Life-cycle assessment methodology to assess zero emission neighboorhood concept


Buildings represent a critical piece of a low-carbon future and their long lifetime necessitates urgent adoption of state-of-the-art performance standards to avoid significant lock-in risk. So far, life-cycle assessment (LCA) studies have assessed buildings (conventional and Zero Emission Building (ZEB)), mobility and energy systems mainly individually. Yet, these elements are closely linked, and to assess the nexus of housing, mobility, and energy associated with human settlements by aiming for Zero Emission Neighborhoods (ZENs) gives a unique chance to contribute to climate change mitigation. ZEBs and ZENs are likely to be critical components in a future climate change mitigation policy.

This study addresses the challenge of how to use LCA when implementing such a policy, in line also with the introduction of the more stringent Energy Performance of Buildings Directive in 2010 that requires new buildings to be built with nearly ZEB standards by the end of 2020. The specific aims of this report are fourfold. First, to develop and apply an LCA model to support the evaluation of ZEN design concepts with respect to greenhouse gas (GHG) emissions and other potential environmental impacts. Second, to clarify important contributing factors as well as revealing criticalities and sensitivities for GHG emission reductions and environmental performance of such ZEN design concepts. Third, to establish a model basis for other LCA studies on a neighbourhood scale, in terms of a high-quality modelling approach regarding consistency, transparency, and flexibility. Fourth, to apply our model on two cases; a hypothetical case of a neighbourhood consisting of single family house of passive house standard and on Zero Emission Village Bergen (ZVB).

For the first case, the neighbourhood consists of single-family houses built according to the Norwegian passive house standard. We designed four scenarios where we tested the impact of the house sizes, household size, energy used and produced in the buildings, and mobility patterns. Also, we ran our scenarios with different levels of decarbonization of the electricity mix over a time period of 60 years.

Our results show the importance of the operational phases of both building and mobility at year 1, and its decline over time induced by the decarbonization of the electricity mix. In year 60, embodied emissions are then responsible for the majority of the emissions when the electricity mix is decarbonized. The most important contributing factors have been identified as the operational phases of the Building and Mobility subsystems when the carbon intensity of the electricity mix is high, and as the embodied emissions in materials when the carbon intensity of the electricity mix becomes low. A reduction of the following factors has been identified as beneficial for the overall GHG emissions of a ZEN: (1) building floor area by house either/or by inhabitants, (2) passenger cars travel distances by household, which can be achieved by several means; e.g. commuting with public transport and/or by carpooling initiatives, (3) energy use in the buildings, which is reduced by the use of the passive house standard, and (4) carbon intensity of the electricity mix.

The second case – ZVB – consists of residential and non-residential buildings, with a total area of 91 891 m2; 695 dwellings and 1 340 inhabitants. The total emissions associated with the physical elements (buildings, mobility, open spaces, networks and on-site energy) and the life cycle stages (A1-A3, B4 and B6) resulted in a total of 117 kton CO2-eq over the lifetime. This equals 1.5 ton CO2-eq/capita/year and 21.2 kg CO2-eq/m2/year, referring to heated building floor area and as yearly average emissions over the 60 year analysis period. The emissions are distributed between the elements and life cycle stages. Buildings stand for the majority of the total emissions, accounting for about 52% of the total emissions over the lifetime. The mobility is the second most contributing element, responsible for 40% of the total emissions. The emissions from the networks and open spaces constitute only 2.3% together. A sensitivity analysis showed the emission intensity for electricity and the assumption of allocating emissions from waste incineration to the waste management system rather than to district heat to have a considerable impact on the results. If an EU28+NO electricity production mix is used instead of the Norwegian electricity production mix, total emissions over the 60 years analysis period will increase with 12.5%. This is despite the fact that also negative emissions from the on-site electricity production will be larger, due to the significant increase in emissions from electricity consumed in mobility. If the emissions from waste incineration is not allocated to the district heating production, the total emissions are decreased with 25.3%. Hence, this is a most critical assumption in the LCA model.

The most important contributing factors have been identified as the operational phases of the Building and Mobility subsystems when the carbon intensity of the electricity mix is high, and as the embodied emissions in materials when the carbon intensity of the electricity mix becomes low. A reduction of the following factors have been identified as beneficial for the overall GHG emissions of a ZEN: (1) building floor area by house or by inhabitants, (2) passenger cars travel distances by household, which can be achieved by several means; e.g. commuting with public transport and/or by carpooling initiatives, (3) energy use in the buildings, which is reduced by the use of the passive house standard, and (4) carbon intensity of the electricity mix.

Introducing passive house standards on buildings has the potential to drastically decrease the overall CO2-eq emissions of a ZEB, but also of a ZEN; up to by 191% when assuming an average European electricity mix. Yet, by using a highly decarbonized electricity mix, such as is the case in Norway, the decrease is much lower, around 12%.

Also, we found the choice of the functional unit to be decisive for the conclusion of the study. When conducting LCAs on a neighbourhood scale, we thus argue for the use of a primary functional unit “per neighbourhood”, and a second “per person”. The use of a “per m2 floor area” unit is misleading as it does not give credits for reducing the total built floor area.

