*2.2. Organisation and Methodology of Annex 83*

From various projects (as shown in Table 1) it is found that firstly, for each project, there is a certain definition of the concept, framework, and key performance indicators which are defined and laid down based on the local conditions and regulations, etc. Secondly, the technical framework, technology such as buildings, renewable energy sources, storage technology and simulation models are defined. Thirdly, the socio-economic and social impact assessment criteria are defined. Fourthly, the real physical PED demo is

planned, implemented, operated, and measured. Lastly, the outcomes and learnings are communicated for future learnings. A similar method and approach is used to design the Annex 83 project plan and is communicated in this paper.

The Annex 83 is divided into four subtasks: Subtask A: definitions and context; Subtask B: methods, tools and technologies for realizing positive energy districts; Subtask C: organizing principles and impact assessment; and Subtask D: demos, implementation, and dissemination.

Each subtask has a subtask leader (or co-leaders) and a vice-subtask leader. The subtask leaders meet regularly to ensure a good coordination and communication between the tasks. This is imperative since many of the activities and results are dependent on the other tasks. *Buildings* **2021**, *11*, x FOR PEER REVIEW 10 of 18

#### **3. Activities, Subtasks, and Expected Results in the Annex 83 3. Activities, Subtasks, and Expected Results in the Annex 83**

The Annex 83 execution phase started in December 2020. This chapter describes the expected results in the four-year project. The expected results are divided into the four subtasks but highlight the need for interaction between the subtasks. Annex 83 integrates work done in other projects and initiatives (see Table 1) through workshops, questionnaires, discussions, and joint publications among the experts who are working on the different projects. On the European level, the main PED-related activities are within the SCC1 projects under the framework Horizon2020. EERA Smart Cities is an active European platform for the collaboration among researchers within the topic of PEDs. The Annex work helps to share lessons and sets a stage for scientific discussion, bringing forward the lessons from projects and initiatives on a global level. The Annex 83 execution phase started in December 2020. This chapter describes the expected results in the four-year project. The expected results are divided into the four subtasks but highlight the need for interaction between the subtasks. Annex 83 integrates work done in other projects and initiatives (see Table 1) through workshops, questionnaires, discussions, and joint publications among the experts who are working on the different projects. On the European level, the main PED-related activities are within the SCC1 projects under the framework Horizon2020. EERA Smart Cities is an active European platform for the collaboration among researchers within the topic of PEDs. The Annex work helps to share lessons and sets a stage for scientific discussion, bringing forward the lessons from projects and initiatives on a global level.

The annex aims to achieve a shared and internationally viable PED definition through a synthesis effort between the previous experiences, to develop new and integrated modeling approaches of PEDs through different techniques and resolutions, develop methodological advances to the sustainability assessment of PEDs, and test in real district environments the knowledge developed. The annex aims to achieve a shared and internationally viable PED definition through a synthesis effort between the previous experiences, to develop new and integrated modeling approaches of PEDs through different techniques and resolutions, develop methodological advances to the sustainability assessment of PEDs, and test in real district environments the knowledge developed.

The interdependencies of the four subtasks are shown in Figure 3. The interdependencies of the four subtasks are shown in Figure 3.

**Figure 3.** Subtask dependencies.

Annex 83.

#### **Figure 3.** Subtask dependencies. *3.1. Subtask A: Activities and Planned Methodology*

*3.1. Subtask A: Activities and Planned Methodology* This activity will start by identifying the main aspects in the definition context, including system boundaries, different localities, timeframes, energy carriers, etc. The PED

This activity will start by identifying the main aspects in the definition context, including system boundaries, different localities, timeframes, energy carriers, etc. The PED

Subtask A will examine the evolvement of the PED concepts and outline the crucial topics in the development of PEDs such as the spatial and temporal scales to be considered, essential technologies and system components, and regulations and implementation barriers. Visualization of PEDs in the form of infographics will be developed to enhance understanding of the PED concept. In addition, the stakeholders usually involved in the

while including the crucial elements. Furthermore, a literature review will be conducted to map the existing studies, projects, and initiatives at the international level. This task will be conducted in collaboration with other subtasks to align the scopes and foci within

scope will be then defined to narrow down the focus in this Annex, so that it is practical while including the crucial elements. Furthermore, a literature review will be conducted to map the existing studies, projects, and initiatives at the international level. This task will be conducted in collaboration with other subtasks to align the scopes and foci within Annex 83.

