Photovoltaic (PV) technology turns sunlight directly into electricity. Here is how that happens, step by step.
The photovoltaic effect
At the heart of photovoltaics is the photovoltaic effect. When light — particularly visible and near-infrared wavelengths — strikes certain materials such as silicon, the energy of the photons can free electrons and set them moving. That movement of charge is electric current.
Silicon cells: the building blocks
Most solar cells are made from silicon, treated with small amounts of other elements to create layers with different electrical properties. The junction between those layers creates an electric field inside the cell. When photons arrive, the freed electrons are swept along by that field, producing direct current (DC).
From cells to modules to arrays
A single cell produces only a small voltage, so many cells are wired together in series and framed behind glass to form a module — the familiar solar panel. Modules are in turn wired together into an array sized for the site. More unshaded area means a larger array and more generation.
Making alternating current with an inverter
Homes and businesses run on alternating current (AC), not the DC that panels produce. The inverter is the device that converts DC into AC by switching the current's direction rapidly to match the grid's rhythm. Modern inverters also monitor the array and provide safety functions.
Connecting to your home
Once converted to AC, electricity flows to your home's electrical panel, where it is used just like grid-supplied power. On sunny days, when generation exceeds consumption, a grid-tied system may export the surplus to the utility grid, subject to the interconnection rules and metering arrangements of your local utility.
For a deeper look at the science, see The Photovoltaic Effect Explained, and for the hardware, visit System Components.