All these findings demonstrate that the model is capable of long-term analyses of both homogenous and complex neighbourhoods, and provides a detailed understanding of possible future development of the different elements of the neighbourhood and their GHG emissions.

This report is a part of FME ZEN Work Package 1 Analytic framework for design and planning of zero emission neighbourhoods (ZEN). The goal for WP 1 is to develop definitions, targets and benchmarking for ZEN, based on customized indicators and quantitative and qualitative data. Additionally, an LCA methodology for energy and emissions at neighbourhood scale is developed, as well as a citizen-centred architectural and urban toolbox for design and planning of ZEN.

Exploring the pathway from zero-energy to zero-emission building solutions: A case study of a Norwegian office building


This paper explores the most influential aspects regarding the environmental and economic performance of zero-energy and zero-emission buildings and proposes a pathway for transition in building solutions. A representative zero-energy office building in Norway is investigated with alternative design solutions to achieve zero-emission status i.e., the extensive use of locally generated energy through photovoltaic (PV) panels and the use of materials with low embodied emissions, such as low-carbon concrete and wood. A life cycle environmental and economic assessment is performed to evaluate specific indicators during the building life cycle: cumulative energy (CED), global warming potential (GWP), and equivalent annual cost (EAC).

The extensive use of PV panels was most effective in lowering the operational energy because it reduced the CED by about 30% compared to the building as-built. However, the extensive use of wood in the construction contributed the most to GWP reduction, with around 30% decrease compared to the building as-built. Finally, the differences in EAC were interestingly insignificant among the alternatives, with the investment costs dominating the EAC for all designs examined.

The findings of this paper emphasise that a full compensation of the life cycle GHG emissions from materials is difficult to achieve through renewable energy, even with extensive use of PV panels, especially in a low-carbon grid situation as in Norway. A pathway strategy from zero-energy towards zero-emission buildings must therefore strongly focus on the materials’ embodied energy and emissions because low operational energy demand is already a regulatory priority in most countries.

Aesthetic Preference as Starting Point for Citizen Dialogues on Urban Design: Stories from Hammarkullen, Gothenburg


This article sets out to describe the role of aesthetics in citizen dialogues during the upgrading of a local swimming pool in Hammarkullen, Gothenburg. The swimming pool became an important project because of its role in a larger neighbourhood renovation project that allowed the municipality to focus on citizen engagement and inclusion. The engagement process showed the importance of the local swimming pool for a marginalized group of women of Somali origin, and a decision was made to keep the swimming pool instead of demolishing it. This led to collaboration between project coordinators, the Public Art Agency, an artist and an architect. Individual qualitative interviews focusing on storytelling were undertaken with key stakeholders.

The findings show that aesthetic quality mediated the communicative processes between project coordinators and citizens. Art in public space is more than just aesthetics or something to look at; art provokes a wide variety of responses and artists use a variety of means to engage with their public and creating dialogue. Yet the project managers failed to consider the creative process of the architect and her perspective on aesthetic quality and building functionality.

Stakeholders take different stances to whether aesthetic quality can be a way of grounding, communicating and evolving, or whether it is a matter of beauty where the artist or architect takes the lead. While the project coordinators affirm sameness, different understandings of aesthetic quality actively negotiate social differences. Inability to consider creative practices’ work processes in relation to citizen dialogue can result in conflicts between art, architecture and governance during the transformation of a neighbourhood.

Predictive rule-based control to activate the energy flexibility of Norwegian residential buildings: Case of an air-source heat pump and direct electric heating


The building energy flexibility potential of a Norwegian single-family detached house is investigated using predictive rule-based control (PRBC) and building performance simulation (using IDA ICE). Norwegian timber buildings are lightweight and four different insulation levels are considered. Both on-off and modulating air-source heat pumps are analyzed and compared to direct electric heating which is the most common heating system for Norwegian residential buildings. A detailed model for both the heat pump system and the building is implemented, a level of detail not found in previous research on building energy flexibility.

The three PRBC investigated have the following objectives: reduce energy costs for heating, reduce annual CO2eq. emissions and reduce energy use for heating during peak hours. This last objective is probably the most strategic in the Norwegian context where cheap electricity is mainly produced by hydropower. The results show that the price-based control does not generate cost savings because lower electricity prices are outweighed by the increase in electricity use for heating. The implemented price-based control would create cost savings in electricity markets with higher daily fluctuations in electricity prices, such as Denmark. For the same reasons, the carbon-based control cannot reduce the yearly CO2eq. emissions due to limited daily fluctuations in the average CO2eq. intensity of the Norwegian electricity mix. On the contrary, the PRBC that reduces the energy use for heating during peak hours turns out to be very efficient, especially for direct electric heating. For air-source heat pumps, the control of the heat pump system is complex and reduces the performance of the three PRBC.

Therefore, results suggest that a heat pump system should be modeled with enough detail for a proper assessment of the building energy flexibility. First, by varying temperature set-points there is a clear interaction between the prioritization of domestic hot water and the control of auxiliary heaters which increases energy use significantly. Second, the hysteresis of the heat pump control and the minimum cycle duration prevent the heat pump from stopping immediately after the PRBC requires it. Finally, the paper shows that the influence of thermal zoning, investigated here by cold bedrooms with closed doors, has a limited impact on the building energy flexibility potential and the risk of opening bedroom windows.

