Information and Communication Technology (ICT), including data centres, communication networks and user devices, accounted for an estimated 4-6% of global electricity use in 2020. Increasing demand for ICT is expected to lead to an increase in global ICT energy use over the next decade. Experts have highlighted ongoing improvements in the energy efficiency of the technology. However, there is limited evidence on the energy use of ICT, and a significant degree of uncertainty in existing estimates. This POSTnote summarises estimates of the energy used across the ICT sector and trends that may affect it. It discusses developments in energy efficiency and issues related to energy reporting and standards.