Converting Sunlight into Electricity
Light striking a silicon semiconductor causes electrons to flow, creating electricity. Solar power generating systems take advantage of this property to convert sunlight directly into electrical energy.
Solar panels (also called “solar modules“) produce direct current (DC), which goes through a power inverter to become alternating current (AC) — electricity that we can use in the home or office, like that supplied by a utility power company.
There are two types of solar power generating systems: grid-connected systems, which are connected to the commercial power infrastructure; and stand-alone systems, which feed electricity to a facility for immediate use, or to a battery for storage.
Grid-connected systems are used for homes, public facilities such as schools and hospitals, and commercial facilities such as offices and shopping centers. Electricity generated during the daytime can be used right away, and in some cases surplus electricity can be sold to the utility power company. If the system doesn’t generate enough electricity, or generates none at all (for example, on a cloudy or rainy day, or at night) electricity is purchased from the utility power company. Power production levels and surplus selling can be checked in real time on a monitor, an effective way to gauge daily energy consumption.
Stand-alone systems are used in a variety of applications, including emergency power supply and remote power where traditional infrastructure is unavailable.
When sunlight hits the semiconductor, an electron springs up and is attracted to the n-type semiconductor. This causes more negative electrons in the n-type semiconductor and more positive electrons in the p-type, thus generating a flow of electricity in a process known as the “photovoltaic effect.“
Related Web Sites