Impacts of future weather data typology on building energy performance – Investigating long-term patterns of climate change and extreme weather conditions

Future weather files for a robust design of buildings and neighborhoods against climate change

In the last decade, some of the warmest years on record have been experienced. Failure in climate change adaptation can lead to costly short- and long-term issues, such as blackouts due to energy supply disruption. These problems partly are arising from the fact that existing buildings are not designed for atypical conditions, and their expected performance is based on most-likely conditions. Building performance simulation (BPS) empowers designers to evaluate a proposed design under the probable climate conditions that a building will face during its lifetime. This work aims at answering the question: what type of future weather files enable building engineers and designers to more reliably test robustness of their designs against climate change.
Extreme weather files are needed for a robust design in building and urban scales

The standardized weather files of today are a single-year of typical weather data that represent typical regional climate conditions based on historical data. One of the main disadvantages of this method on climate change impact assessment is its averaging nature. The averaging process can result in missing extreme values and therefore shows how systems designed taking into consideration only typical conditions could quickly become a costly mistake (due to under-dimensioning).
This study provides an overview of the major approaches for creating future weather data sets. For the first time, the effects of using major available approaches for generating future weather files are studied on the calculation of energy performance of buildings. The building models were simulated in isolation and combined to create a virtual neighborhood.

The study investigates the possibility and importance of using extreme weather years in BPS at both the building and neighborhood scales. This will allow understanding the magnitude of the risk induced at large scale by not taking into account possible future climate extremes.

The analysis of the virtual neighborhood revealed that the peak electric power demand for the neighborhood can increase up to 16.8% under extreme conditions in comparison to the typical conditions. These results underline the importance of considering extreme conditions in studying the impacts of climate change on larger spatial scales (e.g. urban and city scales) and preparing urban energy systems for such future conditions.

In conclusion, our work provided further evidence that proper weather data sets based on high resolution data from climate models and several climate scenarios, including extreme conditions, are required to empower building engineers and architects to test their design solutions under future climate uncertainties.

By Amin Moazamia

Public private collaboration in a zero emission context

This aim of study connected to this report is to answer the following research question: «What are the key drivers of success and failure when it comes to public private collaboration in a zero-emission context?» In this regard, a narrative literature review is conducted to find relevant scientific articles and cases. The cases are studied and results are obtained. Results show various success factors and barriers in public private collaboration in the context of zero emission neighborhood. The results are presented.

Anandasivakumar Ekambaram

Responsive building envelope concepts in zero emission neighborhoods and smart cities – A roadmap to implementation


Designing a zero emission neighborhood (ZEN) from an energy point of view, has the benefit of distributing loads over time by creating a mosaic of buildings which individually may not have a zero emission balance, but reach it as an ensemble. Responsive building envelopes (RBEs) are expected to play an important role in the design of ZENs and future smart sustainable cities. RBEs are useful to optimize the balance between several energy flows at single- and multi building scale, as well as to actively manage both on-site renewable- and purchased energy in addition to improving user experience and indoor comfort by providing an interactive interface with the outdoors.

This article provides a review of the potential and the requirements associated with using RBEs to manage complex interactions between buildings, clusters of buildings and utility grids. A six-step pathway for the implementation of RBEs in ZEN-like projects are proposed. The six steps are related to identifying; purpose of response, scale and interdependency, functionality, trigger and control, interactions and finally to identifying technical solutions. The proposed process emphasizes the importance of defining specific information such as the responsive goal hierarchies, the scale of the responses in relation to their purpose, and the importance of the aesthetic expression to foster positive user experience.


ZEN pilot projects: Mapping of the pilot projects within the Research Centre on Zero Emission Neighbourhoods in Smart Cities


This report on the pilot projects of the Research Centre on Zero Emission Neighbourhoods in Smart Cities will give the reader an overview of eight pilot projects of the Centre, focusing on the challenges to develop or transform the pilot areas into Zero Emission Neighbourhoods.

The objective of the ZEN Centre is to develop products and solutions that will lead to the realization of sustainable neighbourhoods with zero greenhouse gas emissions. These solutions will be tested in the eight real life pilot projects in Norwegian municipalities. When searching for the best solutions, we first need to map the pilot projects and the challenges they are facing on the way to become sustainable zero emission neighbourhoods. This report will therefore serve as an introduction to the eight pilot projects to help the ZEN partners to develop an understanding for the pilot projects and their challenges, as a base for further research and cooperation.

This report will start with a short introduction of the Research Centre and present a working definition for a Zero Emission Neighbourhood. Each of the eight pilot projects are described in detail by their individual characteristics regarding location, stakeholders, goals, measures, status of project development, and challenges. Challenges were identified through qualitative interviews with stakeholders of the pilot projects. These interviews were conducted in 2017.

A systematic documentation of the process and challenges to develop ZENs will help to identify the success factors and best practices that are needed for planning and developing ZENs. This enables the involved partners to learn from the first pilot projects, and to transfer solutions to other neighbourhood developments. This report provides a foundation for further follow-up, documentation, and analysis.