Subtask A will examine the evolvement of the PED concepts and outline the crucial topics in the development of PEDs such as the spatial and temporal scales to be considered, essential technologies and system components, and regulations and implementation barriers. Visualization of PEDs in the form of infographics will be developed to enhance understanding of the PED concept. In addition, the stakeholders usually involved in the development of PEDs will be identified and categorized. These stakeholders can be urban planners, decision makers, energy system operators and planners, investors, construction companies, housing cooperatives, inhabitants, NGO's, etc. The stakeholders are a fragmented group with varying interests and levels of knowledge about energy and sustainability topics. A framework will be defined for different objectives of PED from different aspects of energy, economics, environment, and social context. Both the stakeholders and the objectives will be input into the Subtask C activities. Meanwhile, the KPI framework for PED will be finally developed in order to compare the performance of the different PED archetypes and PED solutions (developed by Subtask B) and define assessment models (Subtask C).

Based on case studies, common characteristics will be identified and summarized in a "Reference" PED or PED archetype. The "Reference" PED will be used for simulation and demonstration in other subtasks throughout the Annex. Moreover, this activity also plans to establish a common process flow for PED development, using the "Reference PED" as a case study to guide the development of PED projects.

#### *3.2. Subtask B: Activities and Planned Methodology*

The objective of Subtask B is to review which methods, tools, and technologies are necessary for realizing PEDs. The work is divided into three sub activities: B1, aimed at mapping the technical solutions (energy systems, infrastructures, etc.); B2, investigating how flexibility can help to balance the energy flows; and B3, identifying data and tools for modelling PEDs. The latter will model from two to three case studies to demonstrate different control strategies at the district level.

From the case studies identified in subtask D, an inventory of the current PED technologies applied in PEDs will also be analyzed in sub-activity B1. Through this exercise, the needed data for modelling and the best experiences of the different technologies will be identified. From the revision and analysis of the different technologies applied, the technologies can be classified into different topics/areas (heating, cooling, electricity, storage) and scopes (building, district, city). In each topic/area the technologies can be compared and evaluated (using KPIs from subtask A and assessment evaluation from subtask C) in terms of costs (LCoE, etc.) and regulatory, environmental, energy efficiency, and social acceptance indicators, among others.

The focus of sub-activity B2 is to investigate how flexibility management can help to balance energy flows within and beyond the PED boundaries. To do so, different decisionmaking processes (algorithms) and control strategies will be reviewed. The results from the previous task (B1) and demo cases (Subtask D) will highlight and reveal the practical challenges regarding the implementation of smart solutions at different levels, and also future research and development needs in PEDs.

This activity will conduct a literature review on decision-making process (solutions for decision makers, architects, citizens, energy experts, etc.) such as algorithms for planning a PED.

A literature review on control strategies and algorithms will be conducted from the information obtained in Subtask B1 and Subtask D. Research on data analysis techniques and control strategy techniques (more advanced control systems, forecasting, load shifting, peak saving, demand management, virtual power plants) is needed and will be conducted. Other issues, such as demand response, flexibility, and data management (block chain) which are useful for managing a PED will be considered. The result will be a comprehensive inventory of the different control solutions (depending on the technology) that can be applied at the building, district, and city levels. The different control strategies will be assessed to identify the barriers/enablers of the different smart solutions.

The focus of sub-activity B3 is to investigate and identify the data and tools for modelling a PED (from demand to the energy balance calculation) that can be used for designing and operating a PED. Activity B3 will mainly focus on data libraries and how these libraries can be used to model a PED. The idea is to generate a framework on how to standardize libraries for urban/district data models (such as City GML) and how to structure it.

To validate these urban scale models and to use data from subtask D case studies, the libraries from B3 will be used for modelling district scale case studies. To do so, existing tools and city platforms such as INSEL or City Energy Analyst, will be used. This will help to analyze how to extract attributes from data libraries, to parametrize urban scale models, and to apply different control strategies and assess them.

The result of sub-activity B1 will be a guideline of the best technologies applied in PEDs in different urban scenarios. As an output, sub-activity B2 provides ideas for the PED planning phase by city planners, citizens, etc. Furthermore, a prototype implementation of interface algorithms for decision-making solutions for PED will be developed. Finally, a report on urban scale modelling of PED districts (control-focused) and how flexibility management can help to balance energy flows within and beyond the PED boundaries will be carried out in sub-activity B3. Moreover, as an output, open-source libraries will be created.

#### *3.3. Subtask C: Activities and Planned Methodology*

The objective of Subtask C is to investigate potential sustainable pathways towards PED implementation. It aims at investigating both the impact assessment perspective as well as the organizational aspects within PEDs: the idea is to investigate through a harmonized and parallel approach the three different dimensions of sustainability (economic, environmental, social) of PEDs while ensuring that all three directions are developed through cultural contaminations and connections among them in a holistic and integrated way.

