Instead of focusing on the energy optimization of single ICT elements, or subsets of the ICT elements making up a data centre, All4Green broadens the scope of energy savings to the full ecosystem in which data centres operate. The novel approach proposed by All4Green specifically fosters collaboration between all entities in this ecosystem with the common goal of saving energy and emissions (hence the name of the project): ICT users deploying services in the data centre, electrical power providers, and data centres cooperating in a federated way.With the proposed technology, energy savings generated in the data centre through the new relation with ICT users are magnified at the very source of the electricity transformation process through the coordinated collaboration of all the actors inside the ecosystem.The project will demonstrate that this collaboration is not only beneficial for the environment, but also economically sustainable, and therefore not limited to customers with a strong green/ecological conscience.The main benefits of the envisioned ecosystems results from the interplay between data centres and energy providers. On the one hand, data centres, as important customers of energy providers, can have a great impact on the emergence and avoidance of energy usage peaks, and on the other hand, energy providers can reduce the impact of such peaks by using the optimal balance of energy sources based on their flexibility and CO2 emissions, including renewable energy sources like solar or wind, which have traditionally been difficult to be fully integrated into the electricity grid due to their long-term unpredictability.The All4Green project addresses this problem by coordinating energy supply and demand by encouraging extensive collaboration between energy providers and data centres as major energy consumers. This, in turn, is enabled by Green-SLAs in the contracts between users and data centres.