A data framework for measuring the energy consumption of the non-domestic building stock

The transition to a low-carbon economy urgently demands better information on the drivers of energy consumption. UK government policy has prioritized energy efficiency in the built stock as a means of carbon reduction, but the sector is historically information poor, particularly the non-domestic building stock. This paper presents the results of a pilot study that investigated whether and how property and energy consumption data might be combined for non-domestic energy analysis. These data were combined in a ‘Non-Domestic Energy Efficiency Database’ to describe the location and physical attributes of each property and its energy consumption. The aim was to support the generation of a range of energy-efficiency statistics for the industrial, commercial and institutional sectors of the non-domestic building stock, and to provide robust evidence for national energy-efficiency and carbon-reduction policy development and monitoring. The work has brought together non-domestic energy data, property data and mapping in a ‘data framework’ for the first time. The results show what is possible when these data are integrated and the associated difficulties. A data framework offers the potential to inform energy-efficiency policy formation and to support its monitoring at a level of detail not previously possible.

Le passage à une économie bas carbone exige de toute urgence de meilleures informations sur les facteurs de consommation énergétique. La politique du gouvernement britannique a donné la priorité à l'efficacité énergétique du parc bâti en tant que moyen de réduction du carbone, mais ce secteur est historiquement pauvre en informations, s'agissant en particulier du parc bâti non résidentiel. Cet article présente les résultats d'une étude pilote qui a étudié si et comment les données relatives à l'immobilier et à la consommation énergétique pouvaient être combinées afin d'analyser la consommation d'énergie non résidentielle. Ces données ont été combinées en une « Base de Données de l'Efficacité Energétique Non Résidentielle », de façon à décrire l'emplacement et les attributs physiques de chaque bien immobilier et sa consommation d'énergie. Le but était d'appuyer la création d'un éventail de statistiques sur l'efficacité énergétique concernant les secteurs industriels, commerciaux et institutionnels du parc bâti non résidentiel, et de fournir des éléments probants solides pour le développement et le suivi d'une politique nationale d'efficacité énergétique et de réduction du carbone. Ces travaux ont rassemblé pour la première fois sous forme d'un « cadre de référence » des données sur l'énergie non résidentielle, des données sur l'immobilier et un mappage de ces données. Les résultats montrent ce qu'il est possible de faire lorsque ces données sont intégrées, ainsi que les difficultés qui s'y rapportent. Un cadre de référence offre la possibilité d'influer sur l'élaboration des politiques d'efficacité énergétique et d'en appuyer le suivi à un niveau de précision qui n'était pas possible auparavant.

Mots clés: parc bâti, consommation, données, base de données, statistiques énergétiques, énergie, politique fondée sur des données probantes, cadre de référence     

Modelling a whole building stock: domestic,non-domestic and mixed use

ABSTRACT

Work on energy use in buildings – in university research, professional practice and government – has tended to draw a broad distinction between ‘the domestic stock’ and ‘the non-domestic stock’. A further tendency has been to focus attention on types of non-domestic buildings devoted to single uses (e.g. offices, shops or hospitals). This paper reports an empirical research programme in which the complete building stock in large areas of England and Wales is comprehensively represented in great detail, using a new method and model called 3DStock. The model breaks down activities by floor level and within each floor of every building. The results show that the extent of mixing of uses is much greater than has previously been acknowledged, especially towards the centres and in the older parts of towns and cities. These mixed-activity buildings are sometimes relatively simple combinations of domestic and non-domestic, e.g. urban retail with flats above, while others are complex mixtures of different non-domestic activities. The model can be used to investigate how these complex relationships influence energy use. It is argued that, at the larger scale, explicit account needs to be taken of the mixing of uses in future stock models for research and policy-making.     

