Stakeholder Specific Multi-Scale Spatial Representation of Urban Building-Stocks

Urban building-stocks use a significant amount of resources and energy. At the same time, theyhave a large potential for energy efficiency measures (EEM). To support decision-making and planning, spatial building-stock models are used to examine the current state and future development of urbanbuilding-stocks. While these models normally focus on specific cities, generic and broad stakeholder groups such as planners and policy makers are often targeted. Consequently, the visualization and communication of results are not tailored to these stakeholders. The aim of this paper is to explore the possibilities of mapping and representing energy use of urban building-stocks at different levels of aggregation and spatial distributions, to communicate with specific stakeholders involved in the urban development process. This paper uses a differentiated building-stock description based on building-specific data andmeasured energy use fromenergy performance certificates formulti-family buildings (MFB) in the city of Gothenburg. The building-stock description treats every building as unique, allowing results to be provided at any level of aggregation to suit the needs of the specific stakeholders involved. Calculated energy use of the existing stock is within 10% of the measured energy use. The potential for EEM in the existing stock is negated by the increased energy use due to new construction until 2035, using a development scenario based on current renovation rates and planned developments. Visualizations of the current energy use of the stock as well as the impact of renovation and new construction are provided, targeting specific local stakeholders

A differentiated description of building-stocks for a georeferenced urban bottom-up building-stock model

Several building-stock modelling techniques have been employed to investigate the impact of energy efficiency measures (EEM), where the description of the building-stock generally consists of an age-type classification to specify building characteristics for groups of buildings. Such descriptions lack the appropriate level of detail to differentiate the potential for EEM within age groups. This paper proposes a methodology for building-stock description using building-specific data and measured energy use to augment an age-type building-stock classification. By integrating building characteristics from energy performance certificates, measured energy use and envelope areas from a 2.5D GIS model, the building-stock description reflects the heterogeneity of the building-stock. The proposed method is validated using a local building portfolio (N = 433) in the city of Gothenburg, where modelled results for space heating and domestic hot water are compared to data from measurements, both on an individual building level and for the entire portfolio. Calculated energy use based on the building-stock description of the portfolio differ less than 3% from measured values, with 42% of the individual buildings being within a 20% margin of measured energy use indicating further work is needed to reduce or quantify the uncertainty on a building level

Demand response potential of electrical space heating in Swedish single-family dwellings

This paper investigates the potential and economics of electrical space heating in Swedish single-family dwellings (SFDs) to provide Demand Response (DR) for the electricity load in Sweden.A dynamic and detailed building-stock model, is used to calculate the net energy demand by end-use of a set of sample buildings taken as representative of all Swedish SFDs with electrical heating. A new sub-model optimizes the dispatch of heating systems on an hourly basis, for each representative building, minimizing the cost of electricity purchased from the hourly spot market.The analysis of the Swedish SFD buildings indicates a technical DR capacity potential of 7.3 GW, which is considerable and can be used for the management of intermittent electricity generation. This potential could also prove to be valuable in the operating reserve market. However, this requires that the DR, rather than being governed by a single hourly electricity price signal, would instead be subject to a more centralized control. The modeling shows that DR can be expected to result in up to 5.5 GW of decreased load and 4.4 GW of increased load, if applying current Swedish electricity prices. The modeling shows that DR shifts up to 1.46 TWh of electric heating, corresponding to 1% of total Swedish electricity demand. The potential savings from DR for individual SFDs is found to be low, 0.9–330 €/year, given current Swedish electricity prices

Challenges and Lessons Learned in Applying Sensitivity Analysis to Building Stock Energy Models

