ESSLINGEN. The Ecoinn Hotel am Campus in Esslingen is now a member of “UnternehmensGrün”, a federal association of sustainably producing companies. UnternehmensGrün is a nationwide alliance of companies, self-employed people and business executives. The association’s aim is to promote environmental protection. It sees itself as a “lobby association” working towards the greatest possible harmony between business and the environment. According to its own figures, the Ecoinn Hotel has already attracted attention with the lowest CO2 emissions per overnight stay in Germany and as the first certified climate hotel.