Energy use in non-domestic buildings: the UK government's new evidence base

Policy for reducing carbon emissions from non-domestic buildings in the UK relies at present on survey and modelling work carried out in the 1990s. The UK government's Department of Energy and Climate Change (DECC) is engaged in a programme of new research to update this evidence base. The work has two main components. The first is a database – the National Energy Efficiency Data framework (NEED) – in which floor area and activity data for non-domestic premises are being linked to electricity and gas consumption at the individual property level. The second is a research project of sample surveys designed to elicit information about buildings and energy use, but also opportunities for abatement and the behavioural and organizational factors affecting efficiency improvements. A pilot survey of the food and mixed retail sector has been carried out in advance of further surveys of the entire range of building types. The research programme is described along with some of the methodological problems it raises.     

Mortality analysis of an urban building stock

Research is presented on the estimation of the lifespan of cohorts of buildings and building stocks. This is based on the analysis of extensive longitudinal data of the 55?000 buildings in the City of Zurich from 1832 and 2010. The survival probability from different perspectives considers age, construction periods, and demolition periods for both existing and demolished buildings. Survival probability is established using a Kaplan–Meier estimator. A more in-depth approach to the mortality of buildings is then determined by differentiating building age, use, size and geographical situation (district). The use of a common geographical information system (GIS) allows longitudinal building data to be linked to a geographical hierarchy of three levels of analysis (city, district and building) accounting for the different granularity on each level (neighbourhoods, quarters, building parts). A comparison of the two methods indicates that the choice of the observed time periods can lead to very different results. The analysis of the three levels shows the possibilities and limits of combined statistical and historical approaches. Mortality analysis is a promising approach to inform policy and practice; it could become a new link between long-term scenario planning, construction policies and institutional regimes.     

Retrofitting the existing UK building stock

The recent report of the Intergovernmental Panel on Climate Change (IPCC) confirms both the seriousness of the climate change challenge and the deep carbon emission reductions that are needed to avoid the worst consequences. A large fraction of those emissions come from existing buildings, and the special issue of Building Research and Information entitled ‘Climate Change: National Building Stocks’ (2007) (volume 35, number 4) describes both the range of buildings and emission reduction measures being undertaken in a number of countries. The challenge for the UK is set in an international context. Based on this information, a number of measures are suggested on a national scale that might achieve an 80% reduction in emissions by 2050.

Le récent rapport du Groupe d'experts intergouvernemental sur l'évolution du climat (GIEC) confirme à la fois la gravité du défi que pose le changement climatique et l'ampleur de la réduction des émission de carbone qui sont nécessaires pour éviter les pires conséquences. Une partie importante de ces émissions provient du parc de logements existant, et le numéro spécial de Building Research and Information intitulé « Changement climatique: les parcs de logements nationaux » (2007) (volume 35, N° 4) décrit à la fois l'éventail des logements et les mesures de réduction des émissions qui sont mises en ?uvre dans un certain nombre de pays. Le défi qui se pose au Royaume-Uni se situe dans un contexte international. Sur la base de ces informations, il est proposé un certain nombre de mesures à prendre au niveau national, qui pourraient permettre d'obtenir une réduction de 80% des émissions d'ici à 2050.

Mots clés: parc de logements, réduction du dioxyde de carbone (CO₂), intensité carbone, changement climatique, politique publique, Royaume-Uni     

Quantifying the impact of building envelope condition on energy use

ABSTRACT

The gap between the architectural information and the as-is building condition has been known as one of the pivotal factors influencing deviations between actual and predicted building energy consumption. Despite such significance, quantifying the impact of deviated building information on energy use has not been fully investigated. This paper explores building information modelling (BIM)-driven experimental simulation to quantify the impact of building envelope condition on energy use, which can infer the impact of reflecting the as-is building conditions in as-designed BIMs on the reliability of energy analysis. First, BIM-driven energy simulations are conducted with varied thermo-physical properties of building envelope elements in gbXML-based BIMs under different climate conditions. Building upon the impacting factor for energy analysis (IFEA), the simulation results are then used to infer the impact of the deviated building condition on energy consumption. Through case studies, it is observed that the annual energy consumption of a residential building can deviate by 18–20%, whereas thermal resistances of exterior walls can deviate by 1?m²K/W. This paper validates quantitatively the potential benefits of reflecting the as-is building condition in BIM-based energy performance analysis. This provides practitioners with insights into how to improve the reliability of energy analysis of existing buildings.     

