The concept of Positive Energy Districts (PEDs), introduced in the Strategic Energy Technology Plan, is one of the fundamental approaches for a successful, clean and sustainable urbanization by 2025. According to the European Commission, a PED is a set of buildings where the community controls the energy flows and aims at a net positive energy balance over a year by utilizing renewable energy sources. There are a plethora of concepts similar to PEDs, such as Positive Energy Community, Net Zero Energy Neighborhood, Plus Energy Districts, that create a need to establish a structure that can facilitate the definition, development, and precise identification of PEDs. Thus, this paper aims to fill this research gap by comparing these and other related concepts through a critical literature review based on three pillars composing the triangle of sustainability: economic, social and environmental. By doing this, the paper aims to determine the connections between these similar concepts, homogenize the use of terms and avoid the issue of repetitions, which can help draw lessons learnt from other energy‐savings concepts. This study shows how PEDs and Nearly Zero Energy Communities have similar bases, aims and omissions. They diverge in a few key concepts, which can become learning points for PEDs.This article is categorized under: Climate and Environment > Net Zero Planning and Decarbonization Policy and Economics > Energy Transitions Human and Social Dimensions > Energy and Climate Justice

Planning the required energy infrastructure for the energy transition is a crucial task for various neighbourhood concepts, such as positive energy districts. However, energy planning often comes with the challenges of data shortages and a lack of comparability among solutions for different districts. This work aims to enable this comparability by introducing an approach for categorising districts according to parameters that are relevant for the planning of neighbourhood energy infrastructures. Four parameters (climate, floor space index, heating demand and share of residential buildings) and their respective ranges (bands) were derived from the literature. Additionally, this work visualised the combination of all parameter bands across Europe to conveniently showcase districts that are comparable according to the selected parameters. This approach and its visualisation could be used in urban planning to share knowledge from existing energy district projects with those planned in comparable districts.

Global energy systems are undergoing significant structural changes in response to the overarching aim of mitigating and adopting to the geophysical impacts of climate change. One of the key strategies for enabling this structural change is the incremental transition away from fossil fuels and gradual uptake of renewable and low carbon energy sources. While remarkable progress has been achieved in electricity decarbonisation - which contributed around 35% global GHG emissions in 2025, a significant part of the energy system pie is still exploring suitable solutions especially for “hard-to-abate" sectors—such as steel manufacturing, chemical production, and long-haul shipping—where direct electrification is technically or economically challenging. With increased decarbonisation of electricity sectors using variable renewable generation technologies like solar and wind, there is also a growing need to balance and store the wasted energy from intraday supply and demand mismatch. Additionally, increasing severity of climate change impacts globally is accelerating these structural changes where some nation states have also attempted to raise the climate change mitigation ambition by suggesting complete phaseout of fossil fuels at UNFCCC’s COP28 and COP30. Consequently, there is renewed interest in global hydrogen economy and its direct benefits in circumventing majority of the issues highlighted above. Pursuant to this, under the Horizon Europe’s HyWay project, researchers are generating future scenarios for hydrogen economy and analysing the warming impacts of subsequent fugitive hydrogen emissions. In this research, hydrogen economy scenarios are being generating using MESSAGEix-GLOBIOM-GAINS modelling framework of IIASA. The modelling framework generates bottom-up energy system futures for 12 Global regions, while also capturing intra-regional and inter-regional energy commodity trade. The framework generates a least cost solution under various technology transition and climate mitigation constraints using linear programming-based optimisation. Using this framework, we generate a set of scenarios using national implemented policies, nationally determined goals, regional net zero targets, hydrogen generation infrastructure and trade policy data, and different global temperature targets for various Shared Socioeconomic Pathway narratives. In addition, some specialised scenarios also looked at more wide-spread use of hydrogen in the energy system vs. more confined use in industrial clusters. These broad policy and techno-climatic levers along with discussions with key industry stakeholders enabled us to analyse in detail a) the future hydrogen generation configuration at various time steps, b) displacement of fossil-fuels from global energy systems, and 3) sectoral utilisation of hydrogen especially in the industrial sector. Across the scenario solution space, we observe that from a current production volume of 100Mt H2 at a global level mainly for industrial use, hydrogen economy can surpass 400Mt H2 production by 2050 and upwards of 1000 Mt H2 by 2100. This would require significant investment in hydrogen economy infrastructure and possibly underwriting and repurposing of fossil fuel-based energy generation units. We also observe that from current domination of “grey hydrogen”, the energy system will transition completely to “green hydrogen” generation by 2050, with “blue hydrogen” acting as a transition enabler. The results also provide significant insights into regional and global dynamics of hydrogen economy including its climate impacts.