This study investigates the integration of green hydrogen into building energy systems using local solar power, with the electricity grid serving as a backup plan. A comprehensive bottom-up analysis compares six energy system configurations: the natural gas grid boiler system, all-electric heat pump system, natural gas and hydrogen blended system, hydrogen microgrid boiler system, cogeneration hydrogen fuel cell system, and hybrid hydrogen heat pump system. Energy efficiency evaluations were conducted for 25 homes within one block in a neighborhood across five typological house stocks located in Stoke-on-Trent, UK. This research was modeled using a spreadsheet-based approach. The results highlight that while the all-electric heat pump system still demonstrates the highest energy efficiency with the lowest consumption, the hybrid hydrogen heat pump system emerges as the most efficient hydrogen-based solution. Further optimization, through the implementation of a peak-shaving strategy, shows promise in enhancing system performance. In this approach, hybrid hydrogen serves as a heating source during peak demand hours (evenings and cold seasons), complemented by a solar energy powered heat pump during summer and daytime. An hourly operational configuration is recommended to ensure consistent performance and sustainability. This study focuses on energy performance, excluding cost-effectiveness analysis. Therefore, the cost of the energy is not taken into consideration, requiring further development for future research in these areas. ... Read more

As climate change develops, with most of the world population living in urban areas, decarbonisation of cities is among the greatest challenges of the coming decades. In the framework of the EU City-zen project, a number of so-called Roadshows has been organised in ten cities within and outside Europe in order to plan and kick-off their transition towards an energy- and climate-neutral economy. During the Roadshows, a group of experts is engaged to perform co-working activities and participative labs involving local stakeholders. These activities support cities in identifying their own decarbonisation pathways, mainly by combining three mutual processes, i.e. energy design, urban design and carbon accounting. The latter, in particular, has been used to quantify the greenhouse gas emissions of cities and neighbourhoods and to estimate the mitigation effect of a combination of measures towards the desirable condition of carbon neutrality. This exploratory and proactive design process has been successfully demonstrated through intensive workshops and can be potentially replicated in other cities. This paper provides a schematic overview of the main results achieved in the Belgian town of Roeselare, but more significantly it describes the techniques needed to make that cooperative process understandable, impactful and implementable. It is likely that 2050 European goals will drastically change urban environments and socio-economic dynamics in cities, due to the fragmentation of energy sources. Hence, from this standpoint there is a vital need for integrated technologies and infrastructures, a circular economy and community-based processes such as food production, sharing of facilities and valorisation of ecosystem services.

The City-zen Roeselare Roadshow brought over 300 stakeholders into the process of re-imagining and visualising their 2050 future city with these solutions. Stakeholders, with no particular expertise in carbon accounting or sustainability, would now have the capability of understanding and applying these solutions in a combined effort to meet the zero-carbon challenge. The approach is generally replicable elsewhere being highly visual, impactful, transferable, and multi-stakeholder friendly. Given that data are made locally available, the combination of this general approach, site-specific assessments and the involvement of both experts and local stakeholders (i.e. policy makers, citizens, etc) allow the transition to start by referring to any real city or neighbourhood. ... Read more

The natural ecotone between people, community and carbon reduction is the zero-carbon community. Over recent decades, the design of zero-carbon communities has focussed too greatly on carbon emissions and not enough on building communities. Anthropogenic climate change is a human problem, yet people are seldom placed at the centre of design solutions. The City-zen Roadshow is an intensive co-creational approach to creating zero-carbon communities, which places stakeholders at the very centre of the design process. The methodology uses an ‘urban-first’ approach and champions urban design as the main driver to deliver change. Carbon accounting and energy analysis sit in adjacency with the urban design proposals to deliver interventions that are net zero-carbon, low energy, low waste, socially rich, ecologically diverse, economically robust, resilient, fit for purpose and engaging. The paper describes this novel approach using one roadshow as a case study to illustrate the urban interventions proposed. Living in zero-carbon communities is not just about photovoltaic panels and wind turbines. It is, instead, about thinking differently about the way in which people live and the decisions they make, to provide people with alternative ways of living that are more desirable than those currently available. ... Read more

