From VW to the airport to Wacker, solar power is lighting the way
There are, on average, 255 days each year in which Chattanooga gets enough sunshine to make use of the greenest energy available: solar. And an increasing number of businesses and even private residents are doing just that.
As early as the 7th century BCE, humans captured the sun’s energy by concentrating it using a magnifying glass to start a fire. In 1839, French scientist Edmond Becquerel discovered the photovoltaic effect, generating electricity when two metal electrodes were placed in a solution and exposed to the sun’s light. Albert Einstein won a Nobel Prize in 1921 for his theories on solar power (this was the same year he published his better-known theory of relativity). In 1954, scientists at Bell Laboratories developed the silicon photovoltaic cell, the first capable of producing enough electricity to power everyday devices. And in 1958, four Earth-orbiting satellites were launched with solar collectors as their source of power.
Yet it wasn’t until the 1970s that Dr. Elliot Berman, working for Exxon Corporation, designed a less costly solar cell, dropping the cost of generating electricity from $100 per watt to $20 per watt. The world took notice and the technological race was on to produce more and less-expensive ways of converting solar radiation into usable electricity for the mass consumption. The race continues today.
Locally, the most talked-about application of solar power occupies 65 acres of property adjacent to the Volkswagen Vehicle Assembly Plant at Enterprise South Industrial Park. Though actually only 33 acres of the land are covered in solar collector panels, it is still the largest single photovoltaic installation in the state of Tennessee.
“As part of our LEED (Leadership in Energy & Environmental Design) certification, on-site green power generation was important, so we explored several different methods,” says Scott Wilson, speaking for Volkswagen. “For instance, using methane generated from a nearby landfill and converting that to electricity. We chose solar for several reasons, including how clean it is and the abundance of sun here in Chattanooga throughout the year.”
Solar power is nothing new to the engineers at Volkswagen. Back in 1982, solar cells were installed on the roofs of Dasher station wagons, generating 160 watts for the ignition system. In Germany, six percent of the nation’s electricity comes from solar. Other VW factories also have solar farms, but none so large as the one in the Scenic City. The use of so much “green” energy was the last piece of the puzzle earning Volkswagen a Platinum LEED certification, the only auto-manufacturing plant to ever do so.
Volkswagen’s solar farm includes 33,600 solar modules from JA Solar, which produce 13.1 Gigawatt-hours of electricity per year. Put into perspective, that’s enough to run 1,200 homes. When the plant is in full operation, the sun provides 12.5 percent of the electricity needed to build the Passat sedan. When the plant is not actively producing cars, the solar generator provides 100 percent of needed power.
Some companies that install solar facilities do so to sell electricity back to the utility. VW consumes all of the energy it produces through use of a sophisticated system of inverters that convert the DC (Direct Current) power that comes from the cells to the AC (Alternating Current) needed by the factory. Volkswagen entered into a 20-year agreement with Silicon Ranch called a “power purchase greement.”
“The solar park,” says Frank Fischer, CEO and chairman of Volkswagen Group of America, Chattanooga Operations, “is another proof point of Volkswagen’s worldwide commitment to environmental protection under its ‘Think Blue’ factory philosophy.”
Also generating electricity from sunshine is the Chattanooga Airport Authority. “The idea began to take shape in 2007,” explains Sarah Stephens, community relations coordinator, “but the solar plan was developed in 2010. Construction on phase one of the solar farm began in October 2011.”
Airports have large swaths of land around the runways and taxiways that by Federal Aviation Administration rules must be kept clear of structures above six feet tall, so they are perfect locations for large, sprawling arrays of solar collectors. The Chattanooga Airport’s solar farm is located on the west side of the airfield, along Jubilee Drive.
“Prior to the development of the West General Aviation Campus this space was unusable for any purpose because of its tendency to flood during heavy rain events,” says Stephens. “When the West General Aviation Campus was developed, a hill had to be removed and that dirt was relocated to this section of the airfield, which raised it above flood level and made it usable land.”
Usable—but not for any aviation purpose. That’s when the idea came up to create a solar farm. Construction was carried out by Inman Solar, utilizing subcontractors from around the Chattanooga area. Nearly 7,500 panels occupy the eight acres of land and generate more than two megawatts of electricity. In fact, more than 60 percent of the airport facility’s power needs are supplied by a sunny day.
Last year the solar cells generated 2,774,883Kwh (kilowatt hours) of electricity worth nearly a quarter-million dollars. This year, as of the end of last month, 1,049,058Kwh have been produced worth more than $78,000. Unlike Volkswagen, which directly uses the energy their solar cells produce, the Airport Authority sells the energy to TVA, then uses the money to pay their bill to EPB. Says Stephens, “All of our solar power is sold to TVA due to the high cost to retrofit the airport terminal building to be able to accept solar power.” This is actually the most common way businesses and even individuals realize their solar dreams. The inverters that convert the energy are very expensive, so it’s just easier and economically more feasible to sell the energy to someone who can readily convert it.
Just the installation of the solar collector cells was an expensive proposition. “Phase I of the solar farm was funded through an FAA Voluntary Airport Low Emission (VALE) Grant,” says Stephens. “VALE Grants are air-quality grants issued to airports that are in non-attainment or maintenance areas. Chattanooga is in a non-attainment area for Particulate Matter 2.5, making it eligible for air quality grant funding.” Phase I’s grant was $4.2 million. Funding for Phase II came from a $3.1 million Energy Efficiency Grant.
At the rate the solar farm is producing energy, it could pay for itself long before the end of its life expectancy, which is 30-40 years. But they may not be finished. “We’re kind of exploring that third phase and how we could make that work,” says Terry Hart, Airport Authority president and CEO. “We do have the land that we could accommodate that with, we’re just trying to work through to see if it makes sense.”
Hart says he would like to see the airport generate all of the power it requires on a daily basis. “We’d love to be able to say that we’re the first airport in the country to be carbon-neutral, self-sufficient on our power.” Standing next to an array of solar collector cells, Hart seems very proud of accomplishments to date and hopeful for the future.
Smaller solar installations around the area include the 212 Market Street restaurant, the covered parking at Finley Stadium and the Riverview Animal Hospital on N. Market Street. Private citizens are utilizing solar energy ranging from the small one-panel installation that keeps their boat battery charged to whole-house packages that effectively take the homeowner “off the grid.” And Chattanooga isn’t only consuming solar power. Just up the road, they’re preparing to help create the devices that actually collect the photons turned into light and motion and sound.
Wacker Tennessee in Bradley County is putting the finishing touches on its $2.4 billion facility, which will produce about 20,000 metric tons of hyperpure polysilicon per year. The plant will employ around 650 people when it reaches full production levels. It will be a “closed-loop” system producing crystaline polysilicon with only one atom of impurities in one trillion silicon atoms. Closed loop also means Wacker will recycle much of the byproduct created in the production of the polysilicon, making it a green company that makes parts for other green companies.
Wacker is the second-largest producer of this material in the world and has hired employees who have studied at Chattanooga State, learning what they’ll be doing when the plant opens for business later this summer.
With recent advancements in the efficiency of solar cells, the lowering cost of installation, and the fact that the sun isn’t expected to burn out for another couple of billion years, it’s not too late to jump on this technology. The sun showers the equivalent of 164 watts of power per square meter during a 24-hour day.
Add it up and that means the sun is radiating 84 Terrawatts (84,000,000,000,000W) per day. And since worldwide consumption is only 12 Terrawatts per day, solar seems to be an increasingly viable solution for a power-hungry planet.