The Annex will comprise the following subtasks:

• Subtask A: Building clusters and multi-carrier energy systems for energy flexibility and resilience
• Subtask B: Common Exercise – Flexibility characterization methods and case studies
• Subtask C: Stakeholder acceptance and engagement
• Subtask D: Development of appropriate implementation (business) models

The main part of the activities will be carried out in parallel.

Subtask A: Building clusters and multi-carrier energy systems for energy flexibility and resilience

The single unit “seen” from the grid side is typically not an individual building but rather a feeder (electricity) or a branch of a district heating/cooling system or a portfolio of buildings not physically connected. This entity serves as a cluster of buildings (in the power grid also streetlights, EV charging, etc.), and the grid “sees” the aggregated energy demand of these clusters, rather than individual buildings. Unless a building has a very high energy/power demand, the possible energy flexibility from a building is typically too small to bid into a flexibility market. An aggregation of the energy flexibility from many buildings is thus paramount in order to make an impact. Controlling thermal and electrical storage as well as switching between different energy carriers also increases resilience towards extreme events. The subtask will focus both on single and multi-carrier energy systems, with the aim of developing and testing energy flexibility characterization methodologies and control strategies for clusters of buildings.

The aim is to investigate:

• a methodology (based on the Annex 67 development) to characterize the energy flexibility from different types of clusters of buildings or communities – incl. multicarrier systems
• the available aggregated energy flexibility services from clusters of buildings. Clusters of buildings are areas with existing buildings and in the future also NZEB neighbourhoods, Smart cities, Positive energy districts, also including buildings which are not located in the same neighbourhood but have the same type of energy system controlled by an aggregator – e.g. heat pumps and thus create a virtual power plant
• the modelling and forecasting of the aggregated energy flexibility from clusters of buildings, including the uncertainties from buildings, occupants, climate, etc.
• the control (penalty) signals, which allow for activation of the required flexibility services – e.g. a high penalty during peak periods and low penalty during periods with low demands or plenty of RES in the network
• the development and implementation of the control strategies for obtaining the required flexibility services. The coordination mechanisms developed at district scale will be evaluated
• both theoretical (simulations) and in real life (measurements) of the possible energy flexibility of clusters of buildings located in different energy networks with different needs for flexibility services

Subtask leaders: Rui Amaral Lopes, Nova University of Lisbon, Portugal; Jérôme Le Dréau, La Rochelle University, France.

Subtask B: Common Exercise – Flexibility characterization methods and case studies

The energy flexibility that clusters of buildings can deliver is dependent on many factors, including the number/size of buildings, building use types (e.g., office, multifamily, retail), the energy flexibility technologies and controls, building efficiency characteristics, patterns and variability occupancy, weather, and more.  For example, an aggregator utilizing energy flexibility from buildings does not know exactly how much energy flexibility is available due to a wide range of conditions and features across the buildings, as well as typically one-way communication with the buildings. The aggregator needs to have knowledge of what a given control signal will lead to. This is not simple to obtain as the amount of available energy flexibility cannot be expressed with a single number as it can for energy consumption. However, IEA EBC Annex 67 have suggested a methodology for characterizing energy flexibility by quantifying the amount of energy a building can shift according to an external forcing factor (control/penalty signal). This methodology is based on flexibility functions. The methodology was proven for a few cases in IEA EBC Annex 67, but needs to be enhanced and evaluated for applications to clusters of buildings in Annex 82. Additional methods and approaches may also be needed to support Annex 82 efforts. It is critical that the methods and approaches developed under this Annex be applied in systematic ways that hold constant certain variables while exploring a broad range of conditions for others. In Annex 67, Common Exercises, where various participant teams ran scenarios with common requirements/methods utilizing their own unique tools, building datasets, and climates, proved to be valuable for exploring detailed research questions and developing flexibility characterization methods. Subtask B will be composed of a series of Common Exercises supporting Annex 82.

