Due to omnipresent digitisation, the energy consumption of information and communication technology (ICT), i. e. of digital end devices, data centres and telecommunications networks, is becoming more and more important. Between 2015 and 2020, the annual energy demand of data centres and transmission grids in Germany increased by around 5.4 TWh. This corresponds to an increase of 30 %. Existing efficiency and saving potentials must be consistently tapped in order to slow down the current growth in consumption. In the TAB report, blockchain applications, private internet use and smart energy management in buildings have been examined in depth.