How solar panels make electricity
Photovoltaic (PV) cells turn light directly into electricity. The cells have no moving parts, while the illustrated tracker structures turn the modules to follow the Sun. Inverters connect their output to the grid.
Drag to rotate · pinch to zoom · focus the model for arrow-key rotation, +/− zoom and Home reset.
Single-axis photovoltaic array. Modules show a half-cell pattern, underside junction boxes and string leads; electricity flows through separate DC and AC equipment. Motion is slowed for inspection. Coloured overlays reveal flow through enclosed equipment; gold pulses show net electrical energy transfer, not individual electrons.
How it works
- Sunlight
- Semiconductor cells
- DC collection
- Inverter produces AC
- Transformer and grid
A photovoltaic solar plant converts light into electricity inside semiconductor cells. Absorbed light gives charge carriers energy; the cell’s internal electric field separates charge so an external circuit can carry current. Metal contacts collect this output. Cells connect into protected modules, and modules connect into an array. The familiar panel is therefore an electrical generator, rather than a device that boils water. Its usable output depends on the light reaching the cells and their operating conditions.
Modules supply direct current, or DC. An inverter uses controlled semiconductor switches and filtering to deliver alternating current, or AC, suitable for the connected network. Electrical protection, cables and transformation complete the route to the grid. The illustrated tracker changes the panels’ orientation during the day; fixed arrays perform the same photovoltaic conversion without that movement. Solar generation and storage are separate functions: delivering electricity after sunlight has ended requires stored energy or another source of generation.
Inside the engineering
Follow the machinery, the working fluids and the electrical connection.
Mechanical
Steel posts support a torque tube and module rails. The tracker turns the row about one axis to change its orientation to the Sun; module frames and foundations resist wind loads.
Thermal & chemical
Light absorbed in semiconductor cells produces charge carriers; the cell junction separates them. This is photovoltaic conversion, without a steam cycle. Temperature affects cell voltage and performance.
Electrical
Cells and modules form DC strings. Protected DC collection feeds the inverter, which controls conversion to AC. AC switchgear and a transformer connect the array to the grid; a transformer alone cannot convert DC into AC.
Main types and variations
The model illustrates tracking photovoltaic panels. Mounting, cell material and inverter arrangement are independent design choices that can be combined. Concentrating solar-thermal power uses a different conversion process entirely.
Fixed-tilt photovoltaics
Modules remain at a chosen angle and orientation on a permanent mounting structure. The structure must support the array and withstand environmental loads. The Sun’s angle changes across the day and seasons, while the cells continue producing DC whenever sufficient sunlight reaches them; no tracking drive is required.
What changes in practice
This provides a straightforward mounting arrangement for roofs and ground arrays. Orientation and shading still matter, even though there are no tracking mechanisms to operate.
Single-axis and dual-axis tracking
A tracking structure rotates modules to change their orientation to the Sun. Single-axis tracking, as illustrated, turns an array around one axis; dual-axis tracking adjusts around two. The panels still generate through the photovoltaic effect: the mechanism changes how sunlight reaches them, rather than changing the cell’s conversion process.
What changes in practice
Tracking can increase captured sunlight, but adds moving structures and controls. The choice depends on site conditions, mounting constraints and the value of the additional energy.
Crystalline-silicon and thin-film cells
Crystalline-silicon cells use silicon wafers, whereas thin-film technologies deposit semiconductor layers onto a supporting surface. Cadmium telluride and copper indium gallium diselenide are examples of thin-film materials. Both create electrical charge from absorbed light; different materials and structures absorb and convert the solar spectrum differently.
What changes in practice
Cell chemistry affects manufacturing and module performance. Material choice is independent of whether panels are fixed or tracked and of the inverter architecture downstream.
String and central inverters
A string inverter converts DC from connected groups of modules into AC. A central-inverter arrangement collects output from a larger part of an array before conversion. Both use power electronics rather than a rotating generator; their distinction is how the solar field is divided and electrically collected.
What changes in practice
Grouping determines which panels share conversion equipment. Shading, maintenance and a converter outage can affect different portions of the plant depending on the electrical layout.
Microinverters and module-level control
A microinverter converts output at an individual panel instead of feeding a common DC string inverter. Panels can therefore operate more independently when their conditions differ. A DC optimiser is a different device: it controls a module’s DC output but still needs an inverter elsewhere to produce AC.
What changes in practice
Module-level equipment can help with uneven shading or roof orientations. It also distributes more electronics across the array, changing installation, monitoring and maintenance considerations.
Concentrating solar-thermal power (CSP)
Mirrors concentrate sunlight onto a receiver, producing high-temperature heat. A working-fluid system then supplies an engine or turbine-generator. Tower systems use mirrors aimed at an elevated receiver; linear systems focus along receiver tubes. This is a heat-engine power plant, distinct from the photovoltaic panels shown in the model.
What changes in practice
CSP can incorporate thermal storage before electricity generation. Its receivers, heat-transfer circuits and power block make it mechanically and thermally different from a PV-and-inverter plant.
Worth knowing
- Solar plants produce nothing at night, so their average output is well below rated capacity.
- Panel makers and inverter suppliers are rarely published in open plant registers.
- Rooftop systems work the same way at a much smaller scale.
See real examples
The atlas includes 19,160 solar records worldwide.
Show on the mapRelated answers
Textbook references
The science on this page follows these standard engineering textbooks. See the full bibliography.
- Handbook of Photovoltaic Science and EngineeringSemiconductor physics of solar cells, module technologies and system design.
- Renewable and Efficient Electric Power SystemsPV system sizing, inverters and the difference between DC and AC ratings.
Sources
- EIA: Photovoltaics and electricity ↗
- US DOE: Photovoltaic cells, modules and systems ↗
- SMA: Utility-scale inverter, transformer and switchgear arrangement ↗
Cutaways reveal enclosed equipment. Layouts, dimensions, materials and animation speeds are illustrative; this is an educational model, not a plant design or a thermodynamic simulation.