District heating networks are being upgraded and customer numbers are on the rise, as the companies continue to promote energy efficiency awareness... the biomass unit from the Cergy Pontoise heating network, France. (Photothèque Veolia- Stéphane LAVOUÉ) Generation in % TOTAL... through Dalkia Holding company) Électricité de Strasbourg (88 82 % EDF) Tiru (SA 51 % EDF) EDF Trading (EDF 100 %) Data adjusted for the EDF Group' s percentage interest in industry and as energy sources for heating networks, especially in France.