Uncertainty Analysis (UA) and Sensitivity Analysis (SA) offer essential tools to determine the limits of inference of a model and explore the factors which have the most effect on the model outputs. However, despite a well-established body of work applying UA and SA to models of individual buildings, a review of the literature relating to energy models for larger groups of buildings undertaken by Fennell et al. (2019) highlighted very limited application at larger scales. This contribution describes the efforts undertaken by a group of research teams in the context of IEA-EBC Annex 70 working with a diverse set of Building Stock Models (BSMs) to apply global sensitivity analysis methods and compare their results. Since BSMs are a class of model defined by their output and coverage rather than their structure and inputs, they represent a diverse set of modelling approaches. Key challenges for the application of SA are identified and explored, including the influence of model form, input data types and model outputs. This study combines results from 7 different modelling teams, each using different models across a range of urban areas to explore these challenges and begin the process of developing standardised workflows for SA of BSMs

Modelling Energy Conservation and CO2 Mitigation in the European Building Stock

This thesis investigates energy conservation in building stocks with the aim of developing a methodology that can be applied to the national building stocks of the European Union (EU). For this purpose, a bottom-up building-stock model and a methodology for describing the building-stock have been established. The model is based on a one-zone building energy balance, which provides the hourly net energy demand for all end-uses and which has been validated by empirical and comparative means for selected buildings. The results for representative buildings are subsequently extrapolated to the entire building stock with respect to net and final energy demand, associated CO2 emissions, and costs for implementing a portfolio of energy conservation measures (ECMs). The methodology for building stock aggregation through archetype buildings comprises the following elements: (1) segmentation, in which the number of archetype buildings required to represent the entire stock is decided according to building type, construction year, heating system, and climate zone; (2) characterization, whereby each archetype is described in terms of its physical and technical characteristics; (3) quantification, whereby the number of buildings in the stock represented by each archetype building is determined. The archetype description is used as an input to the model, from which the final energy use is calculated, and the results are validated by comparison with the available statistics. The archetype description has been developed and validated for the building stocks of France, Germany, Spain and UK, which account for half of the final energy use of the residential and non-residential buildings in the EU-27 countries.Using the building stock model to apply various ECMs to the Swedish residential building stock and the entire Spanish residential and non-residential building stock, which are representative of Northern and Southern EU buildings, respectively, the final energy demands of the Swedish and Spanish building stock are found to be reduced by 50%. In both countries, the different forms of envelope upgrades confer the largest technical potential reductions for all buildings. However, other ECMs with significant potentials differ between the two countries and subsectors. The levels of CO2 emissions from the Swedish residential buildings and the Spanish buildings can be reduced by 60%–70%. Although the application of the ECMs generally reduces CO2 emissions, the effects of measures that reduce electricity use for lighting and appliances rely on whether the saved electricity production is less or more CO2-intensive than the fuel mix used for space heating. Techno-economical potential reductions of energy demand by 20%–30% are identified for Sweden and Spain, corresponding to CO2 emissions reductions of 40%–50%. These potentials increase when packages of ECMs are applied. Furthermore, the packages were more cost-effective than the individual ECMs. The market potentials identified are substantially lower than the techno-economical potentials. If the techno-economic potentials identified in this work are to be implemented, there is a need for strong policy measures to influence stakeholder actions

