Let there be solarThe Athenian School celebrated its new solar array system Feb. 11, inviting Danville Mayor Newell Arnerich to flip the switch on the school's new solar array, which was financed by Tioga Energy. The array, which forms a large letter A, is perched on a hillside. It is the size of a baseball field and is one of the largest nonprofit solar power installations in California.
"Environmental stewardship is one of the pillars the school was founded upon," said Eleanor Dase, head of school. "We are excited and pleased to be able to model this value for our students, as well as do our part to use green energy and reduce global warming."
All 450 Athenian School students were in attendance at the event and had the opportunity to ask the project engineers questions about how the solar array works. The installation, a 220-kilowatt system consisting of 1,300 photovoltaic panels and covering 30,000 square feet, was designed and installed by REC Solar and Mitsubishi Electric and financed through a Power Purchase Agreement (PPA) with Tioga Energy. The School expects to save about $250,000, or 15 percent of annual energy costs on average, over the next 20 years.
As construction began on the project, the hillside slotted for the 1,300 solar panels presented a unique engineering challenge. Soil tests confirmed that traditional photovoltaic foundations were not suitable for the existing soil and initially the project team considered replacing the soil on the hillside.
"It raised some serious financial issues," said Bob Oxenburgh, Athenian's director of facilities.
The added cost of replacing the soil nearly scuttled the entire project. "Tioga and REC Solar struggled hard to make this work, and came up with a relatively lost-cost alternative," explained Oxenburgh.
The solution was to design and build 101 concrete piers extending 15 feet into the earth to support the solar array.
Over the next 20 years, the array will avoid generating nearly 12,800 pounds of smog-producing emissions and 66 million pounds of carbon dioxide. The reduction in greenhouse gases alone is the approximate equivalent of taking 55 passenger cars off California's roads each year. In addition to reducing pollutants, the high-efficiency Mitsubishi Electric modules use lead-free solder, eliminating the harmful ingredient commonly used in solder traditionally.