During the phone call, Florian Rothenberg is wrapped in a wool blanket. The energy crisis does not only concern him in his profession – he is an emissions trading analyst at the information service Independent Commodity Intelligence Services (ICIS) in Karlsruhe. The high energy prices are also an issue for him in his private life: Because he wants to win the energy-saving challenge of the Karlsruhe municipal utility company and reduce his consumption by at least 20 percent, he hardly heats at all and showers cold. And he wears warm clothes while working in his home office.