*Article* **Towards 100 Positive Energy Districts in Europe: Preliminary Data Analysis of 61 European Cases**

#### **Silvia Bossi 1,\*, Christoph Gollner <sup>2</sup> and Sarah Theierling <sup>2</sup>**


Received: 12 October 2020; Accepted: 16 November 2020; Published: 20 November 2020

**Abstract:** Positive Energy Districts and Neighborhoods (PEDs) are seen as a promising pathway towards sustainable urban areas. Several cities have already taken up such PED-related developments. To support such approaches, European countries joined forces to achieve 100 PEDs until 2025 through a comprehensive research and innovation program. A solid understanding and consideration of cities' strategies, experiences and project features serve as the basis for developing and designing the PED program. JPI Urban Europe has been collecting information on projects towards sustainable urbanization and the energy transition across Europe. The collected cases are summarized in a PED Booklet whose update was recently published on the JPI Urban Europe website. Results presented in this paper provide insights from the analysis of 61 projects in Europe and offer recommendations for future PED developments.

**Keywords:** Positive Energy District (PED); PED Booklet; SET-Plan

#### **1. Introduction**

Cities have a strong impact on greenhouse gas production and climate change, and several programs and initiatives are focused on new strategies to transform cities into climate neutral ones [1,2].

The Strategic Energy Technology (SET) Plan, adopted by the European Union in 2008 to establish an energy technology strategy in that region, is focused on 10 key action fields, of which Action 3.2 aims to support the planning, deployment and replication of 100 Positive Energy Districts by 2025 for sustainable urbanization [3].

The Program on Positive Energy Districts and Neighborhoods (PED Program) is conducted by JPI Urban Europe in cooperation with the SET Plan Action 3.2, and it involves stakeholders from city administrations, urban planning, industry, research, and civic society organizations [4]. This is seen as an important contribution to current policies on achieving the goals of reducing Europe's carbon footprint, managing the energy transition, and cities' ambitions towards sustainable urban development. A solid understanding and consideration of cities' experiences and strategies serves as the base of developing the program. This is why the PED program aims at a strong involvement of all stakeholder groups in the program's implementation.

A framework for PED has been defined as follows: "Positive Energy Districts are energy-efficient and energy-flexible urban areas or groups of connected buildings which produce net zero greenhouse gas emissions and actively manage an annual local or regional surplus production of renewable energy. They require integration of different systems and infrastructures and interaction between buildings, the users and the regional energy, mobility and ICT systems, while securing the energy supply and a good life for all in line with social, economic and environmental sustainability" [5]. The primary energy is the performance indicator of the PED definition and the balance includes both

building operations and user-related energy consumptions. Participating PED program partners have agreed that this PED reference framework offers a common baseline across all countries while ensuring flexibility regarding local conditions for PEDs at the same time. Consequently, guidelines for identifying geographical and virtual boundaries of PEDs are still under discussion in collaboration with other programs (i.e., EERA Joint Program Smart Cities) with the ambition of making PEDs achievable for wide range of possible approaches. Examples of PED projects are already under development in Europe in connection with research activities [6–8].

A PED Program mapping of urban projects dealing with the energy transition and sustainability aims to provide an overview of projects, approaches and strategies towards Positive Energy Districts. A compilation of these current cases serves as a basis for knowledge exchange and identification of good practice. The collected cases are summarized in a PED Booklet, an update of which was recently published on the JPI Urban Europe website [9].

Of the 61 cases described in the Booklet, 29 declared a PED ambition. This paper analyses data collected in the PED Booklet to identify common features, strategies, challenges, and success factors of PED projects to guide stakeholders in this field.

For this analysis it must be considered that not all countries have equally contributed to the Booklet yet. The Booklet is based on voluntary contributions from individual PED-related projects and will be continuously updated. Therefore, the results do not allow any interpretation about the level of PED efforts across Europe in general yet.