The activities are organized within a common framework that develops on three different levels, following the approach towards the sustainability of PEDs. The structure is vertically integrated.

The three major sub-activities are respectively:


The sub-activity C1 will investigate the potential of economic impact assessment methods for PED development and investigation. Key Performance Indicators (KPIs) will be used and tested for PEDs and market strategies and initiative potential will be assessed. Particular interest will be paid to renewable energy self-consumption models that are based on sharing and trading (and financing) approaches.

The development of the activity will also encompass the listing of the most relevant stakeholders to mobilize through the use of organizational models as well as the main barriers and drivers to the implementation of PEDs from an economic perspective.

The sub-activity C2 focuses on the environmental impacts of PED, taking into consideration the different stages of the life cycle of PEDs (e.g., construction, operation, end-of-life). To do so, various factors will be considered, both related to abiotic elements, as well as biotic. The sub-activity will face the challenging task of framing impacts within adequate time limits and scales by identifying relevant boundaries, such as environmental impacts, which widely vary, from climate change to local air quality or biodiversity. More likely,

PEDs are going to deliver a combination of environmental benefits hardly able to be isolated. On the other hand, to realize a PED, regardless of whether they are done by new buildings or the rehabilitation of an existing brownfield, new technologies are going to be installed and natural resources consumed. Therefore, unwanted impacts on the ecosystem may arise and resources consumed. Adequate KPIs and assessment tools are going to be selected and applied to cope with this, and also the life cycle environmental perspective has to be taken in consideration in order to identify potential trade-offs and avoid burden shifts across impact categories or life-cycle stages.

The sub-activity C2 will investigate positive and negative impacts arising from the implementation and diffusion of PEDs, their social acceptance and social inclusiveness. It will also address organizational models and stakeholder engagement in PED development. Once again, social impacts are expected to be found at different levels, from the single householder (e.g., enhanced well-being due to improved indoor comfort) to the local community (social cohesion, social capital) or on a larger population. The peculiarity of the PED's energy system, calling for advanced and innovative solutions, energy sharing and synergies among prosumers, but also implying some behavioral changes due to new technologies, is an interesting and so far unexplored research field for social scientists. Social impacts may be much more relevant as in previous smart energy transition projects and needs specific KPIs. This includes both positive as well as unwanted negative impacts, as, for example, gentrification because of an enhanced attractiveness of the district.

The main outcome of this subtask is to perform the synthesis of the lessons learned and methodological developments by integrating the outcomes of previous ones into innovative and interdisciplinary KPIs—connected to the three spheres of sustainability and develop sustainability inspired early design tools. Such tools may be based on life cycle sustainability assessments or consider multiple benefits to provide evidence of the contribution of PEDs toward the achievement of selected sustainable development goals.

A PED early design tool for sustainability assessment will be offered to support the decision-making process of policy makers and stakeholders, and also try to leverage investments (e.g., by exploiting the impact investing approach). Substantial collaboration will be carried out with other subtasks and case studies.

#### *3.4. Subtask D: Activities and Planned Methodology*

Subtask D spans all the objectives by testing and demonstrating their operationalization in demonstration cases, reaching objective 5 to develop the needed information and guidance for the planning and implementation of PEDs, including both technical planning and urban planning. This includes economic, social, and environmental impact assessment for various alternative development paths.

Firstly, the subtask will start the work with the scoping phase, with the aim to create a framework for data collection from demo cases. References to other initiatives (e.g., SCIS, JPI UE Booklet, and other references from outside EU) will be considered in order to take inspiration for creating the data collection framework collaborative process and to fix the main aspects to be built upon.

The data collection framework will be further elaborated into a template, which will be structured to collect relevant information from demo cases. This activity has a twofold purpose: identifying relevant demo cases and creating a knowledge mass for the whole Annex.

A demo case call will be launched periodically (every 6 months) for the Annex partners and supporters to identify demonstration activities at building blocks, districts, and city levels relevant to the Annex. These can be related also to non-PED demonstrations as long as they show a concrete value for the Annex activities. This is needed to gather detailed information on the best practices, KPIs, stakeholder assessment data, technological data, and key learnings from practical sites.

Secondly, the main outcomes of subtasks A, B, and C will be elaborated into a collection of cross-domains best practices accessible for professionals, city planners, and municipal stakeholders. They will be consulted in the early stages of this activity to identify their burning needs and where they would need support for planning PEDs. This will give an input to create the PED value chain from design and construction to operation, verification, maintenance, renovation and end of life, etc. The guidelines will support the PED planning in different dimensions: urban, suburban, and rural. The integration of PED in the existing urban environment and its role in the city energy transition will also be addressed.

