The concept of Positive Energy Districts (PEDs) is increasingly transitioning from experimental discourse to implementation-oriented practice within the European context. The ATELIER project positions PEDs not merely as technological innovations, but as systemic instruments for steering urban transformation, with direct implications for spatial planning, regulatory frameworks, and development governance.
As a “fellow city,” Bratislava did not implement a pilot PED in its execution phase; however, it acquired critical methodological frameworks, procedural know-how, and transferable reference models from lighthouse cities such as Amsterdam. Importantly, Bratislava engaged in applied experimentation at the local scale through the development of a PED-oriented energy concept for a site located within the largest prefabricated housing estate in Central Europe. This intervention represents a significant shift from abstract conceptualization toward the operational testing of transformation pathways within existing urban fabrics. It also foregrounds a central challenge: how to translate PED principles into enforceable regulatory instruments and decision-making processes within a specific institutional and spatial context.
PEDs fundamentally redefine the scale and scope of urban energy planning. Energy performance is no longer evaluated at the level of individual buildings, but at the scale of districts, necessitating coordination across land use, building typologies, mobility systems, and technical infrastructure. This implies the integration of four interdependent layers: energy efficiency, decentralized renewable energy generation, storage capacity, and intelligent management systems (smart grids). Consequently, PEDs shift the paradigm from demand reduction toward actively managed, networked energy systems with embedded capacities for energy exchange.
From a planning perspective, a critical implication is that PEDs cannot be retrofitted as an add-on to conventional development processes. Instead, they require early-stage integration within planning frameworks, including zoning regulations, parcel structuring, and land-use programming. This constitutes a reconfiguration of the role of municipalities—from passive regulators toward proactive coordinators of integrated energy-spatial development, operating across sectoral and scalar boundaries.
In the case of Bratislava, brownfield sites emerge as primary spatial opportunities for PED implementation. Their relative structural openness enables the embedding of integrated energy concepts from the outset, while their scale allows for systemic optimization at the district level. The transformation of brownfields into PEDs enables the alignment of urban form with energy performance objectives, the direct integration of renewable energy systems into spatial design, and the deployment of infrastructures supporting energy sharing and e-mobility. Moreover, such sites function as experimental platforms for new governance arrangements, particularly hybrid models of public–private cooperation that are essential for implementation.
Empirical evidence from the REPUBLICA District in Amsterdam underscores the importance of integrated project governance, where a single developer entity coordinates the entire development process—from land acquisition to long-term operation. This model facilitates the optimization of energy systems at the district scale rather than at the level of individual assets. In contrast, the Bratislava context is characterized by fragmented governance structures and limited coordination capacity, indicating a need for institutional innovation and strengthened regulatory instruments.
The principal barrier to PED implementation, therefore, lies not in technological limitations but in the absence of regulatory embedding. Insights from the ATELIER project suggest that cities must adopt energy mapping as a foundational planning tool, enabling data-driven decision-making across scales. Equally critical is the definition of measurable performance indicators—such as district-level energy balance and the share of renewable energy—at the earliest stages of planning. These must be complemented by transparent governance frameworks that structure collaboration between municipalities, developers, and energy stakeholders. Continuous data monitoring and feedback mechanisms are also essential to ensure adaptive management and long-term performance optimization.
Comparative insights from partner cities reinforce the systemic nature of this transition. Copenhagen demonstrates how governance platforms can facilitate stakeholder alignment and implements sustainability objectives within planning processes. Budapest, in turn, highlights the importance of linking strategic policy frameworks—such as SECAPs and climate neutrality targets—with concrete spatial planning instruments and implementation strategies.
A further critical dimension is the integration of energy systems with broader urban agendas, particularly mobility and the social dimension of energy use. Electromobility, demand-side flexibility, and community-based energy models are becoming intrinsic components of PEDs, necessitating a shift toward user-centered and data-informed planning paradigms.
The ATELIER project thus reframes PEDs as comprehensive instruments of urban transformation rather than isolated sustainability interventions. For Bratislava, this represents a strategic opportunity to transition from fragmented, project-based approaches toward an integrated planning model that aligns energy systems, spatial development, and governance structures. The key challenge is no longer whether to adopt PED principles, but how to implements them effectively and at scale—particularly through the transformation of brownfield sites as pilot territories for a new generation of urban development.
Author: Ľubica Šimkovicová, City of Bratislava
Picture credits: Marek Velček