September 24, 2009
Austin Energy to Build Austin’s Largest Solar Roof Top on City Building

The Austin City Council today approved a construction contract that will allow Austin Energy to build the city’s largest solar roof top installation using a new thin film solar product.

One-thousand solar panels will be added to the Austin Water Utility’s Glen Bell Service Center beginning Nov. 1. The 77,000 square foot service center at 3907 South Industrial Drive recently replaced its worn roof with a new membrane roof top that works well with this type of solar panel, which is only a quarter of an inch thick. Each panel will be 18-feet long by 15 and a half inches wide. The entire installation will cover 23,250 square feet of roof space.

When complete, the 136-kW system will have a peak electrical output of 105 kW, with a capacity factor of about 18%. It is expected to reduce peak demand by about 24 kW and save 167,605 kWh annually. That’s enough power to provide electricity to 17 average-sized homes in Austin for an entire year.

The panels are a lightweight thin film that peels and sticks directly onto the roof top, compared to traditional modules that are mounted on racks. The thin film weighs three-quarters of a pound per square foot, compared to 20-25 pounds per square foot for a standard rack-mounted module.

This thin film design benefits customers who are unable to use rack systems due to building height and structural integrity, exposure to high wind loads, or strict requirements related to aesthetics. Thin film technology also performs better in the early mornings and evenings because it can capture sunlight at any angle due to the panels laying flat. The manufacturer offers a 20-year warranty on the product, and the life span of the modules is estimated at 25-30 years.

This latest installation at Glen Bell is part of Austin Energy’s Strategic Plan to install solar panels at highly visible locations such as City buildings, libraries, and schools as a way to create public awareness and educate citizens about the advantages of using solar power. This is the 30th City facility to receive a solar installation. Solar systems have also been installed by Austin Energy at 21 schools.

While this particular installation is a capital improvements project, Austin Energy’s Solar Rebate Program is one of the utility’s most successful programs. As of August, there were 831 residential systems and 75 commercial systems. Total installed solar capacity in Austin is 3.4 MW.