This week, the pope also wrote an article for the Vatican newspaper, L'Osservatore Romano, marking the end of the Muslim holy month of Ramadan, the Italian news agency ANSA reported. This was the first time a pope has done that since John Paul II in 1991.
"We are called to respect the religion of the other, its teachings, its symbols, its values. Particular respect is due to religious leaders and to places of worship. How painful are attacks on one or other of these," Francis wrote Thursday.
In his Twitter feed, @Pontifex, the pope talked of how humans are redeemed by God's love.
"We are all vessels of clay, fragile and poor, but in which there is the immense treasure that we carry," he said.
At the power plant, Francis shook hands with employees. He waved to newspaper staffers who watched from windows, cheering him.