In the GREEN module, partic­i­pants learn to take a holistic view of the topic of green software. This begins with an exami­nation of the role of IT in halting climate change, an intro­duction to current regula­tions, a view of the requirements of various stake­holders and the identi­fi­cation of fields of action in companies. From there, we move on to measuring and monitoring CO2 emissions and energy consumption and on to the core topic of software devel­opment. This central topic area includes the energy efficiency of various software archi­tec­tures and basic concepts used, energy-efficient data handling, optimised algorithms and also the influence and management of quality requirements in relation to energy efficiency. Another important component is the topic of the cloud, both in terms of provider selection and the possi­bil­ities for low-CO2 operation. Finally, options for improving energy efficiency in the devel­opment process are considered.