HOME ENERGY - REDUCING COSTS AND CARBON
* THE SYSTEM COMPONENTS for a grid-tied solar system
Solar power is cost effective and carbon free. It is a simple system that is easy to install and use, maintenance free and available with a 26% tax credit. Components in the photos below include the solar panels, mounted on a roof or on a ground mount. Brains of the system are in a combiner box about 15” x 15”, located somewhere near the breaker box in the house. A knife cutoff switch and second meter are located outside the house.
All solar generated power is measured by this second meter and sent to the utility. All power for the house is drawn from the utility and measured by the original utility meter. The user pays for or is paid for the difference between these two values. That’s it. Nothing more to do or pay attention to.
All solar generated power is measured by this second meter and sent to the utility. All power for the house is drawn from the utility and measured by the original utility meter. The user pays for or is paid for the difference between these two values. That’s it. Nothing more to do or pay attention to.
MEASURED PERFORMANCE
This 8.4Kw system has been operating for 21 months at an average production of 940 KWh/month. At $0.16/KWh the avoided electric cost is $1800/year for an 11% return on the investment. Carbon reduction is about 12 tons or 24% for a family of three to satisfy the 7% yearly reduction goal for over 4 years. It has also produced 4.1 MWh of unused electricity, enough to power a plug-in hybrid vehicle over 12,000 miles of fuel and carbon free city driving.
SPECIAL NOTE: If the solar power is used to charge a PHEV or BEV it becomes worth $0.36/KWh and the return on investment becomes 25%. More details.
SPECIAL NOTE: If the solar power is used to charge a PHEV or BEV it becomes worth $0.36/KWh and the return on investment becomes 25%. More details.
SOLAR SYSTEM DAILY GENERATION REPORT
A screenshot of results from an app shows 32.6KWh more generation than use.
Backup for a power outage can be supplied by a gasoline powered generator with manual switchover interlock (about $400 for 3500 watts), a natural or propane gas powered generator with automatic switchover (about $7000) or a battery backup with automatic switchover (about $11,000 for one unit). Batteries are limited to short term backup. Some recent solar systems may even provide solar power even when the utility is off, but only during daylight, of course.
Use the website link below to estimate annual solar production for your site. It is probably better than you expect. Estimates from this calculator match the actual generation produced by this example system almost perfectly. If the calculations for a roof mount are not favorable, consider a ground mount. Since power is transmitted from the panels to the breaker box over small gauge wires distance is not an issue.
pvwatts.nrel.gov/pvwatts.php
Backup for a power outage can be supplied by a gasoline powered generator with manual switchover interlock (about $400 for 3500 watts), a natural or propane gas powered generator with automatic switchover (about $7000) or a battery backup with automatic switchover (about $11,000 for one unit). Batteries are limited to short term backup. Some recent solar systems may even provide solar power even when the utility is off, but only during daylight, of course.
Use the website link below to estimate annual solar production for your site. It is probably better than you expect. Estimates from this calculator match the actual generation produced by this example system almost perfectly. If the calculations for a roof mount are not favorable, consider a ground mount. Since power is transmitted from the panels to the breaker box over small gauge wires distance is not an issue.
pvwatts.nrel.gov/pvwatts.php
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