Solar science, simply explained
How Solar Works
From photon to appliance in four steps — plus net metering, batteries, and how we size your system.
Energy flow diagram
Step by step
Photovoltaic panels absorb sunlight
Each solar panel contains photovoltaic (PV) cells — typically monocrystalline silicon. When photons from sunlight strike the cells, they knock electrons loose, creating a flow of direct current (DC) electricity. Modern panels convert 20–23% of sunlight to electricity.
Panels are wired together in strings. Series wiring increases voltage; parallel wiring increases current. Your HELIO designer optimises the string configuration for your roof layout, shading pattern, and local irradiance data.
Inverter converts DC to AC
Your home runs on alternating current (AC). A solar inverter converts the DC from your panels into grid-compatible 240V AC. We install string inverters for straightforward rooftops, or microinverters (one per panel) for complex roofs with shade.
Modern inverters have built-in Wi-Fi monitoring and a 97%+ conversion efficiency. They also handle grid-tie safety, disconnecting automatically during a grid outage so line-workers stay safe.
Electricity flows to your home first
Solar power flows directly to your loads — appliances, lights, HVAC, EV charger — before touching the grid or battery. During peak sun hours most homes consume less than they generate, so the balance goes somewhere useful.
Your utility meter records both import and export. Under net metering, the kWh you export earns you a credit applied to the kWh you draw back at night — typically at the same rate.
Surplus charges your battery or goes to the grid
With a battery (e.g., a 13.5 kWh lithium-iron phosphate unit), excess daytime generation charges the battery first. The battery discharges in the evening, extending your solar self-consumption to 24 hours.
Without a battery, surplus goes back to the utility grid, earning net-metering credits. Many Oregon and Washington utilities offer full retail credit — meaning your meter genuinely runs backwards.
You draw from the grid when needed
Cloudy days, winter months, and overnight usage pull from the grid, but your credits offset most of this cost. Most HELIO systems are sized so annual generation equals or exceeds annual consumption — a net-zero electricity bill.
System sizing accounts for your 12-month usage history, future changes (EV, heat pump), and local solar resource data from NREL's PVWatts database.
Net metering
Your meter runs backwards when you over-generate
Net metering is the billing mechanism that makes solar financially viable. When your panels generate more electricity than you consume, the surplus flows to the grid and your utility credits your account at the retail electricity rate.
- Oregon and Washington both mandate net metering at retail rates for systems under 25 kW residential / 2 MW commercial.
- Your utility installs a bi-directional meter that measures both export and import separately.
- Monthly credits roll forward. Any annual surplus is settled at the avoided-cost rate (typically 60–80% of retail).
- Time-of-use (TOU) rate plans can be advantageous with battery storage — charge cheap, export at peak.
Battery storage
Independence from the grid — day and night
Battery storage (we spec lithium-iron phosphate — LFP — chemistry for safety and cycle life) lets you store excess midday generation for evening use. Benefits:
- Outage protection — power critical loads for 8–24+ hours
- Maximise self-consumption when net-metering rates are below retail
- Peak-demand shaving for commercial customers on demand tariffs
- Pair with EV charging for a fully solar-powered household
Ready to see your system?
Run our interactive savings calculator to see a projected system size, annual savings, and payback period for your home.