Solar Energy
An animated brief explanation of Solar energy, collecting, using, and storage
Interactive diagram of the solar energy cycle: sunlight hits panels producing DC electricity, an inverter converts it to AC for home use, surplus charges a battery pack during the day, and the battery discharges to power the home at night.
Toggle between day and night to see the flow reverse
Toggle the switch above to flip between day and night — you'll see the panel glow fade, the flow lines reverse direction on the battery line, and the charge level drop as it switches from charging to discharging.
Here's how the six stages connect:
1.
Sunlight → panels — photons hit the photovoltaic cells and knock electrons loose, producing DC (direct current) electricity.
Sunlight → panels — photons hit the photovoltaic cells and knock electrons loose, producing DC (direct current) electricity.
2.
Panels → inverter — that raw DC power travels down to the inverter, which is the translator of the system.
3.
Inverter → AC — the inverter converts DC into AC (alternating current), the form your home's outlets and appliances actually use.
Inverter → AC — the inverter converts DC into AC (alternating current), the form your home's outlets and appliances actually use.
4.
Usage — AC power flows straight to the house for immediate use — lights, appliances, everything running in real time.
Usage — AC power flows straight to the house for immediate use — lights, appliances, everything running in real time.
5.
Storage — whatever the house isn't using gets routed into the battery pack, charging it for later.
Storage — whatever the house isn't using gets routed into the battery pack, charging it for later.
6.
Night discharge — once the sun goes down and the panels go idle, the battery reverses direction and feeds power back through the inverter to keep the house running until sunrise.
Night discharge — once the sun goes down and the panels go idle, the battery reverses direction and feeds power back through the inverter to keep the house running until sunrise.
Diagram of an inverter: steady DC power enters a switching bridge, where two pairs of switches alternate rapidly, producing a choppy square wave that gets smoothed into a clean AC sine wave.
Cross section of a solar cell: sunlight strikes the junction between an n-type and p-type silicon layer, freeing electrons that flow out through metal contacts, around an external circuit through a load, and back into the cell as direct current.
Once AC power leaves the inverter, it flows through your home's main electrical panel — the same breaker box that grid power would use — and from there the system follows a priority order:
1.
Your appliances get first claim. Whatever your home is drawing right now — lights, fridge, HVAC, whatever's running — gets served directly from solar production. This happens instantly and automatically; there's no delay or switching involved.
Your appliances get first claim. Whatever your home is drawing right now — lights, fridge, HVAC, whatever's running — gets served directly from solar production. This happens instantly and automatically; there's no delay or switching involved.
2.
Leftover power charges the battery. If your panels are producing more than the house is using at that moment (common around midday), the surplus routes to the battery pack until it's full.
Leftover power charges the battery. If your panels are producing more than the house is using at that moment (common around midday), the surplus routes to the battery pack until it's full.
3.
Any power beyond that exports to the grid. Once the battery's topped off and the house is satisfied, extra production gets pushed out onto the utility grid. Depending on your utility and country, this either earns you a credit (net metering), gets bought at a wholesale rate, or in some setups isn't compensated at all — worth checking your specific utility's policy.
Any power beyond that exports to the grid. Once the battery's topped off and the house is satisfied, extra production gets pushed out onto the utility grid. Depending on your utility and country, this either earns you a credit (net metering), gets bought at a wholesale rate, or in some setups isn't compensated at all — worth checking your specific utility's policy.
4.
When solar isn't enough, the grid fills in. On a cloudy stretch, or the moment demand spikes past what your panels are making (say, the AC and oven both kick on at once), the shortfall is drawn from the grid — or from the battery first, if you have one and it's charged, before the grid ever gets tapped.
When solar isn't enough, the grid fills in. On a cloudy stretch, or the moment demand spikes past what your panels are making (say, the AC and oven both kick on at once), the shortfall is drawn from the grid — or from the battery first, if you have one and it's charged, before the grid ever gets tapped.
A smart meter at the utility connection point tracks all of this — how much you're importing versus exporting — which is what your utility bill (or credit) is based on.
One nuance: the exact priority order between "charge the battery" and "export to the grid" is actually configurable on most modern systems. Some people set theirs to prioritize battery charging for backup security; others prioritize export if their utility pays well for it.
One nuance: the exact priority order between "charge the battery" and "export to the grid" is actually configurable on most modern systems. Some people set theirs to prioritize battery charging for backup security; others prioritize export if their utility pays well for it.
Diagram of a lithium-ion battery cell during charge and discharge. Toggle between charging, where lithium ions move from the cathode to the anode through the electrolyte while an external charger drives the current, and discharging, where ions move back to the cathode, releasing power to a load.