Analysis of energy and carbon flows in the future Norwegian dwelling stock

A dynamic analysis of future energy and carbon flows (2000–2050) is performed on the aggregated residential building stock in Norway. The basis for the analysis is a dynamic material flow analysis of floor areas and the main building materials. By adding energy intensity assumptions for space heating, water heating, domestic electrical appliances and embodied energy in construction materials, the future corresponding delivered energy demand is calculated. This forms the basis for life cycle estimation of the future direct and indirect greenhouse gas (GHG) emissions. The predicted demand for delivered energy in 2025 will increase by 24.0% and 12.5% above those for 2000 and 2010, respectively, and then remain stable towards 2050. Energy savings per unit of floor area are counterbalanced by growth in the building stock. The very high influence of energy technology assumptions within the electricity generation market is demonstrated, along with the large differences between using attributional and consequential life cycle assessment principles in the calculation of future emissions. Future electricity demand met by marginal power generation technologies in the European market will yield substantially higher GHG emissions. The simulations demonstrate the policy, strategy, and practical challenges in achieving significant long-term energy and GHG emission reductions from the residential building stock in a country with a rapidly growing population.

Une analyse dynamique des flux futurs d'énergie et de carbone (2000-2050) est réalisée en Norvège sur l'ensemble du parc de logements (immeubles résidentiels). La base de l'analyse consiste en une analyse dynamique des flux de matières des surfaces au sol et des principaux matériaux de construction. En ajoutant des hypothèses relatives à l'intensité énergétique concernant le chauffage d'ambiance, la production d'eau chaude, les appareils électroménagers et l'énergie intrinsèque des matériaux de construction, la demande future correspondante en énergie livrée est calculée. Ceci constitue la base pour l'estimation du cycle de vie des futures émissions directes et indirectes de gaz à effet de serre (GES). La demande prévue d'énergie livrée en 2025 sera en augmentation de 24,0% et de 12,5%, respectivement, par rapport à la demande de 2000 et à celle de 2010, puis demeurera stable vers 2050. Les économies d'énergie par unité de surface au sol sont contrebalancées par la croissance du parc bâti. Démonstration est faite de la très forte influence des hypothèses relatives aux technologies énergétiques dans le marché de la production d'électricité, ainsi que des grandes différences existant entre le fait d'utiliser, pour le calcul des émissions futures, les principes d'une analyse attributionnelle et ceux d'une analyse conséquentielle du cycle de vie. La demande future d'électricité satisfaite par les technologies marginales de production d'électricité dans le marché européen générera des émissions de gaz à effet de serre sensiblement plus élevées. Les simulations montrent les défis qui se posent en termes de politique, de stratégie et sur le plan pratique, pour réaliser des réductions à long terme importantes de la consommation énergétique et des émissions de GES provenant du parc bâti résidentiel.

secteur du bâtiment?parc bâti?bâtiments?réduction du CO₂?consommation énergétique?émissions de gaz à effet de serre?analyse des flux de matières?atténuation?Norvège     

Carbon reductions and building regulations: the case of Norwegian mountain cabins

