What Else Does a House Need Besides the Solar Panels?
Summary
Quite a bit. Panels produce direct current, so a home system needs an inverter to turn it into the alternating current your wiring uses, plus a mounting structure that can hold the array for decades. If you want power during a blackout, add a battery and an inverter configured to run without the grid, because a standard grid-tied system shuts itself off when utility power goes out.
Cells, modules, and arrays
A single photovoltaic cell is small. The Department of Energy puts a typical cell at about 1 or 2 watts. Cells are wired in chains to form modules (the panels you see on a roof), and several modules connected together make an array.
The inverter and the racking
Household circuits run on AC, and panels make DC, so the inverter does the conversion. DOE expects an inverter to need replacing at least once during a PV array's 25-year lifetime.
The mounting structure has to survive wind, rain, hail, and corrosion for decades. According to DOE, rack mounting is the most common method today.
Why sunshine won't keep the lights on in an outage
Residential solar is built to depend on the grid. For safety, DOE explains, the systems are designed to switch off when grid power cuts out, so panels alone can't carry a house through an outage. DOE names two things a system needs to produce power on its own: a properly configured inverter and a storage system. Some solar-plus-battery homes detect the loss of grid power and switch to an "islanded" mode automatically.
Sources
- U.S. Department of Energy — Solar Photovoltaic Technology Basics
- U.S. Department of Energy — Solar Photovoltaic System Design Basics
- U.S. Department of Energy — Solar and Resilience Basics
We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.