's overall efficiency. But for many homeowners who regularly experience utility outages or who have critical electrical appliances, having a backup energy source is priceless.
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Components of Grid-Tied Solar System with No Battery Backup |
A grid-tied system without battery backup ILLUSTRATED BELOW is the most cost effective and the simplest to install. |
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| Components of Grid-Tied Solar System WITH Battery Backup |
A grid-tied solar system with battery backup ILLUSTRATED BELOW will provide electricity even during utility outages. . |
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| Description of Components Solar electric panels—a.k.a solar modules, photovoltaic (PV) panels Pointed towards the sun, solar panels capture the energy in sunlight and convert it directly to DC electricity. There are three general families of solar panels on the market today—single crystal silicon, polycrystalline silicon, and thin film. PV modules are very durable and, because there are no moving parts, long-lasting. Most carry 25 year warranties. Solar panels are assigned a rating in watts based on the maximum power they can produce under ideal sun and temperature conditions per hour. You can use the rated output to help determine how many panels you need. Multiple modules mounted together are called an array. Array Mounting Rack—a.k.a mount, racks, trackers Mounting racks provide a secure platform to keep your panels fixed in place and oriented correctly. Panels can be mounted on your roof, atop a steel pole set in concrete, or at ground level. The type of rack you choose will vary considerably depending on your budget, climate, building codes, and personal preferences. In areas where it snows a lot, you may want to be able to sweep the snow off periodically. Array Combiner/DC Disconnect The DC disconnect is used to safely interrupt the flow of electricity from the array of solar panels. It is an essential component when system maintenance or troubleshooting is necessary. The disconnect enclosure houses an electrical switch rated for use in DC circuits. It also may integrate either circuit breakers or fuses, to combine the electricity of multiple sub arrays of solar panels. The Charge Controller built into a grid-tie inverter uses maximum power point tracking (MPPT) to optimize the array's output, increasing the energy it produces. The controller operates the array at its maximum efficiency and feeds the electricity into the inverter. Battery Bank Grid-intertied systems can include battery banks to provide emergency backup power during blackouts, particulary important if you have critical electric loads which must be operated at all times. In areas susceptible to hurricane or weather-related outages, it is great to have a small bank to support radios and communication equipment during outages. System Status Meter ...are included in most grid-tie inverters. Some offer remote meters with data logging to personal computers. System meters measure and display several different aspects of your solar system's performance—how much electricity your solar panels are producing or have produced, and how much electricity is in use. Operating your solar electric system without metering is like running your car without any gauges. Main DC Disconnect This disconnects your solar array(s) from the inverter. Poletop arrays can attract lightning. You may way to flip the main disconnect during thunderstorms. Inverter Inverters transform the solar-produced DC electricity into the alternating current (AC) electricity commonly used in most homes for powering lights and appliances. Grid-tied inverters synchronize the electricity they produce with the grid's "utility-grade" AC electricity, allowing the system to feed solar-made electricity to your home and the utility grid. Most grid-tie inverters are designed to operate without batteries, but battery-based models are also available. All grid-intertie inverters can be installed outdoors (ideally, in the shade). Lockable Inverter AC Disconnect. This disconnects your solar slectric system from your home and from the grid. Utilities usually require an AC disconnect between the inverter and the grid for their own use. These are usually located near the utility electric (KWH) meter. Bidirectional KWH Meter, a.k.a. your electric meter. Most homes with a grid-tied system will have AC electricity both coming from and going to the electic utility grid. A bidirectional KWH meter can simultaneously keep track of how much electricity flows in each of these two directions—just the information you need to monitor how much electricity you are using AND how much your solar electric system is producing. The utility company will probably supply this meter, but you may have to pay for it. |
