About 40 years ago, Walter Cronkite characterized Chattanooga, TN, as one of the dirtiest cities in America. Since then, officials have worked to transform it into one of the cleanest, and the airport fully supports its goals of environmental stewardship and sustainability, notes Terry Hart, president and CEO of the Chattanooga Metropolitan Airport (CHA).

The airport's recent projects run the gamut from a solar farm and high-efficiency lighting to preconditioned air units and environmentally sensitive runway coatings. The FAA's Voluntary Airport Low Emission (VALE) grant program has funded nearly $4 million of the efforts, and the airport is working to secure more financial support. CHA qualified for grants from the eight-year-old VALE program because it is located in an air quality nonattainment area for particulate matter 2.5 - particles with an aerodynamic diameter of or less than 2.5 micrometers. 

Sunny Prospects

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Project: Sustainability Enhancements

Location: Chattanooga (TN) Metro Airport

PHASE I SOLAR FARM

Size: 4 acres

Solar Panels: 3,984 Suniva 255-watt, 60-cell panels

Cost: $3.9 million

Funding: 95% VALE; 5% Airport
Completed: Dec. 2011

Grant Application: Leigh Fisher

Emissions Modeling; Glint & Glare Study: Leigh Fisher

Farm Design & Installation: Inman Solar

General Contractor: Pointe General

Electrical Contractor: Young Electric

Civil Engineer: Kimley-Horn and Associates

PHASE II SOLAR FARM

Cost: $3 million

Projected Production: 1.1 megawatts

Status: Awaiting approval of FAA energy efficiency grant

GATE ELECTRIFICATION

Cost: $2.6 million

Equipment: 9 sets

Status: Awaiting approval of VALE grant

Runway LEDs: Siemens; Cooper Crouse-Hinds

Runway Coating: GSB-88, by Gee Asphalt Systems

Other Initiatives: Converting terminal lighting to compact fluorescent bulbs; partnering with city on landscaping-based storm water project

Under the airport authority's plan, CHA will eventually be home to a three-megawatt solar farm. The first phase, completed last December, cost $3.9 million - 95% of which was covered by a VALE grant. The airport authority paid for the remaining 5%, or $180,000.

Phase I work included site preparation and the installation of panels, a monitoring system and inverters and combiner boxes. A four-acre plot in the southwest corner of the airfield made an ideal spot for the solar farm because its runway and road access restricted development for other purposes, notes Hart.

"It really was a piece of land that had absolutely no other value to the airport," agrees Darcy Zarubiak, director with Leigh Fisher. "That's one of the real nice components of this - finding a use for that type of land."

Leigh Fisher performed project formulations, helped engineers understand the nature of the solar project and assisted with FAA/airport interface.

To prepare the site, crews filled in a 25-foot ravine with soil from another portion of the airfield, which was leveled to prepare for general aviation development.

Kimley-Horn and Associates, working under prime contractor Inman Solar, reviewed airspace requirements, verified that the proposed site was located in an area where it would not interfere with airport operations and ensured that the solar farm met FAA standards.

In August, the farm was performing ahead of projections from a return-on-investment standpoint. Phase 1 costs were originally expected to be recovered in less than two years, but CHA had already produced 1 megawatt of energy - well above expectations - in eight months of operation. In addition to supporting the airport's environmental goals, the solar farm augments continual efforts to lower costs for airfield users and make CHA a more attractive option for new entrants, relates Hart.  

Making Solar Work

CHA's solar farm is noteworthy because the airport sells the energy it produces instead of consuming it onsite. "Of the five VALE solar projects, (CHA) is the only one that I'm aware of that has that unique circumstance," notes Zarubiak. In the early stages of the VALE program, the FAA felt that every electron should stay on-airport, he explains.

To do that, however, CHA would have had to spend an estimated $1+ million to run cable from the solar farm to the terminal. The airport instead struck an agreement to sell the energy to the Tennessee Valley Authority, which supplies its power and had an existing grid near the solar farm. Under a 20-year agreement, CHA monitors the amount of solar energy being produced and reports it to TVA each month.

Although the solar farm doesn't directly power the airport, it does help offset its energy costs, explains Hart.