Norwegian Summary

Denne rapporten vil gi leseren en oversikt over de åtte pilotprosjektene i ZEN Forskningssenter, med fokus på utfordringene som ligger i å utvikle og transformere pilotprosjektene til nullutslippsområder.

Målet med forskningssenteret ZEN er å utvikle produkter og løsninger som vil føre til realisering av bærekraftige nabolag med null klimagassutslipp. Disse løsningene blir testet i åtte pilotprosjekter i norske kommuner. Når vi søker etter de beste løsningene, er det viktig å ha kartlagt pilotprosjektene med tanke på de utfordringene de står overfor med tanke på å oppnå bærekraftige nabolag med null utslipp av klimagasser. Denne rapporten vil derfor fungere som en introduksjon til de åtte pilotprosjektene og skal hjelpe ZEN-partnerne til å utvikle en felles forståelse for pilotprosjektene og deres utfordringer som grunnlag for videre forskning og samarbeid.

Rapporten starter med en kort introduksjon av forskningssenteret og en arbeidsdefinisjon av hva som legges i ZEN. Hvert av de åtte pilotprosjektene er beskrevet i detalj med deres individuelle egenskaper som plassering, interessenter, mål, tiltak, status for prosjektutvikling og utfordringer. Utfordringene ble identifisert gjennom kvalitative intervjuer med de involverte aktørene i pilotprosjektene, mange av dem er ZEN partnere. Disse intervjuene ble gjennomført i 2017.

En systematisk dokumentasjon av prosessen og utfordringene med å utvikle ZENs vil bidra til å identifisere suksessfaktorer og beste praksis for å planlegge og utvikle ZEN. Dette gjør det mulig for de involverte partnerne å lære fra de første pilotprosjektene og overføre løsninger til andre byutviklingsprosjekt senere. Denne rapporten danner grunnlaget for videre oppfølging, dokumentasjon og analyse.

Possibilities for supplying Norwegian apartment blocks with 4th generation district heating


This report is a part of Work Package 4 Energy Flexible Neighbourhoods. The goal for WP 4 is to develop knowledge, technologies and solutions for design and operation of energy flexible neighbourhoods.

4th generation district heating is evaluated as a sustainable solution for covering the heating demand in Zero Emission Neighbourhoods and reducing the strain on the electricity grid. There are, however, some technical challenges that must be solved before it is introduced. One of them is to determine how low the supply temperature could be in different building types, which again will determine the minimum district heating supply temperature. This report is evaluating the minimum supply temperature in Norwegian apartment blocks based on effects of improving the thermal envelope and reducing the temperature levels for the heating system. The analysis is based on building simulation and focuses on whether the reduced supply temperature guarantees the comfort in the building, considering the coldest room with a heating setpoint of 22 °C and a minimum acceptable indoor temperature of 19,0 °C.

The simulated buildings are based on the data available from the IEE project Tabula. Generic models representative for Norwegian apartment blocks have been developed in IDA ICE. They consist of eight age classes and three levels of energy performance: • Prior to 1956, from 1956-1970, 1971-1980, 1981-1990, 1991-2000, 2001-2010, 2011-2020 and 2020 →. • Original, intermediate renovation and standard renovation For the intermediate renovation level, it is only the windows and infiltration rates that have been changed. Tabula also includes an ambitious renovation, but this has not been modelled as the results are expected to be similar to those for the newest age class. Simulations are performed with two different dimensioning temperature levels for the radiators typical for Norwegian buildings; 80/60 and 60/40 °C. The results showed that it is possible to reduce the supply temperature to the radiators from 80 to 60 °C for buildings from 1971-80 and all newer age classes, even for the non-renovated buildings. This is based on a minimum acceptable indoor temperature of 19.0 °C (according to the Norwegian building regulations, TEK). For the older age classes, an acceptable indoor temperature is not achieved for the non-renovated buildings when reducing the supply temperature. Although it is sufficient to perform the intermediate renovation to maintain temperatures above 19 °C, it is highly recommended to perform the standard renovation for these age classes to reduce the number of hours with a significantly reduced indoor temperature compared to the setpoint temperature. In addition to reduce the heating demand and thus lead to energy savings, this will also ensure that the occupants are satisfied with their thermal environment. It is important to note that the conclusions would be different if the minimum acceptable temperature was set higher, for instance at 20 or 21 °C. The results can be used by district heating companies, building owners, contractors and consulting companies in order to evaluate the introduction of 4th generation district heating in Norwegian apartment blocks. Both the models and excel sheets with hourly results are available for partners and researchers within FME ZEN.

Linear optimization of district heating systems: Description of an upgraded district heating module for eTransport


eTransport is a linear optimization tool for evaluating energy supply alternatives for building areas. This report describes an improved, more realistic district heating (DH) module that has been developed for eTransport. The new module includes several improvements as compared to the previous module:

  • Varying mass flow that depends on the heat load, as opposed to constant mass flow. 
  • Pressure included as a variable, with certain limits for minimum pressure and minimum pressure drop at the loads. 
  • Calculation of pumping power is included in the module, and pumping power due to pressure losses in pipes and at loads is included in the objective function 
  • A more realistic calculation of heat losses included, and the heat losses are included in the heat load 
  • The module allows supply flow to both directions in a pipe; a property which is relevant when more heat sources are present in a DH grid. This feature is however yet to be tested properly.

