Bruce Saller, ADVANCE CONTRIBUTOR
A new Virginia law allows electric customers to install plug-in (or balcony) solar systems producing up to 1200 watts beginning January 1. A solar system facing South will generate 1.5 kilo-watt hours per year for each system watt. So, a 1200-watt system will produce 1800 kilo-watt hours, or 15 percent of a typical customer’s usage, saving $324 per year.
Plug-in solar systems consist of solar panels, an inverter that converts the panels’ direct current output to alternating current, cabling, and possibly a mounting structure. The inverter has a plug that goes into a standard wall outlet. The solar panels can be installed on a roof, hung from a balcony, installed on a ground structure, or leaned against a wall.
I’ve found a range of solar systems online with panels ranging from 180 watts (46 x 34 inches, 11 pounds) to 590 watts (89.7 x 44.6 inches, 68 pounds). All the systems have two panels. The prices ranged from $465 for a 360-watt system (no installation hardware) to $2300 for an 1180-watt system with ground mount hardware. The larger systems can be shipped with ground, balcony, or roof mounting hardware. The mounting hardware is easy to assemble, and you may be able to do it yourself.
The 380-watt system would save you $97 yearly, so you would recover your costs in 5 years (if you just lean the panels against a wall). The 1180-watt system would save you $318 yearly, taking you 7.5 years to recover your cost (less if you didn’t need the installation hardware).
If you plan to install the system on the ground, consider buying a single-axis tracker mount. They cost several hundred dollars more but increase the solar energy output by up to 25 percent.
The State Corporation Commission has published the system requirements and connection form (Small Portable Solar Generation Device Notification). The inverter needs to have been tested by a nationally recognized testing laboratory and meet electrical standards UL 3700 and UL 1741. You have to complete the form and mail it to your utility. The address for Dominion is:
Dominion Virginia Generator Interconnections
600 E. Canal Street - Floor 11 South
Richmond, Virginia 23219
Dominion has 15 days to reply. If you haven’t heard from them in 15 days, you can plug in your system.
You need to purchase the inverter before completing the form since you need to enter the model and serial numbers. Since it takes about 4 weeks to receive a system, you may want to order one in early November if you want to connect it January 1.
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Bruce Saller is a retired systems engineer with degrees in electrical engineering and computer science.