Lastly, a communication and dissemination plan is created with the purpose of outlining the communication, networking, and dissemination strategy, identifying relevant initiatives (associations of cities, professionals, research organizations, initiatives organized by institutions, etc.) for the Annex, describing how the Annex intend to keep up the communication and networking activities. In this regard, the Annex Subtask leaders and Operating Agents will nominate a set of ambassadors to be Annex representatives to the selected initiatives. They will be responsible for setting up collaborative interactions and cooperation events.

As discussed in Section 1, the Annex will seek continuous collaboration with other networks, projects and IEA tasks/Annexes. It is planned to periodically (every 12 months) launch initiatives and conference scouting calls for the Annex partners and supporters to map the relevant PED communication and dissemination opportunities. Under subtask D, the responsibility for all the latest information, updates, relevant content, and outcomes from all the subtasks will be communicated through the Annex website.

#### **4. Discussion and Conclusions**

PEDs are seen as an ensemble of buildings of different typologies and functions (residential, commercial, industrial, public-owned, etc.) that are interconnected and produce more energy than what is needed to cover the buildings' demand on an annual basis. Whether the energy demand of the infrastructure (water and waste management, transportation, street lighting etc.) should be included in the PED demands calculations, and the mapping of the boundaries is a topic for discussion. So far, only the building's energy demands have been considered.

Becoming a PED is seldom the overall goal of a district being planned. Elements to be considered (e.g., the type of Renewable Energy Source (RES), number of buildings, etc.) and characteristics to be investigated (how it is organized, what is the governance model, etc.) should be selected and adjusted according to the main objectives and aims identified for creating a PED (improving the circular economy, ensuring high quality of life, etc.) beyond the technical goal of optimizing the energy balance.

Depending on the selection and the definition, the calculated annual energy balance will change. However, currently, all Energy Performance of Building Directive (EPBD) and building standards such as ISO52000 are applied at the building level, not at the district level, making calculation of the annual energy balance more complex and subject to interpretations.

The elements considered within the boundaries will determine how the Positive Energy District (PED) is defined and which loads should be considered for the calculation. The majority of PEDs in Europe apply the dynamic-PED concept, with geographical boundaries (such as PEDs in the projects ATELIER and MAKING-CITY as mentioned in Table 1), which means that buildings are close to each other and dynamically exchange energy (consuming and producing) with the energy grids. However, it is true that, when no space is available within the district boundaries, it could be useful to apply detached geographical patches or virtual boundaries. The main concern when applying the latter is the ownership of the energy solutions and the business models of trading energy to the PED over the virtual boundaries and how to guarantee the energy origin.

An effort to solve these challenges was done in the Sustainable Energy Positive & Zero Carbon Communities (SPARCS) project (as mentioned in Table 1). To upgrade the interaction between energy producing, storing and consuming entities, a virtual positive energy community is created. It is understood as a "variety of energy related actions virtually connecting the multiple buildings across the district on various locations within and across

the city". The entities can exchange energy based on "advanced control functionalities and dedicated communication channels (Information and Communications Technology (ICT) model, block chain infrastructure and prediction of the demand)".

Some European projects are treating the PED concept in a different way. For example, the MAKING-CITY project (as mentioned in Table 1) characterized their PEDs by local renewable energy systems (RES) that interact dynamically with the grids (thermal and electrical) and are located within the district boundaries, and aim to achieve an annual positive energy balance incorporating building-related consumption. To do so, retrofit measures to improve the energy efficiency of the buildings as well as including mature technologies such as photovoltaics (PV), photovoltaic-thermal hybrid collectors (PVT), building-integrated PV (BIPV), PV on water, waste digestion, geothermal heat pumps, district heating, and thermal energy storage (such as boreholes, seasonal storage tanks, etc.) are implemented. The concept will be tested in the two lighthouse cities (LH), Groningen and Oulu, and replicated then in six follower cities (FC), taking into account the city needs and priorities, on-site resource availability, MAKING-CITY PED (as mentioned in Table 1) solutions and their business models through a decision-making journey emphasizing citizen engagement. The ATELIER project (as mentioned in Table 1), on the other hand, has two LHs, one district in Amsterdam and another one in Bilbao, with a number of very ambitious building groups (retrofitted and new) of different typologies (tertiary, residential, etc.) that are connected by means of grids (thermal and/or electric ones). Amsterdam will participate and interact with the existing energy communities, as well as with the grid, and will use the local waste for the production of biogas. Bilbao will retrofit an industrial old district and connect its buildings with a geo-exchange loop. In a similar way as in MAKING-CITY (as mentioned in Table 1), it will include Renewable Energy Source (RES), retrofit building measures, electro-mobility and digitalization. Both follow the Smart Energy Transition (SET) plan short definition, but their approach to replicate the concept in FCs is made in a softer way, allowing each city to adapt the PED definition to their own urban context.

