The Commission is in the process of updating some of the content on this website in light of the withdrawal of the United Kingdom from the European Union. If the site contains content that does not yet reflect the withdrawal of the United Kingdom, it is unintentional and will be addressed.

OVERVIEW | Energy Flexibility in buildings

Share this Post:

The EU’s 2030 Framework for climate and energy sets a 40% cut in greenhouse gas emissions compared to 1990, and at least a 32% share of renewable energy consumption, as EU-wide targets for 2030. For the power system, reducing greenhouse gas emissions implies greater electrification, i.e. a greater share of electricity in the total energy mix. It also implies that more electricity should be generated from renewable sources – an increase from 27.5% in 2014 to 45% of electricity demand. Therefore, there will be on the one hand an increased electrification of the energy demand and, on the other hand an increased penetration of renewable energy generation.


Renewable energy sources (RES) like solar and wind are often associated with unpredictability, as their electricity generation varies with weather conditions. This variability brings new challenges, such as a greater need for balancing the electricity grid. In the case of decentralised renewables generation, such as with building-integrated photovoltaics (BIPV), the consumer can choose between self-consumption and delivery to the grid, which adds an element of unpredictability. Generation capacity back-up is therefore usually required to face periods of low generation from RES, while the high fluctuations in the use of these units imply additional fuel and start-up costs. In this context, interconnectors, demand response and energy storage play an important role in increasing system flexibility.


The energy flexibility of a building is the ability to manage its energy demand and generation according to local climate conditions, user needs and grid requirements, thus the building can support the electricity system based on the requirements of the surrounding grids. Domestic hot water storage, electric batteries and smart appliances represent effective solutions for enhancing the energy flexibility of buildings. 


The European energy system is currently under-using a potentially vast source of demand flexibility that could provide multi-faceted benefits to the system, namely the energy generation and demand flexibility of buildings. This is mainly caused by the lack of communication between grid/market and buildings as well as a lack of interoperable intelligent building management systems that can respond to grid or market signals.


Smart buildings are key enablers of future energy systems as they will help to facilitate a larger share of renewables, distributed supply and demand-side energy flexibility. In the revised Energy Performance of Buildings Directive (EPBD), one of the focal points is to improve the realisation of this potential through smart ready technologies in the buildings sector. Therefore, the revised EPBD requires the development of a voluntary European scheme for rating the smart readiness of buildings: the “Smart Readiness Indicator” (SRI).  A Smart Readiness Indicator for buildings provides information on the technological readiness of buildings to interact with their occupants and the energy grids, and on their capabilities for more efficient operation and improved performance through the use of ICT technologies.



A Flexibility-Evaluation-Tool (FET) has been developed within the IEA EBC, Annex 67 – Energy Flexible Buildings. It is an Excel-based tool to uniformly visualize, characterize and evaluate flexibility for different data input sources. The FET can evaluate of energy flexibility with different timesteps, timespans, cost functions/penalty signals based on a reference load profile, a load profile with flexible operation and a penalty signal/cost function. It includes a reduced number of energy flexibility evaluation criteria and indicators and it provides a way to compare results from simulations.


EU Projects

The Syn.ikia project aims at achieving sustainable plus energy neighbourhoods with more than 100% energy savings, 90% renewable energy generation triggering 100% GHG emission reduction, and 10% life cycle costs reduction, compared to NZEB levels. The main strategy for achieving these goals is to deliver a blueprint for sustainable plus energy buildings and neighbourhoods, leading the way to plus energy districts and cities, through (a) demonstrating new designs and efficient operation of sustainable plus energy neighbourhoods; (b) delivering customized designs, innovative technologies, and decision support strategies and tools; (c) encouraging community engagement and empowering user’s control; (d) unlocking the potential of neighbourhoods as flexibility providers; and (e) providing big data-based infrastructure management and smart networks .


Considering that cities have an essential role to play in tackling climate change today, the Positive Energy District (PED) operational models developed in the MAKING-CITY project will help European and other cities around the world to adopt a long-term City Vision 2050 for energy transition and sustainable urbanisation whilst turning citizens into actors of this transformation. It aims to address and demonstrate the urban energy system transformation towards smart and low-carbon cities, based on the PED concept. This project seeks to demonstrate that the PED concept is a real solution for transforming our cities into more sustainable places. The PED, as a district that produces more energy than consumes, generating a surplus that could be shared with other parts of the cities. Other aspects of energy flexibility and new business models for enhancing the energy sharing between different stakeholders are key aspects to optimize the PED and maximize the surplus produced.


On the other hand, the main outcome of the DRIMPAC project is to develop a comprehensive solution to empower consumers to become active participants in the energy market. DRIMPAC aims to bridge the gap of communication between grid/market and buildings by providing a unique and universal technological framework that facilitates the end-to-end communication of the necessary information for the discovery and delivery of demand flexibility. The inspiring objectives of this project are (a) to transform buildings into active participants of the European energy market through the use of intelligent technologies / devices / legislation; (b) to improve building energy efficiency and reduce energy costs via intelligent DR-enabled building management systems; and (c) to unleash the building demand response potential in the EU.


International Projects

The Annex 67 “Energy Flexible Buildings” is a collaborative project supported by the Energy in Buildings and Communities program of the International Energy Agency. It involves around 40 researchers coming from 16 countries and aims to find a common approach for fostering energy flexibility in buildings. Its main objectives consist of (a) development of a common terminology and definition of ‘energy flexibility in buildings’; (b) investigation of user comfort associated with the introduction of energy flexibility in buildings; (c) investigation of the energy flexibility potential in different buildings and contexts; and (d) investigation of the aggregated energy flexibility of buildings and the potential effect on energy grids.


In conclusion, whether it is in relation to the building, the neighbourhood, the district or the grid, energy flexibility requires an interdisciplinary dialogue of sectors to achieve a shift in the peak of energy demand bringing the topic of energy efficiency beyond buildings to their collective interactions within the small and large-scale contexts.


Legend to image 2:

  • (1) Overall inputs for timespan, timesteps, cost-function/penalty function and units
  • (2) Input data about a buildings load profile, a flexible load profile and a cost function based on the timesteps, timespan and units
  • (3) Evaluation charts and characterization