The report presents the main equations required for mathematical description of a district heating system are presented, followed by the approach taken for linear representation of these equations, required for eTransport. The report includes a brief evaluation of the module using a simple test network, and discusses the simplifications and limitations of the present module, giving suggestions for further improvements.


Fjernvarme er en viktig muliggjørende teknologi i det grønne skiftet. Fjernvarme kan nyttiggjøre energi som ellers ville gått til spille, slik som gjenvunnet varme fra avfallsforbrenning og industriprosesser; eller mindre spillvarmekilder tilgjengelig i byer, slik som datasentre og store matvarebutikker. Ved hjelp av et fjernvarmesystem kan slike kilder anvendes til oppvarming av boliger og næringsbygg. Med et godt samspill med kraftnettet bidrar fjernvarme i tettbygde strøk til å avlaste kraftnettet og tilgjengeliggjøring elektrisitet til andre formål enn til oppvarming. Bygging av et fjernvarmesystem krever store investeringer i startfasen, og dermed er det viktig å vite hvilke energikilder man bør velge til et gitt område for å minimere tilbakebetalingstiden. Det er derfor vanlig å bruke planleggingsverktøy for sammenlikning av ulike energiforsyningsalternativer til området. eTransport er et slikt verktøy, lagd av SINTEF Energi i 2006. Verktøyet skal oppgraderes og videreutvikles i FME ZEN. eTransport omfatter flere energibærere, og finner den optimale måten til å drifte energisystemet, samt en optimal ekspansjonsplan i et geografisk definert område. I mange tilfeller vil det være konkurransen mellom ulike energibærere: behovet for oppvarming kan dekkes av elektrisitet eller av et fjernvarmesystem og varme kan genereres fra kilder. eTransport beregner de årlige driftskostnadene for ulike energisystemdesign, og sender disse til en investeringsmodell som finner en optimal ekspansjonsplan.

Denne rapporten beskriver en oppgradering av fjernvarmemodulen i eTransport. I den tidligere versjonen av eTransport var modulen for beskrivelse av et fjernvarmesystem svært forenklet. Den oppgraderte modulen er mer realistisk i forhold til beregning av massestrøm, varmetap, trykktap og pumpearbeid. Modulen tillater dessuten forsyning av varme i begge retninger i et rør, noe som kan være aktuelt i et varmenett som utnytter flere, distribuerte varmekilder. eTransport et lineært optimalisverktøy, og rapporten presenterer den valgte tilnærmingen for lineær formulering av de viktigste likningene for beskrivelse av et fjernvarmesystem.

A Zero Emission Neighbourhoods Data Management Architecture for Smart City Scenarios: Discussions toward 6Vs challenges


A huge volume of data are being generated from multiple sources, including smart cities, the IoT devices, scientific modeling, or different big data simulations; but also from users’ daily activities. These daily new data are added to historical repositories, providing the huge and complex universe of the digital data. Recently, the Fog-to-Cloud (F2C) data management architecture is envisioned to handle all big data complexities, from IoT devices (the closest layer to the users) to cloud technologies (the farthest layer to the IoT devices), as well as different data phases from creation to usage from fog to cloud scenario. Moreover, the F2C data management architecture can have several benefits from the combined advantages of fog (distributed) and cloud (centralized) technologies including reducing network traffic, reducing latencies drastically while improving security.
In this paper, we have several novel contributions. First, we described the previous studies of the Zero Emission Buildings (ZEB) in the context of the data flow and movement architecture. Second, we have proposed Zero Emission Neighbourhoods (ZEN) data management architecture for smart city scenarios based on a distributed hierarchical F2C data management. Indeed, we used the 6Vs big data challenges (Volume, Variety, Velocity, Variability, Veracity, and Value) for evaluating the data management architectures (including ZEB and ZEN). The result of the evaluation shows that our proposed ZEN data management architecture can address 6Vs challenges and is able to manage the data lifecycle from its production up to its usage.

Future Trends in District Heating Development

Purpose of Review

This article describes challenges that should be overcome towards implementation of low-temperature district heating (LTDH). The trends in development, operational issues, and legislative framework were revised.

Recent Findings

The new substation design with solutions to avoid legionella bacteria issue, improved network topology and control strategies, opportunities of LTDH for buildings under various renovation stages and construction year were identified as the most crucial for the transition to 4th generation district heating (DH). Importance of heat load aggregation to avoid peak load issue in the areas with low-energy buildings (LEB) and solutions for transition from high temperature to low temperatures in the DH network have been shown


The findings indicate that there is a huge potential for achieving low-carbon society and improvement in energy efficiency under transition to LTDH. The solutions for transition from high-temperature DH to LTDH exist; however, they need good policies and market availability to be implemented.

From Zero Emission Buildings (ZEB) to Zero Emission Neighbourhoods (ZEN): A Mapping Review of Algorithm-Based LCA


The building industry is responsible for approximately 40% of energy consumption and 36% of greenhouse gas emissions in the European Union (EU). The most efficient way of reducing a building’s environmental impact is addressing it in the design stage. Here, design freedom is the greatest, but uncertainty is high and there is a nearly limitless number of design options.

