The foreseen large-scale deployment of intermittent renewable energy sources (RES) may seriously affect the operation and stability of energy networks. It will, therefore, be necessary to control the energy use to ensure alignment with the instantaneous energy production. The built-in energy flexibility in buildings is an attractive recourse to control energy use due to the relative limited infrastructure needed to operationalize this resource. Mobilizing this currently untapped resource would, therefore, allow for a larger roll-out of RES and make the energy networks more resilient through their ability to shift energy demand in time.

In this context, resilient energy networks are defined as systems that are prepared for and can withstand the challenges associated with the transition to energy systems with a large shares of RES. Energy flexible buildings and communities may increase the resilience of the energy networks by reducing the stress on the infrastructure but also make the buildings and communities more resilient to fluctuations in the energy supply.

The energy flexibility of a building is the ability to manage its demand and supply according to local climate conditions, user needs and energy network requirements. Energy flexibility of buildings is the ability to provide demand side management and/or load control, thus satisfying requirements of the surrounding energy networks and contributing to the resilience of the future energy systems.

During IEA EBC Annex 67 Energy Flexible Buildings, extensive knowledge on how to obtain and control energy flexibility in buildings has been acquired. IEA EBC Annex 67 has also shown that different buildings can provide different types of flexibility services to different types of energy network. This depends on a variety of factors, including the mix of energy from different renewable energy sources. Furthermore, it is not sufficient only to understand the inherent energy flexibility as its usefulness is determined by both the requirements of the surrounding energy networks and by the barriers and motivation of the involved stakeholders such as end-users, building owners, technology manufactures, facility managers, aggregators, distribution and transmission system operators (DSOs and TSOs).

In-depth knowledge of the energy flexibility services that buildings, especially clusters of buildings, may provide and the stakeholder viewpoint on how to use this energy flexibility are essential for the design of future resilient Smart Energy Networks. Understanding the potential of energy flexible services from buildings is important for the utilities who will ultimately utilize this energy flexibility. It is also important for companies developing business cases for products and services that will support the roll-out of Smart Energy Networks, the policy makers involved in shaping the future energy systems and the government entities setting requirements for new and existing buildings.