Solar PV systems create clean, renewable energy. These systems can run independently or be connected to the utility grid.
Most domestic solar PV systems are grid-tied. When your system over-produces during the day it sends electricity back to the power grid.During the night or when your system isn’t producing power it will seamlessly draw electricity from the grid. This is known as net metering.Photovoltaic CellsPhotovoltaic cells convert sunlight, the most abundant energy source on Earth, into electricity. Sunlight is absorbed by semiconductor material in the cell, where it causes electrons to dislodge from their atoms and move toward the cell’s treated front surface. This imbalance of electrons creates a current of DC electricity when the cell is connected to an external circuit.Solar cells are made of thin layers of semiconducting material, primarily silicon. They are grouped together into modules or “solar panels,” and then housed in a protective encapsulation to withstand environmental factors such as rain, hail, snow and ice.Solar panel efficiency is determined by the ratio of electrical power generated to the amount of sunlight that strikes the solar module. Efficiency can be improved by using cadmium telluride (CdTe) or cadmium indium gallium selenide (CIGS) solar cells, which have higher efficiency ratings than traditional silicon solar cells. These cell technologies use multiple layers of semiconductor materials to absorb more light and reach record efficiencies.InvertersAn inverter converts direct current electricity, which solar panels produce, into alternating current that the grid can use. It does this by rapidly switching the direction of electrical flow. This creates a waveform that is clean and repeatable, which the grid can accept without damaging equipment.Inverters also provide additional grid services, like balancing generation and demand. They can send signals to solar systems to change their power output when the grid needs more or less of it.In addition to their grid-tie functions, some inverters can connect directly to battery storage, making them a solar-plus-storage system. These all-in-one units can be either a grid-tie or off-grid (standalone) system and may include features such as maximum power point tracking and anti-islanding protection.Solar PanelsSolar panels are one of the key components that form a solar power system. They contain individual photovoltaic cells that are grouped together to create a larger solar panel. When paired with an inverter, solar panels convert direct current into alternating current electricity.Solar power is a renewable energy source that emits no greenhouse gasses and provides clean, cost-effective electricity to homes and businesses. It is also a reliable energy resource that will last for decades.A standard solar panel is made of a protective backsheet, silicon wafers (which contain the photovoltaic material) and metal connectors. They are then arranged into a solar module with the cell’s conductive layer on the bottom and a glass sheet on top. Blocking and bypass diodes may be incorporated into the solar module or used externally to deal with partial array shading which would otherwise severely limit power output. The modules are then framed in metal frames that latch onto mounting clamps on your roof.BatteriesBatteries store the surplus energy generated by solar panels to power appliances at night or on cloudy days. They use electrochemical cells – like Volta’s pile of zinc and silver – with different types of electrodes separated by an electrolyte to produce a flow of electrons that can be used as electricity.A battery bank’s size (measured in kilowatt-hours, kWh) is determined by the energy consumption of your household, including the maximum power output of any appliances you want to run at once. In addition, system efficiencies and temperature coefficients need to be factored in.Some grid-tied solar systems use on-site batteries to help maximize utility bill savings by reducing energy consumption during peak hours when rates are highest. This strategy is especially important in areas with long, dark winters.