Based on experiences with zero emission buildings (ZEB) and zero emission neighbourhoods (ZEN), a mapping review has been conducted to analyse how parametric life cycle assessment (LCA) and algorithms have been used to address neighbourhoods, buildings, and construction materials. Results have identified a general gap of knowledge regarding the use of parametric LCA models for decision-support purposes, demonstrated by the substantial focus on analytical methods compared to procedural methods. Implications for the evolution from ZEB to ZEN are twofold: (i) an integrated approach with multiple tools and methods is required, and (ii) further development of algorithms in the tool are needed to address complexity, sensitivity, and uncertainty.

This study is expected to foster the development of algorithmic approaches to improve the ZEB tool as a decision-support tool. Further research should address the key questions of when and how

Analysing methodological choices in calculations of embodied energy and GHG emissions from buildings


The importance of embodied energy and embodied greenhouse gas emissions (EEG) from buildings is gaining increased interest within building sector initiatives and on a regulatory level. In spite of recent harmonisation efforts, reported results of EEG from building case studies display large variations in numerical results due to variations in the chosen indicators, data sources and both temporal and physical boundaries.

The aim of this paper is to add value to existing EEG research knowledge by systematically explaining and analysing the methodological implications of the quantitative results obtained, thus providing a framework for reinterpretation and more effective comparison. The collection of over 80 international case studies developed within the International Energy Agency’s EBC Annex 57 research programme is used as the quantitative foundation to present a comprehensive analysis of the multiple interacting methodological parameters. The analysis of methodological parameters is structured by the stepwise methodological choices made in the building EEG assessment practice. Each of six assessment process steps involves one or more methodological choices relevant to the EEG results, and the combination potentials between these many parameters signifies a multitude of ways in which the outcome of EEG studies are affected.

Design and construction strategies for reducing embodied impacts from buildings – Case study analysis


The dominance of operational energy and related greenhouse gas (GHG) emissions of most existing buildings is decreasing in new construction, when primary fossil energy of building operation decreases as result of the implementation of energy efficiency measures as well as a decarbonisation of national energy mixes. Stakeholders therefore have a growing interest in understanding the possibilities for reducing embodied impacts in buildings. In the IEA EBC project ‘Annex 57’ a broad call for case studies was launched with the aim to identify design strategies for reducing embodied energy and GHG emissions (EEG) from buildings.

The aim of this paper is to identify and provide a collected and comprehensive overview of quantitative reduction potentials of the particular EEG reduction strategies which should be considered by the stakeholders engaged in, and with the capacity to influence the outcome of, individual building projects. This is done by a systematic analysis of the Annex 57 case study collection as well as additional scientific literature. While it should be noted that the actual EEG savings at building level illustrated in this collection of studies are only applicable to each specific case, importantly this multiple cross-case analysis has provided rigorous evidence of the considerable potential to reduce embodied impacts in the design and construction of new and refurbished buildings.

Domestication, acceptance and zero emission ambitions: Insights from a mixed method, experimental research design in a Norwegian Living Lab


The Trondheim Living Lab is a detached single-family zero emission building (ZEB) that is planned to reach a zero-emission balance over the course of its estimated 60-year lifetime. This is achieved by a broad variety of technical strategies such as passive and active energy design and efficient installations, as well as calculations of embodied emissions. In qualitative experiments conducted between September 2015 and April 2016 six different groups lived in the house for 25 days each. Based on direct observation (mainly through sensors registering temperature, humidity, CO2 levels and energy use), participant observation and interviews before, during and after the stay, the paper analyses the unfolding domestication of the building along three dimensions; practical, symbolic and cognitive.

The paper provides an account of which expected or unexpected occupant actions matter in which way for the zero emission ambitions of the building. Moreover, by studying the way in which the six groups within the three different categories student, family and elderly experienced living in this demonstration building this paper contributes a more detailed understanding of the overall acceptance of a ZEB in Norway.

Is a net life cycle balance for energy and materials achievable for a zero emission single-family building in Norway?


In this study, the objective is to redesign a previous concept for a single-family Zero greenhouse gas Emission Building (ZEB). The concept is redesigned based on comparing greenhouse gas (GHG) emission loads and compensation from different design solutions applied in Norwegian single-family ZEB pilot buildings and selected sensitivity studies. The objective is to see if a previously developed ZEB model (2011) can be redesigned to achieve a life cycle energy and material emission balance (ZEB-OM), which previously was not achieved.

Five different design parameters are evaluated: area efficiency, embodied emissions in the envelope, insulation thickness, heating systems and different roof forms with respect to the photovoltaic area. Embodied emissions reductions were possible in the ground foundation, from around 1 kg CO2/m2 to 0.6 kg CO2/m2 per year. Both models are able to compensate for all operational emissions. The new model is in addition able to compensate for 60% of embodied emissions, whereas the previous model only could compensate for 5%. The new model does not reach the life cycle energy and material balance. The paper presents and discusses different approaches for achieving the ZEB-OM balance. Further concept model optimization is needed.