Selling solar power also provides ancillary benefits, he adds: "It gives us the opportunity to produce clean energy for our community, which is consistent with the goals we set forward."

The airport's website provides ongoing statistics about how much power the airport's solar farm is producing. Inside the terminal, a kiosk provides the same information to travelers. This "higher level of community outreach" strengthens the airport's efforts, relates Zarubiak.

The location of CHA's solar farm - outside its object-free area, but inside the airfield operations area - further distinguishes the project, he adds. Other VALE-funded solar projects have placed panels on the roofs of parking garages and a central plant. "This is the first VALE-funded one that went on the airfield," he reports.

Because the control tower at CHA faces the back of the solar panels, glint and glare are not an issue.

Spurred by the success of Phase I, the airport authority is moving forward with a Phase II - another 1.1-megawatt solar farm, adjacent to the first. The airport is currently awaiting approval of a $3 million grant from the FAA's energy efficiency program to help fund the next stage.

If funding is secured and the weather cooperates, Hart expects Phase II to take roughly two months to construct, just as Phase I did. Officials expect that after the second phase is complete, the solar farm will pay for about 80% of the power consumed at the airport.

With more land available, a third phase is also being considered. When and if the airport completes Phase III, officials say, the airport could produce enough solar energy to make it effectively energy self-sufficient and carbon neutral.

Previously, the airport consumed slightly more than 4 megawatts of electricity each year. After initiating conservation measures within the terminal and replacing nearly all of its incandescent taxiway lights with LEDs, the airport reduced its usage by roughly 1 megawatt. Inside the terminal, high-energy light bulbs were switched to compact fluorescent bulbs.

Green Gates

Continuing the string of sustainability efforts, CHA more recently turned to its airside gates. Officials have applied for a VALE grant to assist with the purchase and installation of preconditioned air and ground power units for its air carriers. The project is valued at just under $2 million, of which the airport will be responsible for 10%. In addition to helping the airlines reduce costs and emissions, the units would also provide a new customer service amenity.

"In the summertime, it does get quite warm here and it's nice to have air on that aircraft when it's on the ground," Hart explains. "We felt it was the right thing to do and a good project to take on. We believe good service equates to bringing people back to fly out of this airport, and we want to continue on those efforts."

CHA currently has six gate locations and three remote parking areas. If its grant application is approved, each gate and remote location will offer preconditioned air and ground power units capable of servicing all aircraft types. Currently, Delta Air Lines, American Airlines, US Airways and Allegiant Air operate at the airport.

Leigh Fisher was again contracted to assist with the VALE application. If approved, the airport expects to move ahead with the bid process to secure the equipment.

Municipal Partnership

CHA has also partnered with the city of Chattanooga on a flood and storm water project. When the airport used FAA funds to purchase property on the south end of the airfield, in the runway protection zone, its original intent was to return the area to a green grass site, Hart recalls.

At the same time, however, the city was working to improve the nearby area, including a storm water management project. So the city and airport partnered, demonstrating how a community can sculpt the landscape and use natural plant material to prevent storm water runoff from entering the city's sewer system, Hart explains.

So far, the properties - former car dealership buildings - have been purchased and an agreement that runs through April 2014 has been reached with the city. The airport is currently awaiting grading plans from the city before beginning demolition of the buildings, Hart reports. Other than applying for the grant to acquire and demolish the buildings and staff time to manage the project, no additional costs are expected for the airport. "I think it's a great project that will demonstrate how a community can work with its airport and use green infrastructure to help manage an issue," he adds.

Untapped Opportunity

While the environmental benefits of these projects are significant, the economic benefits should not be overlooked, Zarubiak emphasizes. "You're talking about really big dollars (for) airports the size of
Chattanooga," he says.

Costs for Phase I of the solar farm, for instance, will be recouped in less than two years; but the financial benefits will continue to accrue long after. "While the solar array and gate electrification have made a very meaningful improvement to the environment, they've also made a very meaningful improvement to the bottom line of the cost of doing business at Chattanooga," says Zarubiak.

About 160 of roughly 550 commercial U.S. airports are eligible for the VALE program, he notes. Of those, only 27 airports have participated in the program as of July. "I find that absolutely astonishing," he adds.