The aim is to investigate:

• the characterization methodology from Annex 67 using both simulated and measured time series from clusters of buildings
• the flexibility function both from the point of view of the participants own aims and via common Annex 82 research questions
• Annex 82 research questions will be based on the investigated research questions from Annex 67, but further research questions will be developed and investigated via a series of common exercises.
• based on the common exercises the methods and associated calculation scripts for developing flexibility functions will be further developed and mistakes/errors will be corrected, while making the scripts more user friendly

Subtask leaders: Gregor Henze, University of Colorado Boulder, USA (from March 2024); Michaël Kummert, Polytechnique Montréal, Canada (from March 2024); Ben Polly, National Renewable Energy Laboratory, USA (until March 2024); Rune Junker, Technological University of Denmark, Denmark (until March 2024).

Subtask C: Stakeholder acceptance and engagement

There are many stakeholders involved when considering buildings’ energy flexibility. The stakeholders are the occupants/users in the buildings, the owners, energy cooperatives, the caretakers and ESCOs, but also aggregators, utility companies, consultants, manufacturers, local authorities and politicians. The understanding of the motivations and barriers for the different stakeholders is a key input for developing boundary conditions of simulation models or innovative business models for the utilization of flexibility services from buildings and clusters of buildings. The viewpoint of the different stakeholders is also important when developing and designing technical solutions to make these adapted to the user needs. This subtask will mainly focus on the stakeholder’s role in energy flexibility related to the balancing of intermittent renewable energy. However, the subtask also considers the role of stakeholders, such as occupants, aggregators, and energy communities, as a possible flexible resource in mitigating system critical effects related to extreme (weather) events. Some experiences already exist from heat waves in countries like Australia, where the flexibility of building occupants has played an important role in avoiding blackouts.

The aim is to investigate:

• how different occupants and owners of buildings perceive energy flexibility in their buildings
• barriers and motivating factors for providing flexibility services
• barriers and motivations for utility companies and aggregators to utilize clusters of buildings for flexibility services
• barriers and motivations for energy technology providers (e.g. consultants and manufacturers) to develop solutions to optimize flexibility services from clusters of buildings while minimizing the price of the equipment
• how people will react to extreme events with regard to providing flexibility – at one hand in mitigating effects caused by these events or on the other hand adapt to these events
• how the view of the stakeholders can be utilized in the development of feasible technical solutions, e.g. by applying new design approaches such as cocreation and co-design methods

The subtask will involve social scientists as well as technical experts.

Subtask leaders: Toke Haunstrup Christensen, Aalborg University, Denmark; Armin Knotzer, AEE INTEC, Austria.

Subtask D: Development of appropriate implementation (business) models

Annex 67 has revealed that a main motivator for leveraging energy flexibility from buildings is the monetizable benefits for end users and energy service providers. It is, therefore, important to investigate and develop business models where all the stakeholders obtain some kind of monetizable benefit for providing or utilizing energy flexibility.  From a strategic point of view, existing energy networks and building energy systems will require additional investment and service costs. In order to enable a roll- out of the Annex 82 results it is, therefore, necessary to establish sustainable business models that consider the players in a flexible energy network (grid owner, building owners, users, utility or energy service companies, financiers), their value proposition (services, investments) and remuneration system between the different players. Decision-makers also play an important role in enabling policies and establishing  the necessary legal framework for the participating countries.

The aim is to investigate:

• different kinds of business cases from existing case studies both viewed from the consumer and the utility point of view informed by the investigation of the stakeholder motivations and barriers. This includes business cases for building portfolio managers
• the value proposition provided in the networks such as increased resilience and investment deferral in the business models for the different players and the necessary services and investments aligned with the value preposition
• identification of the benefits that energy flexibility provides to utilities, network companies and energy users 
• business model (BM) schemes for different countries and their requirements with specific regard to the needs of building and building cluster managers and business models for multiple energy sources in building portfolios/clusters. Also, BM for emerging technologies which still have not matured but should be considered. With the practical design (required services) Subtask C can potentially contribute to Subtask D
• incentivizing systems for the parties involved should be determined
• besides utilities and ESCOs, some countries have strong market appearances of energy cooperatives which should, if information is available, be evaluated as well
• implementation strategy for pilot case studies (Subtask B) and collaboration with target group interviews conducted (Subtask C)
• the types of legislation that are  necessary to facilitate different types of business models

Subtask leaders: Kim Wittchen, Aalborg University, Denmark; Andy Satchwell, Lawrence Berkeley National Laboratory, USA (until March 2024).