The "economic sense" of Princeton's $30 million solar fields

Just south of Lake Carnegie, 27 acres of photovoltaic panels collect and convert enough solar energy to account for about 6% of Princeton University’s energy usage every year. These panels cost about $30 million to install in 2012. According to Gina Talt, a Campus as Lab fellow at Princeton’s Office of Sustainability, the university contracted the fields in 2011, because solar energy started to make “good economic sense” around that time.About $10 million of the project was paid for by a federal grant, made available through the American Recovery and Reinvestment Act of 2009. The university is currently selling Solar Renewable Energy Certificates (SRECs) to pay for the rest of the project. SRECs, which represent one Megawatt-Hour of renewably produced energy, are comparable to stocks, in that both are theoretical goods: buyers in the SREC marketplace purchase the renewable energy savings represented by each certificate, not the energy itself.SRECs are valuable because some states mandate that electricity supply companies produce a certain percentage of their energy from renewable sources. New Jersey, for example, requires that 20% of energy sales come from renewable sources by 2020. As a result, utilities that are lagging behind New Jersey’s requirements can buy SRECs from Princeton to make up for the difference in their own emissions savings.At the beginning of April, SRECs in New Jersey were selling at about $220 each, a relative low point for the state. The university expects to stop selling SRECs in 2019 or 2020. Caroline Savage, a Campus as Lab manager at the Office of Sustainability, said that the university saves more on carbon emissions through energy efficiency upgrades than the production of solar energy. According to Savage, solar fields save about 3,000 tons of carbon dioxide per year, whereas upgrading existing energy facilities to be more efficient saves about 5,000 tons of emissions per year.“Solar is definitely fantastic, but the most sustainable unit of energy is the one you don’t consume,” Savage said.When the university stops selling its SRECs, it will start counting emissions savings towards its own goal to reduce campus emissions to 1990 levels by 2020. Disclaimer: Somi Jun is a Communications Assistant for the Office of Sustainability.