"It sounds too good to be true," said the Rev. Stephen Planning, president of Jesuit Gonzaga College High School in Washington, D.C., when he heard of a way the school could reduce its carbon footprint, comply with the global Jesuit order's climate push and provide a revenue stream, all at the same time.

The answer was solar panels.

"Laudato Si'," Pope Francis' 2015 encyclical on the environment, has stimulated a lot of discussion in the Catholic Church over how to take up the pontiff's exhortation to respond to global warming. In response to the encyclical, the Jesuits established "Caring for our Common Home" as one of their four universal apostolic preferences.

The encyclical "provided the underlying philosophical, moral and religious impetus" for the school's decision to go solar, said Planning.

"There has been a move on the part of religious institutions, Catholic schools, Jesuit schools in particular, to find ways to respond to the church's desire to extend social justice theory to our planet, and to respond not just as individuals but as an institution," explains Planning.