Purpose: City-zen is an EU-funded interdisciplinary project that aims to develop and demonstrate energy-efficient cities and to build methods and tools for cities, industries and citizens to achieve ambitious sustainability targets. As part of the project, an Urban Energy Transition Methodology is developed, elaborated and used to create Roadmaps, which indicate the interventions needed to get from the current situation to the desired sustainable future state of a city. For one of the partner cities, Amsterdam, such a Roadmap was developed. The paper aims to discuss these issues. Design/methodology/approach: This paper discusses the approach and methodology behind the City-zen Urban Energy Transition Methodology, with its six steps from the initial energy analysis to the roadmap towards a desired future state. The paper will illustrate this by results from the Amsterdam Roadmap study, in numbers and figures. Findings: The Roadmap study of Amsterdam revealed that the city can become energy neutral in its heat demand, but not in the production of sufficient electricity from renewables. Research limitations/implications: Although as yet only applied to the City of Amsterdam, the methodology behind the roadmap can be applied by cities across the world. Practical implications: An enormous effort is required in order to transform, renovate and adapt parts of the city. It was calculated, for instance, how many energy renovation projects, district heating pipes and photovoltaic panels will be annually needed in order to timely become carbon neutral, energy neutral and “fossil free”. Social implications: The technical-spatial content of the Roadmap was presented to stakeholders of the Dutch capital city, such as politicians, energy companies, commercial enterprises, and not least citizens themselves. Although informed by scientific work, the Roadmap appealed too many, demonstrated by the extensive media coverage. Originality/value: The City-zen Methodology builds upon earlier urban energy approaches such as REAP (Tillie et al., 2009), LES (Dobbelsteen et al., 2011) and Energy Potential Mapping (Broersma et al., 2013), but creates a stepped approach that has not been presented and applied to a city as a whole yet. As far as the authors know, so far, an energy transition roadmap has never been developed for an entire city. ... Read more

Following the Paris Climate Agreements, all European cities must undergo a transition towards asustainable, net zero-carbon energy system. This is an unprecedented challenge that will require a lot of knowledge and methodological support.For the City-zen project, under the coordination and execution of TU Delft, chair of Climate Design & Sustainability, as task within City-zen (WP4, T2), the City-zen Urban Energy Transition Methodology (in short: City-zen Methodology) was developed and tested on various Roadshows (WP9, T3.2) and finally used for the Amsterdam Roadmap (WP4, T2 too). The Amsterdam energy transition roadmap was published in 2018.The essence of the City-zen Urban Energy Transition Methodology is as follows: based on extensive research into energy characteristics of the city, planned near-future developments, stakeholder analyses and future scenarios, a sustainable city vision can be elaborated, after which a roadmap with different energy transition paths can be defined.Such a roadmap was already made for the city of Amsterdam; this report uses maps and images of that study to exemplify steps taken in the City-zen Methodology. ... Read more

The City-zen Roadshow travels with a team of internationally recognized experts, in the field of energy planning and design to help develop a sustainable agenda for cities and their neighbourhoods. The overall aim of the Roadshow team is to work closely with people from the hosting city, whether they be city leaders, energy planners, local architect, professionals, academics, students and citizens. The Roadshow normally spends 5 days in each hosting city (in Amersfoort they were a compressed 3 days) to deliver energy and urban design fun-shops in which all local stakeholders are welcome and encouraged to join and to take ownership of the final outcomes, outcomes that will allow the cities resources, both people and energy, to be directed effectively, by highlighting the energy challenges and potentials to be found in their
neighbourhoods, and to finally present a sustainable ‘City Vision’.

