Energy consumption in buildings is an important part of the EU energy policy. Until recently, buildings were considered as passive elements in the electricity network that solely consume electricity. The transformation of the today's grid to a Smart Grid is expected to introduce radical changes to the role of buildings in the energy system. Buildings of today will become an active element in the future electricity network and participate in micro-generation, energy storage, vehicle-to-grid and demand response activities. Sweden constructed a large number of buildings in the 60's and 70's within the so called Million Homes Program, which aimed to provide Swedish citizens with 1 million new living spaces with modern facilities in a 10 years period. Buildings of the program have poor energy efficiencies and are reaching an age where extensive refurbishment emerges as a necessity. Large projects for the renovation of such buildings will be conducted in the future, but there are several barriers to them. Cooperation between building and energy sectors is a necessity for not only refurbishing these buildings to become more energy efficient, but also upgrading them to active buildings. This transformation might require the introduction of new actors and business models to markets.