#### **2. Materials and Methods**

For this study, the 61 cases described in the PED Booklet (later referred to as Booklet) were considered and analyzed. Project descriptions were collected using a template that was sent out to reference persons of each project. The template was organized into 4 sections:


The first question in the "Strategies" section of the template was on goals and ambitions. Among the multiple choices, there was the option "Positive Energy". The cases were divided in two categories: projects that declared a PED ambition (PED, NP = 29) versus projects that did not declare a PED ambition but presented interesting features for the PED Program (Towards (To)-PED, NTP = 32).

The data were collected in an Excel file table and analyzed separately for PED and To-PED. Only features with less than 30% of n/a data were selected as reliable and worthy to be analyzed:


#### **3. Results**

#### *3.1. Geographic Distribution of PED and Towards PED Projects*

The Booklet includes 61 cases in 19 different countries in Europe (Table 1). Of the 61 projects, 29 projects, located in 13 European countries, declared a PED ambition while the rest of the projects (To-PED) are located in 14 European countries.


**Table 1.** Geographic distribution of projects.

The highest number of projects of the Booklet (PED + To-PED) are located in Norway (9), Italy (8), Finland (7), Sweden (6), and The Netherlands (6).

In terms of PED projects, Norway contributed the most cases (8). On the contrary, only two PED/To-PED projects are located in Eastern and Southeastern Europe.

This geographical imbalance may be explained mainly with either of two factors: (1) policy priorities and implementation status of policies towards the energy transition vary between European countries; therefore, specific national programs on PEDs or PED-related matters have only been implemented in some countries. An example is represented by the ZEN Research Centre (https://fmezen.no/about-us/); nine pilot projects were spread over Norway with the aim of developing zero emission neighborhoods [10–12]. ZEN has public and industrial partners to guarantee a multidisciplinary approach that combines together researchers with building professionals, property developers, public authorities, energy companies, building owners, and users. (2) High support of national delegates for the PED Program in collecting information on PED projects in their countries.

#### *3.2. Implementation Status*

The template distributed to projects' representatives included a question related to the implementation status of their projects. Possible choices were: "Planned", "Implementation Stage", "Realized", "In Operation", and "n/a". Percentages of PED and Towards PED projects in different implementation phases are summarized in Figure 1. Most of PED projects (green) are in their implementation stage (69%); 24% are in planning stage and only a minority are realized (3%) or already in operation (3%). To-PED projects (in blue) are mainly in their implementation stage (44%), but also a considerable amount of them are already in operation (31%); 9% are realized but not yet in operation. Only 13% of To-PED projects are in planning stage. As expected, PED projects are less mature than Towards PED projects; among them only one project is already in operation and only one is realized.

**Figure 1.** Implementation status of Positive Energy District and Neighborhood (PED) versus Toward (To)-PED.

#### *3.3. Building Structure*

Differences of projects' building structures were analyzed by dividing them into "Newly Built", "Existing Neighborhood" and "Mixed".

Projects with PED ambition mainly show a mixed typology (Figure 2); 66% of them combine newly built with existing neighborhoods, 28% of them are newly built districts, and only 7% are developed from existing neighborhoods.


**Figure 2.** Building structure of PED versus To-PED.

On the contrary, To-PED projects are mainly based on existing neighborhoods (41%). A considerable percentage of them is based on a mixed typology (38%) and only 16% of Towards PED projects are newly built. A comparison among PED and Towards PED projects is shown in Figure 2.

PEDs results are in good agreement with the framework, which suggests the combination of new urban development areas with existing buildings.

#### *3.4. Land Use*

The Booklet includes information on land use of projects areas. Multiple choices were available for this topic: "Residential", "Office", "Industry", "Commercial", "Social", "Other", and "n/a".