The following report will describe the activities and outcomes of the City-zen Amersfoort Roadshow that took place in the Netherlands from the 16th to the 18th of October 2019. ... Read more

Many cities across the world have the ambition of becoming carbon neutral, but exact figures of progress toward that goal are limited. Regarding Europe’s not overly ambitious 2020 carbon emission targets, many countries still have a long way to go (see Fig. 1), with cities as the prime objects for improvement. It is fair to say that the energy transition is lagging behind, for which several reasons can be given.
One assumption, based on experience with projects with various European cities, is that cities—their administrations and other stakeholders—generally have insufficient understanding of how to gain and maintain control over the complex process of the energy transition with its multiple actors and diverse objectives and responsibilities.
Another suggested reason is the lack of appropriate approaches, strategies, and methods to guide the energy transition in formulating clear targets and intermediate steps of mainly technical and spatial interventions. These, however are currently under development, and are being tested in cities across the continent—such as in Gothenburg, London, Rotterdam, Cologne, and Genova within the EU project Celsius (www.celsiuscity.eu), and in Amsterdam and Grenoble, for the EU project City-zen (www.cityzen-smartcity.eu)—with promising results so far.
The main research question underlying this chapter is: How can cities be supported in their energy transition toward carbon neutrality?
We will describe the development of approaches, strategies, and methods for the urban energy transition, their background and theoretical basis, and present urban case studies where they were applied. Finally, an outlook will be given for methodological developments in the near future. ... Read more

The City-zen Roadshow travels with a team of internationally recognized experts, in the field of energy planning and design to help develop a sustainable agenda for cities and their neighbourhoods. It will visit 9 cities in total over a 5-year period who are seeking expert guidance on how to become more sustainable and wish to move towards energy neutrality. The overall aim of the Roadshow team is to work closely with people from the hosting city, whether they be city leaders, energy planners, local architect, professionals, academics, students and citizens. The Roadshow spends 5 days in each hosting city to deliver energy and urban design fun-shops in which all local stakeholders are welcome and encouraged to join and to take ownership of the final outcomes. Outcomes that will allow the cities recourses, both people and energy, to be directed effectively, by highlighting the energy challenges and potentials to be found in their neighbourhoods, and to finally present a sustainable ‘City Vision’. 
The following report will describe the activities and outcomes of the Roeselare Roadshow that took place in Roeselare (Belgium), between the 23rd & 27th of April 2018. ... Read more

The City-zen Roadshow travels with a team of internationally recognized experts, in the field of energy planning and design to help develop a sustainable agenda for cities and their neighbourhoods. The Roadshow team work closely with people from the hosting city, whether they be city leaders, energy planners, local architect, professionals, academics, students and of course the citizens themselves. The Roadshow typically spends 5 days in each hosting city to deliver energy and urban design workshops in which all local stakeholders are welcome and encouraged to join and to take ownership of the final outcomes. Outcomes that will allow the cities recourses, both people and energy, to be directed effectively, by highlighting the energy challenges and potentials to be found in their neighbourhoods, and to finally present a sustainable ‘City Vision’. The following report will describe the activities and outcomes of the Roadshow (Sustainable Island Menorca ‘Roadshow’) that took place at the Institut Menorquí d'Estudis (IME) in Mahón on the island of Menorca, between the 24th & 28th of April 2017. ... Read more

The City-zen Roadshow travels with a team of internationally recognized experts, in the field of energy planning and design to help develop a sustainable agenda for cities and their neighbourhoods. It will visit 8 cities in total over a 4-year period who are seeking expert guidance on how to become more sustainable and wish to move towards energy neutrality invite the Roadshow. The overall aim of the Roadshow team, known as ‘Roadies’, is to work closely with people from the hosting city, whether they be city leaders, energy planners, local architect, professionals, academics, students and of course the citizens themselves. The Roadshow will spend 5 days in each hosting city to deliver energy and urban design workshops in which all local stakeholders are welcome and encouraged to join and to take ownership of the final outcomes. Outcomes that will allow the cities recourses, both people and energy, to be directed effectively, by highlighting the energy challenges and potentials to be found in their neighbourhoods, and to finally present a sustainable city vision. The following report will describe the activities and outcomes of the Roadshow that took place in Belfast between the 18th & 22nd of January 2016, in specifically in the neighbourhood of Colin (West Belfast). ... Read more