by Emil Morhardt
The main considerations in whether and where to install photovoltaic (PV) panels are how much sun there is, and how much the panels cost. Right? Not necessarily. Engineers at Arizona State University have just published a paper pointing out that if a goal of installing photovoltaics is to decrease greenhouse gas emissions, it would be prudent to consider the emissions from manufacturing—which vary significantly by panel type—how long they stay in the atmosphere, and whether or not the installation is competing with other renewable energy sources rather than with fossil fuel burning. Because of the greenhouse gases associated with manufacturing, all panel installations increase greenhouse effects in the short term, although the initial two-year effect is to reduce them owing to sulfur and nitrogen oxides released from power plants during manufacture.