Twenty-three PED and 17 To-PED projects specified a land use and results are summarized in Figure 3a. All the projects (100% of PED and 100% of To-PED) included residential use. In addition to residential use, 65% of PED projects included a social land use versus 29% of To-PED projects. Commercial activities were foreseen in 61% of PED and only in 24% of To-PED projects. More comparable percentages were observed for office spaces (61% of PED versus 53% of To-PED) and industry (22% of PED versus 18% of To-PED). In addition, 30% of PED and 47% of To-PED projects mentioned other typologies of land use (e.g., logistic hubs, natural facilities, waste water energy recovery systems, etc.).


**Figure 3.** (**a**) Land use of PED versus To-PED; (**b**) land use selection of PEDs versus To-PED.

The number of different land use selections were counted for PED and Towards PED projects. The results reflect the degree of mixed use in the projects and were divided into three groups: "single use", "moderate mixed" (two to four land uses), and "highly mixed" (more than five land uses). Comparison results for PED and To-PED projects are summarized in Figure 3b. Only small percentages of PED and To-PED projects have a single land use. A high percentage of PED and To-PED projects have a moderate mixed land use, namely 57% and 76%, respectively. A significant amount of PED projects has a highly mixed use (39%), whereas the same is true in only 18% of Towards PED projects.

#### *3.5. Energy Typology*

The template used so far included a question on "Typology of Energy Supply" where project representatives could select one or more of the following options: "Solar thermal energy", "Geothermal energy", "District heating/local heating", "Heat pump system", "Industrial waste heat", "Photovoltaic", "Other", and "n/a".

Answers to this question where collected for PED and To-PED projects and the results in percentage of total projects with energy data available are shown in Figure 4a. Most of the projects included "district/local heating" in their energy strategy, with similar percentages for PED (75%) and To-PED projects (83%). Several projects included "heat pump system", with 71% of PED and 60% of To-PED projects. Among PED projects, 71% of them exploited photovoltaic energy, while only 30% of To-PED projects used PV. The share of PV use represents the main difference between the two project categories, followed by the use of geothermal energy—58% for PED versus 31% of To-PED. Half of PED use solar thermal energy versus 37% of To-PED; a similar result for PED and To-PED was observed for industrial waste heat (25% and 33%, respectively). Other typologies of energy supplies described by the PED projects included wind, biomass, waste digestion, and hydrothermal.

For each project, we evaluated the number of different typologies of energy supply combined together. Data obtained were classified in four different groups based on the number of energy sources used:


The quantification of multiple energy sources integration for PED and To-PEDs is summarized in Figure 4b. Half of PED projects use "highly mixed" energy sources (4 or 5), 29% are "moderate mixed", 13% are "very highly mixed", and only 8% use just a single source of energy.

Most of To-PED projects are "moderate mixed"; 60% use two or three sources of energy, 30% are "highly mixed", 7% use only a single source, and only 3% use "very highly mixed" energy typologies.

Results suggest that PEDs combine more energy sources (four or five) than Towards PED projects (two or three) to satisfy the energy surplus required. PED projects have the aim of reaching an energy surplus production from renewable energies. Combining a high number of energies is not the aim for a PED but it seems to be a frequent approach of PED projects. PED preferred energy typologies are district and local heating, heat pump systems, photovoltaic, and geothermal energy.

#### *3.6. Success Factors and Challenges of Projects Implementation*

An analysis of the statements regarding success factors and challenges/barriers of PED and To-PED projects (Figures 5 and 6) shows the perceived importance of stakeholder involvement. In fact, involvement processes (urban stakeholders, citizens) can be seen as defining elements for the success or failure of a project. Political support (or lack of it), most likely connected with funding, is seen as another key aspect, especially for PED. Capacity-building among decision-makers can thus be seen as a highly important task. Not only funding, but the elaboration of feasible business models also ranks very high among key aspects of PED development.


**Figure 4.** (**a**) Energy typology of PED versus To-PED; (**b**) energy typology selections of PED versus To-PED.
