Here is a brief introduction to Solar PV, grid tied, ground mount and community solar.
PV technology generates electricity by capturing photons which convert energy into a flow of electrons. PV cells range from 10 to 28% in efficiency, while newer more exotic materials have generated over 45% in the lab – they are not commercially available as of 2015. Most PV cells generate the highest amount of electricity when 90’ or perpendicular to the sun.
Stand alone – systems rely on batteries to store solar power, for use later at night. Inverters with charge controllers are required to charge the batteries and keep them happy. Batteries add cost to the installation, and require extra maintenance. This kind of system is often user where the cost of bringing in power is prohibitive. Thee systems often employ a backup generator for extended cloudy days. Sometimes a wind generator is added to tne mix depending on location.
Batteryless Grid-tied – systems require no battery and are the most common. They use the electric grid to “store” electricity, for use later when the sun is down. These are less expensive to install because of the simpler inverter and no need for a battery bank or charge controller. The down side is if the grid power goes down, you are also out of power – unless you have a backup generator and critical load center; both add additional cost.
Community solar is a batteryless grid tied system, using larger inverters and many more panels. With community solar power is fed to the grid at one location like any power plant does, and you use that power normally. If you invest in community solar, you will see a credit on your power bill in proportion to the number of panels you have purchased. For more information about community solar see the FAQ section.
Battery backed Grid-tied
This is a hybrid system with batteries that can power all or part of your home, for a period of time, while the solar panels or the grid provide the charge to keep the battery system topped up. In case of a grid outage, this system can switch to battery power. This is the most expensive system type, because of the more complex inverter, and the included or stand alone battery charge controller, and batteries, which usually last 5 – 10 years and then must be replaced.
For a more in depth read please check the PV primer.