Characterizing the energy flexibility of buildings and districts


The large penetration rate of renewable energy sources leads to challenges in planning and controlling the energy production, transmission, and distribution in power systems. A potential solution is found in a paradigm shift from traditional supply control to demand control. To address such changes, a first step lays in a formal and robust characterization of the energy flexibility on the demand side. The most common way to characterize the energy flexibility is by considering it as a static function at every time instant. The validity of this approach is questionable because energy-based systems are never at steady-state. Therefore, in this paper, a novel methodology to characterize the energy flexibility as a dynamic function is proposed, which is titled as the Flexibility Function.

The Flexibility Function brings new possibilities for enabling the grid operators or other operators to control the demand through the use of penalty signals (e.g., price, CO2, etc.). For instance, CO2-based controllers can be used to accelerate the transition to a fossil-free society. Contrary to previous static approaches to quantify Energy Flexibility, the dynamic nature of the Flexibility Function enables a Flexibility Index, which describes to which extent a building is able to respond to the grid’s need for flexibility. In order to validate the proposed methodologies, a case study is presented, demonstrating how different Flexibility Functions enable the utilization of the flexibility in different types of buildings, which are integrated with renewable energies.

Real Time Measurement of Dynamic Metabolic Factor (D-MET)


The presented study describes developing a method for observing building occupants’ activity. Once their activity is registered, such data can be used to identify typical patterns in their behaviour. The collected information will support development of an occupant-behaviour-energy-related model in residential buildings. Data registration was done with the use of the Microsoft Kinect device as a depth registration camera. This research explores an innovative approach to investigating residents’ living and working habits. It supports the already existing thermal comfort models by delivering high resolution information about occupants’ activities. The obtained solution and its output will be used in the next stage of developing a dynamic metabolic rate (D-MET) model that will simulate the MET value. With proper data, it will be possible to estimate the real impact of occupants and their behaviour on energy consumption of buildings.

Sensing and Data Acquisition


Occupant sensing and data acquisition are essential elements for occupant behavior research. A wide range of different types of sensors has been implemented to collect rich information on occupants and their interactions with the built environment, such as presence, actions, power consumption, etc. This information establishes a foundation to study the physiological, psychological, and social aspects of occupant behavior. This chapter summarizes existing occupancy and occupant behavior sensing and data acquisition technologies in terms of field applications, and develops nine performance metrics for their evaluation. The reviewed technologies focus on both occupants’ presence and interactions with the built environment, and are grouped into six major categories: image-based, threshold and mechanical, motion sensing, radio-based, human-in-the-loop, and consumption sensing. This chapter provides an overview and discussion of different current state-of-the-art and future sensing technologies for researchers.

Towards Zero Emission Neighbourhoods: Implications for the Power System


This paper investigates the development of neighbourhoods with ambitious emission targets in the Nordic countries and their value for the power system. The targets relate to compensating for emissions in neighbourhoods through local low-carbon electricity and heat production. The first part of our analysis investigates local generation expansion with a neighbourhood perspective using a mixed integer linear programming model. The second part investigates the value of representative neighbourhoods with a country perspective using a generation and transmission capacity expansion model. When coupling the models, results indicate that neighbourhoods with co-generation of electricity and heat are most attractive for the power system in the Nordics, while neighbourhoods with solar PV provide most emission reduction.

Zero emission neighbourhoods in smart cities: Definition, key performance indicators and assessment criteria: version 1.0. Bilingual version.

This document outlines the definition, key performance indicators (KPI) and assessment criteria for the Research Centre on Zero Emission Neighbourhoods in Smart Cities (ZEN research centre). This first version of the ZEN definition includes contributions from the ZEN partners. In total, around 50 people involved in the ZEN research centre have contributed to this document.


Denne rapporten beskriver definisjonen, nøkkelindikatorer og vurderingskriterier som benyttes i forskningssenteret for nullutslippsområde i smarte byer (ZEN senteret). Dette er den første utgaven og inkluderer innspill og bidrag fra ZEN partnerne. Til sammen har omkring femti eksperter fra ZEN senteret bidratt til dette dokumentet. Rapporten foreligger både på engelsk og norsk.

M. K. Wiik, S. M. Fufa, J. Krogstie, D. Ahlers, A. Wyckmans, P. Driscoll, H. Brattebø, A. Gustavsen

Software tools for local energy system operation and expansion


This report describes existing software tools for analysing operation and expansion of local energy systems and is written in WP5 in the Research Centre on Zero Emission Neighbourhoods in Smart Cities (ZEN). WP5 in FME ZEN aims to develop and apply methodologies that identify the socioeconomic optimal operation and expansion of energy systems within demarked areas. The eTransport model is planned to be further developed and used to analyse pilot cases in ZEN. This report provides a brief description of the eTransport model and other alternative models found in the literature or used by partners in FME ZEN. The models are assessed based on their suitability to address the planned research tasks in FEM ZEN WP5. The report also includes a description of models developed for global and international analysis.

We are grateful for views and suggestions provided by Henrik Madsen (professor at DTU), and for comments provided by Anne Grete Hestnes (professor NTNU)

M. L. Kolstad, S. Backe, O. Wolfgang, I. Sartori

Kriterier for pilotprosjekter i ZEN

Dette dokumentet inneholder forslag til kriterier for hva som skal være krav og retningslinjer, samt roller og ansvar knyttet til å være et pilotprosjekt i forskingssenteret Zero Emission Neighbourhoods.

