Diffusion of energy-efficient technologies in EU residential buildings

Residential buildings constitute approximately 75% of the European building stock, accounting for around 30% of the EU\ub4s overall energy demand and emissions. They also represent one of the biggest sources of energy saving potential, thus holding a crucial role in achieving EU carbon targets. Technology options to decrease residential building’s energy demand to nZEB standards are readily available and, in many cases, economically viable. However, they are not being deployed at the required rate to achieve GHG emission reduction targets. The divergence between the techno-economic potential and actual market behaviour suggests that in the European housing context the economic viability of energy-efficiency technologies (EETs) is not sufficiently acknowledged or appealing to motivate the necessary investments. In order to bridge the energy-efficiency gap and favour the low-carbon transformation of residential buildings in Europe, additional policy measures need to be developed. In a diverse national organisation such as the EU, it is particularly essential to have a national and cross-national scale knowledge to generate an appropriate combination of common and country-specific policies. This knowledge should be based on solid comprehension of the current national and cross-national market conditions affecting the diffusion of EETs. Against this background, this PhD thesis builds on the research field of technology diffusion with the overall goal of advancing the understanding of the EET adoption in EU residential building stock. In particular, the following research questions are posed: (1) Who are the key decision-makers and persuaders in the technology selection, across building typologies, project types, and EU member states? (2) What are the drivers and barriers for EETs across the EU member states? and (3) What are the EET diffusion gradients across building typologies, project types and EU member states?To address these research questions while allowing for cross-country comparison of the results, a methodology framework is developed. First, an online survey addressing these research questions is designed and distributed across eight European countries, namely Italy, Spain, Germany, Poland, United Kingdom, France, Belgium, and the Netherlands. The retrieved information is then analysed using a bundle of quantitative methods, specifically social network analysis (SNA), discrete choice modelling, and Chi2 and Cramers V tests. Results from this study show that the individual level of power and communication varies across the different cases and countries. However, in all instances, multiple stakeholders interact, thereby potentially influencing each other during the technology selection. The potential technology adopters are identified as having the highest power in the decisions, often followed by engineers, architects, and installers. In terms of barriers and drivers, techno-economic arguments are most relevant across most of the geographies and technology solutions, with the exception of electric storage in Germany. Finally, the most often implemented EET measures across the sampled countries and building projects are maintenance of the wall and envelope, new energy-generation systems, and maintenance of the roof or envelope combined with an upgrade of the energy generation system. Findings from this thesis can contribute to the understanding of EET diffusion in the EU residential building stock. This information, in turn, can support the formulation of evidence-based policies and actions, aimed at stimulating the adoption of these technologies

On the Uptake of Energy Efficiency Technologies in European Residential Buildings

Residential buildings constitute approximately 75% of the European building stock, accounting for circa 30% of the EU\ub4s overall energy demand and emissions. They also represent one of the biggest sources of energy saving potential, holding a crucial role in achieving EU carbon targets. Despite technology options to decrease residential building’s energy demand to nZEB standards are readily available and, in many cases, economically viable, they are not being deployed at the required rate to achieve greenhouse gas emission reduction targets. The divergence between the technoeconomic potential and actual market behaviour, so-called ‘energy efficiency gap’, suggests that, in the European housing context, the economic viability of energy efficiency technologies - specifically the cost of potential energy savings (commonly considered as the only financial benefit) - is not sufficiently acknowledged or appealing to motivate the necessary investments. In order to bridge the energy efficiency gap and favour the low-carbon transformation of residential buildings in Europe, additional national policy measures need to be developed. Policy instruments can be classified into push- (e.g. regulatory and control instruments), and pull-mechanisms, (e.g. economic or fiscal incentives and support tools for voluntary action). To ensure their effectiveness, these instruments should be designed based on solid comprehension of the current national market conditions and dynamics. Hence addressing the market barriers existing in the respective countries in the uptake of energy efficiency technology measures.Various sources point out at the lack of scientific knowledge in this arena. In this light, the goal of this licentiate thesis is to gather information to contribute to the scientific expertise and support the reduction of the energy efficiency gap. The first part of the work is, therefore, dedicated to better understand the intellectual base in the uptake energy efficiency technology in the European residential building stock and settle a specific field of study for the Ph.D. project. This is done via a bibliometric analysis. 954 scientific articles and their references are analysed, a visual knowledge structure of the field is modelled, and key papers are identified. Results from this process show that this field has gained considerable momentum in the past decade but still lacks a comprehensive pan-European cross-country understanding. Based on the knowledge gaps and research needs defined by the literature review, complimented with discussion with market experts, research questions are formulated. These questions demand for empirical evidence in the uptake of energy efficiency measures in residential buildings in Europe. To collect this testimony and address the research questions, an online survey is designed and operationalized. The methodology aims for country-scale information and cross-country comparability of the results. Given the complex and fragmented nature of the residential building market and different phases in the building’s life cycle, a stratified sample approach and survey intelligence are developed. The stratified sample consists of three stratification axes, based on the three main elements or agents of the building projects. These are stakeholder, building typology and project type. The survey has been distributed in Germany, United Kingdom, France, Spain, Italy, the Netherlands and Poland. The status of the survey distribution in each country as of April 2019 is presented in this Licentiate. Finally, conclusions obtained from the development of the overall methodology are described, as well as selected research contributions. This is followed by the description of future work within the scope of the Ph.D. project and connection to other research fields

