How it Works

Solar electricity works on the photoelectric effect - photons striking the surface of a specially coated slice of silicon (a photovoltaic cell) force electrons to break away from their orbits around certain atoms inside that silicon. Those free electrons "wander" long that surface until they are captured by small wires embedded in the silicon, and shuttled down that wiring from cell to cell, and thus out the positive end of the module all of the cells are wired together to form.

Wiring many modules together in series creates a large array of modules with a combined voltage (very high - 300 to 500+ volts DC) that is run down specially rated wire to the first of two disconnect switches (the DC disconnect switch) along with the ground wire from the frames of all the modules. That DC disconnect switch allows the entire array to be safely de-energized in the event that work needs to be done on that array or the surrounding area.

Wiring continues from the DC disconnect switch to the DC-to-AC inverter, a special piece of equipment that converts very high DC voltage power to lower voltage (120 to 240 Volts) AC power, and synchronizes the output AC power in line with the power being produced and distributed over the utility's electric grid. Ground wiring is connected from the frame ground of the array to the service ground of the grid at this point.

Normal wiring continues out the AC side of the inverter to the second of the disconnect switches - the AC disconnect switch. This AC switch is mandated by PG&E to protect their field personnel in the event that their grid loses power, and needs to be worked on. Without that AC disconnect switch, the solar electricity "power plant" on your property would still be "live" and putting power onto the grid, so for the safety of the lineperson, your array is de-energized by use of the AC disconnect switch.

The normal wiring continues out the AC disconnect switch to your existing electric meter, where on days when your system is producing more electricity than you are using at that moment, your meter will actually spin backwards! The electricity produced by your system is actually sent into the electric grid and when your meter is spinning backwards, creates an electricity "credit" on your account that you can draw upon during the evening hours or cloudy days. If your site evaluation shows us that conditions are optimal, and your budget can handle the one-time investment, you could produce 100% of your electric needs from the sun and have an annual PG&E bill of zero!