Solar Energy Glossary

Array – An array is a collection of solar panels that are wired together to form a system.

Degradation – Term used to describe the decline in output that all solar panels experience over time.

Efficiency – As it refers to solar energy, efficiency refers to the percentage of sunlight captured by your panels and converted into energy. High efficiency solar panels are able to convert more power over time than lower-efficiency panels, so buying quality panels will provide a higher return on investment.

Ground-mount solar system – Rather than installing solar panels on a rooftop, they may be installed on the ground if there is sufficient open space and good sun exposure.

Interconnection agreement – A contract between the homeowner and the local utility allowing the homeowner to connect their solar power system to the electric grid. In some areas, this enables the homeowner to receive a credit on their electricity bill from the utility for any surplus electricity their solar power system generates. (See also net metering.)

Micro-inverter – The introduction of micro-inverters is one of the biggest technology shifts in the photovoltaic (PV) industry. Placed on the back of each solar panel, a micro-inverter optimizes energy production for each individual solar panel, not just for an entire solar system, as central inverters do. This enables every solar panel to perform at its maximum potential. It means one underperforming solar panel won’t drag down the performance of entire solar array, as opposed to central inverters that optimize for the weakest link. (See also photovoltaic.)

Net metering – When a grid-tied solar system produces more energy than is needed, the excess power is sent to the electrical grid to be redistributed where it’s needed. This is called “back feeding” the grid. At night, the grid will provide conventionally created power for the solar customer’s use. A net meter records the energy sent compared to the energy received from the grid and credits or charges the user according to local rates and rules. Forty-four states currently offer net metering or some variation of it.

Off-grid – "Off-grid" refers to not being connected to the electrical grid, but it can also include other utilities like sewer, water, and gas. Solar panels coupled with backup battery systems are one of the most popular ways of supplying energy to an off-grid property.

Photovoltaic (PV) – PV technologies convert sunlight to electricity through a naturally occurring process in certain types of material, which are called semiconductors. When photons (energy particles) from the sun hit semiconducting materials such as silicon, electrons are knocked free from their atoms. If conductors are attached to the positive and negative sides of a solar cell, it forms an electrical circuit. When electrons flow through such a circuit, they generate electricity, powering electrical devices or sending electricity to the grid.

Solar battery – Battery systems allow you to store the excess energy your solar panels produce so that you can use it at night or so that you have backup power in the event of an outage. Your battery may also be equipped to sell the excess energy back to the grid.

Solar carports – Solar panel arrays that are raised above parking lots to provide both shade and energy production.

Solar monitoring – Specialized software used to track and manage energy generation and usage, billing, carbon offsets and more; can be accessed via a mobile device, home computer or a remote operations center.

Solar thermal – The process of concentrating sunlight to create high temperatures that are needed to heat fluids, like water (solar hot water) or to vaporize fluid to drive a turbine for electric power generation.

Tracker – Mounting hardware used in power plant installations enabling solar panels to move and follow the sun throughout the day, increasing solar electricity production.

Zero net energy – Zero net energy (ZNE), also referred to as net zero energy, identifies homes or buildings that generate as much energy as they consume, usually via a combination of green building techniques that include a solar energy system.