Energy efficiency and carbon dioxide mitigation in building stocks-

This thesis investigates the implementation of energy-saving measures (ESM) in existing building stocks from an energy systems perspective. The effects of the measures are assessed in terms of net and delivered energy levels, carbon dioxide (CO2) emissions, and the costs for implementing the measures. For this assessment, abottom-up engineering energy balance model was developed that facilitates modelling of an entire building stock, i.e., the Energy, Carbon and Cost Assessment for BuildingStocks (ECCABS) model. The model was validated by modelling a residential building in Sweden and an office building in Spain, and by comparing the results from the model developed in this work with the measurements and results from a detailed heat balance model. The simplified model gives satisfactory results. When the model was applied to 1400 buildings that were chosen as being representative of the Swedish residential building stock, the results showed good agreement with the available statistics on energy use in the Swedish residential building stock.Application of the investigated ESM would reduce the net energy demand of the Swedish residential sector by 55%. The measures that would provide the greatest savings are installation of heat recovery systems (22%) and reduction of the indoor temperature (14%). The ECCABS model indicated that the upgrading of the U-value of basements and the U-value of facades and the replacement of windows would provide an annual energy saving of about 7% each. The net potential reductions in CO2 emissions arising from the implementation of the ESM would be low, since the energy supply in Sweden generally associated with low levels of CO2 emissions. In addition, measures that reduce the electricity for lighting and appliances would increase CO2 emissions, since the electricity saved is less CO2-intensive than the fuel mix used for the corresponding increase in space heating.The model is also applied to evaluate the profitability of ESM for the Swedish residential stock under different scenarios for the development of the energy system, particularly with respect to the prices of energy carriers used as fuels in the buildings. Three scenarios were investigated: a baseline scenario that assumes current energy prices and a continuation of the present trends in energy use, and two climate change mitigation scenarios.Already in the Baseline scenario, energy use could be reduced by 30% by implementing profitable ESM, whereas the climate change mitigation scenarios generate only modest increases in profitable energy reduction in spite of higher energy prices. The most profitable ESM are the same in all three scenarios and they involve: (1) a reduction by 50% of electricity for lighting and appliances; (2) a reduction of indoor temperature down to 20\ubaC; and (3) heat recovery for single-family dwellings. In contrast, the modelling reveals that the replacement of existing hydropumps with more efficient ones and the retrofitting of the building envelope are the most expensive ESM. The three scenarios give similar average annual costs for the ESM for the period 2010-2050. However, it cannot be expected that all of the cost efficiency potentials described in this thesis will be seized. Thus, further work is required to investigate how the energy-saving potentials identified in this work can be implemented

Cost-Effectiveness of Retrofitting Swedish Buildings

This chapter presents potentials for energy conservation through energy retrofitting of existing Swedish buildings, including residential and nonresidential buildings. The Swedish building stock is described with 1800 representative buildings, in a combination of sample and archetype buildings, and is modeled with a dynamic and detailed building-stock model. Ten individual energy conservation measures and 6 packages of measures are considered. The chapter also presents how the cost-effectiveness of the measures depends on energy prices, discount rates, and the assumed investment costs for the different measures. The results are presented and discussed separately for residential buildings, divided into single-family dwellings and multifamily dwellings, and nonresidential buildings

Transforming the energy system in V\ue4stra G\uf6taland and Halland - the potential for energy savings and CO2 emissions reductions in the building sector

This report belongs to Work Package 2 of the project Sustainable use of energy carriers in the KASK region (http://www.kask-energy.eu/project). The overall target for the project is to study how improving energy efficiency and large scale integration of renewable energy can contribute to economic and environmental sustainable development of the Kattegat-Skagerrak region (KASK). Possible development routes are studied with today\u27s energy situation as starting point, to show how the energy system in the region can be designed towards a more sustainable system in short (2020), medium (2030) and long term (2050). The project is split in four different work packages. Work package 2 includes detailed studies of how to improve energy efficiency in key industries and in the existing building stock, as well as a study of integration of wind/renewable energy into the existing energy net. This technical report focuses on the results for the building sector and, therefore, presents the methodological details in the appendixes, as follows: Chapter 1describes the building stock of KASK with respect to the characteristics that are determinant for the buildings\ub4 energy use and associated CO2 emissions, i.e. number of buildings and dwellings/premises, heated floor areas and fuel use. The method and data sources used are presented in Appendix A, the validation of the description is presented in Appendix B. CO2 emissions data are presented in Appendix C. Chapter 2 presents the different individual ECMs and packages of ECMs investigated in this work. Chapter 3 reports of the obtained technical, techno-economic and market potentials for the Swedish KASK. Detailed results for V\ue4stra G\uf6taland and Halland, and for their residential and non-residential subsectors are provided in the Appendix D. Chapter 4 summarizes the main findings and identifies challenges