Drivers and barriers to energy-efficient technologies (EETs) in EU residential buildings

To achieve carbon targets, the European Union (EU) aims to promote nearly zero-energy buildings (nZEB). To enable the necessary transition, technical solutions need to converge with socio-economic factors, such values and awareness of stakeholders involved in the decision-making process. In this light, the aim of this paper is to characterise perceived drivers and barriers to nine energy-efficient technologies (EET), according to key decision-makers\u27 and persuaders of the technology selection in the EU residential building context. Results are collected across eight EU countries, i.e. Belgium (BE), Germany (DE), Spain (ES), France (FR), Italy (IT), Netherlands (NL), Poland (PL), and United Kingdom (UK). The stakeholders’ selected are architects, construction companies, engineers, installers and demand-side actors. Data from a multi-country survey is analysed to calculate the share of 15 drivers and 21 barriers (aggregated to 5 groups), being selected for each EET and country. The 5 groups considered to analyse drivers and barriers are environmental, technical, economic, social, legal. The perceived barriers and drivers were further studied for their association across the countries using the Pearson\u27s Chi2 and a Cramer\u27s V tests. The results demonstrate that across all EETs and countries, the technical and economic driver groups are perceived to have the highest potential to increase the implementation rate of EET. In terms of barriers, economic aspects are seen as the foremost reason that EET are not scaling faster. In both drivers and barriers legal aspects are the least often selected. In overall the barrier groups show significant variation across countries compared to driver groups. These findings provide an evidence-basis to better understand arguments in favour and against specific EETs and, in this way, support policy makers and other interested parties to increase the market share of the selected solutions

Innovation for Low-Rise Construction in the Urban Tropics: Utilization of Structural Bamboo for Cost-Efficient Housing

This paper deals with a cost-efficient construction technology using load bearing\ua0bamboo for urban low-rise housing in tropical Asia-Pacific. The potential of the technology\ua0to be applied at larger scale is discussed at the example of the Philippines as pilot country\ua0for its application. The assessment of alternative construction methods such as this one is\ua0motivated by a tremendous need for more affordable, sustainable and resilient housing\ua0around the globe. The urban poor, being the most underserved group in need of housing,\ua0often cannot afford conventional building technologies offered by the formal industry.\ua0Using locally available bamboo as structural component within the introduced standardized\ua0and quality controlled construction method is an entry point to provide performing and safe\ua0housing at lower cost. The paper highlights, however, that cost-efficiency and technical\ua0performance are not the only requirements for innovations to succeed on a market,\ua0especially due to the complex challenge of urban poor housing. Through learnings from the\ua0construction of 50 houses in the Philippines and interviews with various stakeholders along\ua0the value chain of the technology, barriers and opportunities for a scale-up are retrieved. For\ua0this paper, a conflated none-exhaustive overview of the identified aspects is documented. It\ua0was found that both barriers and opportunities directly linked to this technology are closely\ua0tied to a complex local value chain which ranges from upstream supply of raw material to\ua0downstream customer acceptance. The pilot application has shown further, that participatory\ua0product development reduces the acceptance barrier significantly by directly addressing the\ua0needs of low income customers. Material and skills availability, enabling policies and\ua0approval by legal entities as well as sustainability in supply of the organic raw material play\ua0important roles too. This complex set of interlinked aspects needs to be addressed according\ua0to targets in implementation-pace, and -scale as well as its intended social value creation.\ua0While multi-stakeholder participation is required for a successful up-scaling, a facilitating\ua0social enterprise, providing knowledge and services around the technology, can guide\ua0through the up-scaling

Energy Efficiency Measures and Data Needs. The Case of the European Building Portfolio Owners