What are the limitations of regulatory measures to decrease environmental impacts of buildings? The case of Norway's wood-fired mountain cabins is used to explore whether strict energy-efficiency requirements in building regulations are appropriate and effective. A self-service (holiday) cabin is analysed in three different scenarios. The carbon emissions from the extra material required to meet the new regulations are calculated and compared with the emissions saved by the expected decrease in operational energy demand over a 50-year life cycle. The results show that in all three scenarios the carbon emissions from the extra material use and their transport outweighs the savings from reduced heating. As expected, the frequency of use (occupancy rate) is shown to be an important variable to determine the usefulness of technical upgrading. Alternative measures for decreased environmental impacts are considered. Suggested solutions for long-term reductions in carbon emissions for wood-fired mountain cabins are area efficiency (reduced floor area), low-carbon materials and the reuse of components instead of improved U-values. Regulatory measures that create universal standards for all buildings fail to account for particular circumstances and create revenge effects. Increased flexibility in regulatory mechanisms could reduce these problems.

Quelles sont les limites des mesures réglementaires visant à réduire les incidences environnementales des bâtiments? Le cas des chalets de montagne de Norvège à chauffage au bois est utilisé pour examiner si des obligations strictes d'efficacité énergétique dans la réglementation de la construction sont adaptées et efficaces. Un chalet (de vacances) en libre service est analysé selon trois scénarios différents. Les émissions de carbone provenant des matériaux supplémentaires nécessaires pour satisfaire à la nouvelle réglementation sont calculées et comparées aux émissions économisées par la réduction prévue de la demande d'énergie opérationnelle sur un cycle de vie de 50 ans. Les résultats montrent que dans chacun des trois scénarios les émissions de carbone provenant de l'utilisation de matériaux supplémentaires et de leur transport l'emportent sur les économies provenant des réductions de chauffage. Il est montré que, comme prévu, la fréquence d'utilisation (le taux d'occupation) est une variable importante pour déterminer la mise à niveau technique. Des mesures alternatives propres à réduire les incidences environnementales sont envisagées. Les solutions permettant de réduire sur le long terme les émissions de carbone des chalets de montagne à chauffage au bois sont le rendement de surface (surface au sol réduite), les matériaux bas carbone et la réutilisation des composants plutôt qu'une amélioration du coefficient K. Les mesures réglementaires qui établissent des normes universelles pour tous les bâtiments sont incapables de rendre compte de circonstances particulières et créent des effets pervers. Une plus grande souplesse des mécanismes réglementaires pourrait réduire ces problèmes.

Mots clés: réglementation de la construction?énergie intrinsèque?énergie, incidences environnementales?émissions de gaz à effet de serre?analyse du cycle de vie (ACV)?bâtiments bas carbone     

What next for energy-related building regulations?: the occupancy phase

Building regulations are important policy instruments for increasing building energy efficiency. However, when it comes to actual energy use, studies have shown that improvements in building energy efficiency are offset by changes in the inhabitants’ comfort practices. Nevertheless, the improvement of energy efficiency continues to be a cornerstone in building regulations, with no consideration of how this simultaneously influences everyday practices. The example of Danish building regulations, which are among the strictest in Europe, is critically reviewed for the implications regulatory design can have for reducing energy consumption. Based on readings of policy documents, consultancy reports and research papers from the last two decades, this paper outlines where things go amiss during a building’s lifetime if a user perspective is excluded. The focus is on three phases: the development of new building technologies, the design and construction of buildings, and occupancy. The question of how building regulations could be redesigned to regulate energy use better is explored, along with what research and strategies are needed within four domains: developing alternative measures to energy per square meter; developing more advanced models simulating occupancy; improving feedback technologies’ usability; and the increased use of commissioning and post-occupancy evaluations.     

Tracking,Tagging and Scanning the City

The proliferation of social media and software, such as building information modelling (BIM), has led to an unprecedented accumulation of data in the last few years, which can be tracked, tagged and scanned.With it, buildings and cities have been transformed into portals for information. Andrew Hudson-Smith , Director at the Centre for Advanced Spatial Analysis, University College London (UCL), describes how the ability to use emerging urban analytic tool kits provides the possibility of a real-time view of the city and a crystal-ball-like glimpse into urban networks of the future.