Inger Andresen

Kriterier for case-prosjekter i ZEN

Dette dokumentet inneholder forslag til kriterier for hva som skal være krav og retningslinjer, samt roller og ansvar knyttet til å være et CASE-prosjekt i forskingssenteret Zero Emission Neighbourhoods.

Inger Andresen

Smart EV charging systems for zero emission neighbourhoods


The increased use of electric vehicles (EVs) calls for new and innovative solutions for charging infrastructure. At the same time, it is desirable to improve the energy flexibility of neighbourhoods. This paper presents state-of-the-art for smart EV charging systems, with focus on Norway.

The aim of the study is to start investigating how smart EV charging systems can improve the energy flexibility in a Zero Emission Neighbourhood (ZEN). The intention is that the study will be useful when evaluating activities and technologies for the ZEN pilot areas.

The paper presents energy demand for EV charging and typical charging profiles. Further, it describes how charging stations can interact also with the energy need in buildings and neighbourhoods, local energy production and local electric and thermal energy storage. Examples of commercial smart EV charging systems are described.

The report lists some opportunities for testing smart EV charging in the ZEN pilot areas. Piloting of new technologies and solutions can provide more knowledge about smart EV charging systems, and how they can participate in matching energy loads in buildings and infrastructure with local electricity generation and energy storage.

Åse Lekang Sørensen, Shanshan Jiang, Bendik Nybakk Torsæter, Steve Völler

Recommendations for further developments in eTransport

This memo summarizes promising possibilities for the further development of eTransport, of which some are included in the ZEN work plan 2018-2019. Among other things, the described developments deal with technologies within the energy supply chains for electricity and heat, with the representation of end-users, and with the representation of fluctuations in the availability of local energy sources.

O. Wolfgang, I. Petersen, M. Lorentzen Kolstad, K. Husevåg Kvalsvik

Personal heating and cooling devices: increasing users’ thermal satisfaction


This report is a part of Work Package 3 Responsive and Energy Efficient buildings. The goal for WP 3 is to create cost effective, responsive, resource and energy efficient buildings by developing low carbon technologies and construction systems based on lifecycle design strategies.

As conventional HVAC systems can only make most users satisfied with their thermal environment, there has recently been a lot of research into personal climatization systems. The aim of this literature study was to investigate whether personal heating and cooling solutions could contribute to make all users satisfied with their thermal environment. Potential energy savings are considered a bonus, but was also included in the evaluation of the literature on the subject.

Almost all of the articles reviewed in this report found that the personal climatization devices significantly improved thermal sensation and thermal comfort for the users. For both heating and cooling it was found that combining personal comfort devices resulted in higher comfort improvement and higher energy saving potential. The devices also made it possible to achieve thermal comfort outside the traditional heating and cooling setpoints, thus making it possible to extend the thermal dead-band of buildings, which could lead to substantial energy savings. There are however still some aspects of personal climatization systems where there is suggested further research, and these personal climatization systems are still not commercially available.

Øystein Rønneseth

Thermal energy systems in ZEN

This report reviews the state-of-the-art on thermal energy systems for neighbourhoods. Its main focus is on technologies related to 4th generation district heating (4GDH), biomass combined heat and power (CHP) systems, ground source heat pumps (GSHP) and seasonal heat storage.

Harald Taxt Walnum, Eyvind Fredriksen

Neighbourhood building stock model for long-term dynamic analyses of energy demand and GHG emissions

How should sustainable neighbourhoods be designed to reduce greenhouse gas emissions towards zero? What kind of information do decision makers need to make solid future plans on the neighbourhood level? A dynamic building stock model has been developed for energy- and GHG-emission scenario analyses of neighbourhoods. The model is generic and flexible and can be used to model any neighbourhood where building stock data is available.

Jan Sandstad Næss, Nina Holck Sandberg, Natasa Nord, Magnus Inderberg Vestrum, Carine Lausselet, Aleksandra Woszczek, Øystein Rønneseth, Helge Brattebø

European power market analyses to be carried out within FME ZEN

This report presents a plan for the European power market studies to be carried out within the ZEN Research Centre.

Local energy solutions such as the utilization of local renewable energy resources, and increased energy efficiency, are important for being able to reduce European greenhouse gas emissions to amounts that are in line e.g. with a 2 degree global warming. In the long run, emission levels are affected by many factors including energy system operations, investment decisions, policy instruments, social acceptance for environmental policy, amongst others. Thus, it is not trivial to calculate the full impacts of e.g. 1 TWh extra renewable energy produced locally. Still, it is possible to elaborate on and reveal important mechanisms, which will increase our understanding of those. This report present a plan for European power market studies to be carried out within the FME ZEN. The overall intention with the planned studies is not to provide more accurate numerical calculations than in previous studies, but rather to show how numerical results are affected by which economic mechanisms that are included in such studies. Thus, the studies shall be a basis for creating increased mutual understanding of arguments within FME ZEN.

Ove Wolfgang