Furthermore, several European networks are actively working on the topic of positive energy districts. These include JPI Urban Europe, a network of European funding agencies actively promoting and funding projects on Positive Energy districts, the Urban Europe Research Alliance, a network of Research Organizations and Universities closely working with and informing JPI Urban Europe, the Joint Program Smart Cities of the European Energy Research Alliance (EERA JPSC), the group of the European Smart City Lighthouse Cities, and the COST (European Cooperation in Science and Technology) action on Positive Energy Districts. All of the European members of IEA Annex 83 are also involved in at least one other initiative. This creates huge potential for collaboration, and many synergies will be created by organizing joint meetings and conferences and by writing joint publications and policy guidelines.

As discussed above and in Table 1, most of the districts and projects are under construction that can represent PEDs. However, few of the districts are partially operational, as shown in Table 1. For instance, the drake landing solar community (DLSC) in Canada is able to meet around 96% of the space heating demand of the district via renewable (solar) energy and seasonal storage. The Flexens project in Åland is aggressively targeting to meet 100% of the demand using renewables and to become a fossil-free island. Under the Quartier la fleuriaye project in Carquefou, currently 6000 m<sup>2</sup> of the roof area of the buildings (almost 300 houses) in the district are populated with the solar photovoltaic panels, which cover almost 80% of the energy demand of the district. It is planned to increase the total covered area of 15,000 m<sup>2</sup> (almost 600 h) to provide excess energy to the district so that it can become a PED. Similarly, under the Zero Energy District Accelerator project in Arvada, Colorado, the buildings in the district are designed to be zero energy and as a result the building's life cycle costs are lower than the traditional buildings. Therefore, the building owners are saving not only in terms of reduced emissions, but also in terms of electricity price inflation and tax incentives. The owners are open to invest in new

technologies such as passive building design, solar panels and ground source heat pumps etc., to become better.

The challenges raised above in the introduction section indicates that the PEDs are complex and multi-disciplinary in nature. Moreover, it has various challenges depending on the climate, location, regulations, technologies, key performance indicators, and urban context etc., and this requires a scientific global discussion. Many learnings can be done by exchanging experiences from different projects, knowledge, and cases around the world.

In the future, climate adaptation will become more important, which will bring new challenges to the planning of the urban environment and PEDs. Energy poverty might also become a bigger challenge than today due to increased immigration levels caused, among other things, by climate change. The detailed definition, key performance indicators and framework of PEDs will be discussed, developed and published in the future work as the Annex 83 progresses up until 2024. Moreover, all the issues, challenges, methodologies, technological solutions, and roles of the stakeholders will be discussed and developed under the subtasks (mentioned above) which will carried out in Annex 83.

Annex 83 is the main platform for this scientific discussion in the coming years. Different urban contexts will be covered in the different subtasks within Annex 83 to create a global framework of the concept, as well as to identify the barriers and enablers of PEDs. This will be possible thanks to cooperation between the partners involved in the Annex, with expertise from different fields and from all over the world. Canada, with the involvement of Concordia University, will give a perspective on urban scale modelling. Japan, thanks to Tokyo University, will give an overview of the different decision-making methodologies and on flexibility management. Different expertise from Europe and around the world, with the involvement of key actors and coordinators of current PED projects, will contribute to translating theory into practice and to test on the ground the latest findings.

**Author Contributions:** Conceptualization, Å.H., H.U.R.; methodology, Å.H., H.U.R.; investigation, H.U.R, Å.H., A.G., A.B., V.A.-S., X.Z.; resources, Å.H., A.B., V.A.-S., X.Z., A.G.; writing—original draft preparation, Å.H., H.U.R.; writing—review and editing, H.U.R., Å.H., A.G., A.B., V.A.-S., X.Z., F.G., U.E., S.G., H.-M.N., F.R., P.T.; visualization, H.U.R.; supervision, Å.H., H.U.R.; project administration, Å.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding. The authors would like to thank the VTT Technical Research Center of Finland (Finland), Eurac Research (Italy), the technology research center of CARTIF, Fraunhofer Institute for Solar Energy Systems (Germany), Swedish Energy Agency (Sweden), University of Palermo (Italy) for providing the resources, technical, and administrative support.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

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