Improvements to technology pique interest

Solar power system on a small ranch house

Solar power panels on a small ranch house. Photo by the National Renewable Energy Laboratory.

As solar power equipment prices continue to decline, more and more people are becoming interested in installing solar power options on their homes and businesses. But many challenges and questions remain about how to implement the technology.

Elizabeth Gall, a solar and sustainable energy specialist with University of Tennessee Extension, says you first have to take stock of your situation before deciding if solar power is an option for you.

“The first step towards implementing any new renewable energy technologies is to make all the conservation and efficiency improvements you can. Doing this first will mean you can install the smallest possible renewable energy system,” said Gall. “After conservation and efficiency measures are in place, an assessment of your building and location are necessary. Some questions to ask yourself are “Do I have a south-facing roof? If not, can I mount panels on the ground so that they face south?”  A southern exposure will allow for the most efficient use of the sun’s energy.

If you are considering a roof-installation, Gall said you should also answer these questions: “Do I have enough roof space and is my roof in good condition? Is my roof unshaded?” Gall said some solar power systems can last between 20 and 30 years, so it is best to start with a new or nearly new roof before installing a roof-based solar power system.

Another consideration, Gall said, is accurately estimating the size of system required. “It is difficult to give an exact estimate on size/capacity needed because that is dependent on many factors such as your family’s overall electricity usage and the amount of power you want to come from the renewable system,” she said.  However, UT Extension can help.  Sizing worksheets for a variety of applications are available on Extension Publications website. Use the search term “solar.”

Solar power systems, as of 2014, cost roughly $1-2 per watt ($4-5 per watt when installation costs are included). A significant savings can be found if you buy the components and install the system yourself, but it is recommended that a certified electrician hook the system up to the transmission grid. Solar panels can be purchased at several tool and equipment suppliers.

Financial incentives for installing solar power include a 30 percent federal tax credit in effect until December 2016.

Gall states, “Energy storage options are evolving, and are a good option in remote areas, but most people choose to connect to the grid in what is called a “grid-tied” or “grid-connected” system.” Many utility providers or distributers, such as the Tennessee Valley Authority (TVA), provide incentive programs for “selling” your excess electricity back to the grid. “This also allows you to have back-up power when the sun is not shining or the panels are not producing enough,” says Gall.

For additional information, contact Extension specialists Elizabeth Gall ( or Tim Prather ( with the UT Department of Biosystems Engineering and Soil Science.  You can also reach them by phone at 865-974-7266.

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the UT Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.



Elizabeth Gall, Department of Biosystems Engineering and Soil Science,

Tim Prather, Department of Biosystems Engineering and Soil Science,