Frequently Asked Questions
1.) How Does Solar Work?
When the sun shines on solar panels, the panels produce DC (direct current) electricity. By running this DC power through a machine called an Inverter, the DC power from the panels is inverted to usable AC (alternating current) electricity which is similar to what powers your home.
There are different types of solar power systems. Most people envision an "off-grid" system when they think of Solar (i.e. solar panels that charge batteries to power your house year round without the need to draw power from a utility service). However, most Solar Installations are Solar Photovoltaic (PV) systems that work in conjunction with your utility service. The system is connected directly to, and works in sync with, the grid, bypassing your home's electrical system altogether.
2.) How Much Solar Do I Need?
Solar system size is measured in kilowatts (kW). Sizing a system depends on several factors, but location of the installation and energy usage of the property will typically be the most significant.
Location of the property of a solar installation determines what utility company you interface with. Each utility has its own way of compensating you for the energy you produce. Your utilities' compensation method can make it sensible to either increase or decrease the size of a system. Some utilities offer a power purchase agreement in which they will pay you for the energy you supply to the grid via your Solar PV System. Utilities in TVA territory will actually pay you MORE for each kilowatt-hour of energy you generate than they charge you for the energy you use, allowing you to recover the cost of your system faster.
Energy Usage of the property could limit the size system you are allowed to install. For example, TVA allows installations of 10 kW size solar systems regardless of energy usage history. A 10 kW solar system will produce roughly the amount of energy that a typical 2-3 bedroom house uses. A larger home or home with larger than average energy needs will often require more than a 10 kW system to offset its energy use. When sizing a system, using a one year history of utility bills is the best way to determine your property's energy usage.
3.) How much space does a Solar System take?
A rule of thumb is around 80 sq. ft. per 1 kW for a standard roof mount.
4.) How Much does Solar Cost?
The cost of Solar PV can vary significantly depending on the installation conditions and optional features such as solar monitoring. With incentives, a Solar PV System can have a payback in under 7 years for business installations and under 12 years for residential installations.
5.) What Incentives are Available?
The federal government offers a 30% tax credit that is claimable for both residential and commercial installations. Commercial installations can claim MACRS 5 year depreciation with a bonus 50% claimable in the first year.
In addition to the federal incentives, individual state and local incentives are available. Each state and power company adopts different strategies to boost solar installations in their area. Southern Solar is licensed to install solar in Alabama, Louisiana,Tennessee and Texas. See the links below for specfic incentives for your local area.
6.) What happens during power outages?
Solar PV Systems are designed to work in sync with the grid. Meaning, if the grid experiences a power outage, the Solar PV System's inverter will detect it and automatically shut off. This is for the utility lineman's safety. Beacuse of this, a grid-tied Solar PV System will not be able to provide power to a house during such outages. If off-grid power is desired, an off-grid or battery back-up system is required resulting in higher costs and lower efficiency.
7.) What about Hail and Wind?
Solar PV modules are rated for 1 1/4" hail at 50 mph. Any hail smaller than that size that damages a module will be under the standard warranties offered by the manufacturer. Wind is as much a threat to solar as any other structure. Southern Solar designs and installs to all federal and local building codes.
8.) What about Batteries and off-grid solar?
Batteries are only required for off grid solar systems or in systems where back up power storage is needed. These sytems are less common than grid-tied systems because they cost more to install, are less efficient, and require more maintenance.
9.) Must I consistently use a lot of power for a Solar PV System to be cost effective?
Not usually. It depends on how the utility you tie into structures system tie-ins and power purchase agreements (PPA). Solar PV is equally useful for everyone (regardless of how consistently you use power) when installed under the right PPA. TVA's Green Power Providers program is one of the best for Solar PV. Through their power purchase contract, they will pay you for ALL the energy your system generates for 20 years regardless of your power consumption consistency. Participants will be paid the applicable retail rate PLUS a generation premium rate for the first 10 years. This means, you actually collect more than you pay for each kilkowatt-hour(kWh) your system generates. For years 11 through 20, participants are paid the applicable retail rate only. Contract extensions may also be available for an additional 10 years paid at retail prices.
First 10 Years (retail rate + TVA premium)
Years 11-20 (retail rate)
Years 21-30 (contract extension likely available at retail rate)
10.) Are Solar Hot Water systems more cost-effective than Solar PV?
This is generally true; however, because of the TVA premium rate, it makes more sense to install Solar PV system to offset the energy use of a standard water heater instead of a solar hot water system. Because of this, TVA customers are better off installing a Solar PV System. Customers outside of the TVA area will more than likely find Solar Hot Water more cost-effective than Solar PV.
11.) Will Solar PV be an optimal solution for me?
There are some important details to consider when deciding whether to install solar. Not all sites are conducive for a Solar PV System.
Shading – Shading from trees, buildings, and other indispensable sources can be problematic if excessive. Most installs will have a little shading that is not generally an issue. We perform site visits for all of our projects and will measure the shading of every site to ensure proper location of install.
Roof Space/Condition – Small roof area should not be a determining factor for installing solar panels. Panels would be just as effective installed on un-shaded ground as they would on a roof. In fact, if a roof is aging or due for replacement in a few years, it may be wise to install a ground-mounted solar array to save the money and trouble of removing and reinstallation of the solar panels.