Power Purchase Agreement (PPA)

A Power Purchase Agreement (PPA) is an agreement between a homeowner/building owner and Solar City, where Solar City covers the full cost of installing and maintaining a solar system. In return, the host customer agrees to buy the power produced by the system. This allows building owners to pay as they go, rather than in one large upfront payment.

On/Off Grid System

A solar energy system that is interconnected with the utility grid is said to be an on-grid or grid-tied system, while a system with battery storage is not interconnected and is described as an off-grid system.

What is Inverter

A device that converts DC power captured by the photovoltaic cells on solar panels into AC power that can be used to power your home or business. This device is an integral part of a solar system. Large solar systems may have more than one inverter.

What are Greenhouse Gases

Gaseous components in the atmosphere that contribute to a gradual warming of the planet. The most prevalent of these gases is carbon dioxide, which is released in large quantities when fossil fuels are burned. Nothing is burned to convert sunlight into power. Since solar energy does not have any gaseous by-products, it is considered "clean."

What is DC Power

An electrical current whose magnitude and direction stay constant. The photovoltaic cells on solar panels capture energy from sunlight in the form of DC. In order to power your home or business, this current must be converted to AC by an inverter.

What is AC Power

An electrical current whose magnitude and direction varies continuously and sinusoidally. AC is the form in which electricity is delivered to businesses and residences. It can be thought of as "standard" electrical power.

What is a a Battery ?

Two or more electrochemical cells enclosed in a container and electrically interconnected in an appropriate series/parallel arrangement to provide the required operating voltage and current levels. Under common usage, the term battery also applies to a single cell if it constitutes the entire electrochemical storage system.