Joey Casebier, left, and Brice Goin of Sustainable Future install photovoltaic panels on the roof of the BlueCross BlueShield Gateway Building in downtown Chattanooga on Thursday. The installation will be the largest solar energy project yet in downtown Chattanooga.

Spurred by grants from the Tennessee Solar Institute, 13 Hamilton County businesses have installed rooftop solar panels for energy generation in the past year. The biggest projects, ranked by investment, include:

1. TOP FLIGHT INC., $1.04 million system capable of generating 197.4 kilowatts, aided by $242,400 grant from the solar institute

2. 350 CORPORATE PLACE LLC, $1.04 million system capable of generating 196.56 kilowatts, aided by $241,560 in solar institute grants

3. 650 WAUHATCHIE PIKE LLC, $1.04 million system capable of generating 196.56 kilowatts, aided by $241,560 in solar institute grants

4. BLUECROSS BLUESHIELD OF TENNESSEE, $915,000 project at its Gateway Building capable of generating 198.24 kilowatts, aided by $243,240 in solar institute grants

5. NORTHGATE PARTS INC., an $871,093 system capable of generating 130.9 kilowatts, aided by $175,900 in solar institute grants

Source: Tennessee Solar Institute