«Green Clouds and Energy Efficient Software» The presentation discusses the impact of cloud computing on designing and building energy efficient software. The focus is on distributed and scalable information systems that employ server clusters and consist of multiple software components. An actual information system is used as an example for discussing details on architectural decisions and ways to improve the "greenness" of distributed cloud-based software systems. The case study is a SaaS (Software as a Service) implementation developed by EBS.gr, current deployed on the Amazon cloud.