In line with EU Directives, European building portfolio owners are required to bring their stock to nearly Zero Energy Building (nZEB) standards by 2050. To fulfil this goal in a timely and cost-effective manner, they will need to have a comprehensive understanding of their buildings’ condition, as well as consistent information on viable energy and low-carbon technology measures. Currently, in Europe, there is a lack of knowledge of what energyefficiency measures are being implemented in residential buildings. It is also unknown what are the decision-making processes behind the selection of these measures. On this basis, the aim of this study is to shed light on (1) what energy efficiency measures are currently carried out across European building portfolio owners (BPOs), (2) how are these measures selected (i.e. decisionmaking processes and information sources), and (3) what data would be needed to foster the uptake of low carbon energy efficiency technologies. The applied methodology combines desk research on scientific and grey literature, with findings in the field of building maintenance & operation. The later based on semi-structured interviews with 23 selected private and public BPOs across 7 European countries: Sweden, UK, Germany, Denmark, Italy, Spain and Switzerland. Results show that the most often implemented actions are the maintenance of the roof and the upgrade of the heating system. Measures are decided based on a combined planned and “reactive” (i.e. problem/solution) approach. The data that is typically used by BPOs is basic building information, such as gross floor area or year built. Although currently unavailable, the most often solicited evidence by the BPOS in favour of energy efficiency and low carbon technology measures is related to energy consumption and other user data

Diffusion of energy efficiency technologies in European residential buildings: A bibliometric analysis

Many studies have investigated different aspects in the decarbonisation of the European housing stock. However, a comprehensive quantitative analysis of the literature on the diffusion of energy efficiency technologies is still missing. We conducted a bibliometric analysis to better understand the knowledge base in the field energy efficiency technology diffusion in the European residential building stock. After the scanning and screening process, we identified 954 scientific articles pertinent to this topic. Through a co-citation network analysis, we generated a visual knowledge structure of the field and by the further investigation of the bibliography we were able to synthesize the state-of-the-art and answer to our initial research questions. Results of the co-citation network show a scattered and fragmented field in many domains. The descriptive analysis highlights this fragmentation, especially on a cross-country level among EU country members. Findings from this study contribute to map the scientific knowledge base in relation to technology diffusion in European residential building projects, identify relevant topic areas, visualize the links between the topics, as well as to recognize research gaps and opportunities. The methodology utilized in this paper proved to be viable approach to map and characterize the knowledge base within a field and can, therefore, be replicated in upcoming studies with analogous ambitions

Prioritizing deep renovation for housing portfolios

Cost-effectiveness of deep renovation has been assessed thoroughly on a building level. Such studies pro- vide limited guidance when prioritizing renovation measures for a building portfolio. On a stock level, building-stock modelling is commonly used to assess impact of renovation on a national and city level, targeting stakeholders operating at a planning or policy level. However, due to methodological choices and data availability, assessment of property owner portfolios is lacking. The aim of this paper is to cal- culate and spatially differentiate cost-effectiveness of deep renovation using equivalent annual cost and increase in assessed building value for a portfolio owner as a first step in prioritizing deep renovation within a building portfolio. A bottom-up engineering-based model is applied utilizing building-specific information for a municipal housing company portfolio in the City of Gothenburg, Sweden, consisting of 1803 multi-family buildings. Energy demand for space heating and hot-water is calibrated using mea- sured energy use from energy performance certificates. Deep renovation is assessed by applying a pack- age of measures across all buildings. Results show average energy use reduction across the portfolio of 51% to an average cost of 597 EUR/m 2 living area. While average energy cost savings account for 21% of equivalent annual cost, there are seven buildings where more than half the annual equivalent cost of renovation is covered by energy cost savings. Similarly, the distribution of change in assessed build- ing value is large for individual buildings, ranging from 0–23%. Aggregating results to larger areas tend to average out results while differences between individual buildings within areas persists. As such, the cost-effectiveness of deep renovation should be assessed on a building-by-building basis rather than for an area or neighbourhood. The results are intended as a first step in prioritizing deep renovation within a building portfolio and further detailed assessment is needed

Energy-efficient retrofit measures (EERM) in residential buildings: An application of discrete choice modelling

Cross-country evidence on the adoption of energy-efficient retrofit measures (EERMs) in residential buildings is critical to supporting the development of national and pan-European policies aimed at fostering the energy performance upgrade of the building stock. In this light, the aim of this paper is to advance in the understanding of the probability of certain EERMs taking place in eight EU countries, according to a set of parameters, such as building typology, project types, and motivation behind the project. Using these parameters collected via a multi-country online survey, a set of discrete-choice (conditional logit) models are estimated on the probability of selecting a choice of any combination of 33 EERMs across the sampled countries. Results show that actions related to the building envelope are the most often-addressed across countries and single building elements or technology measures have a higher probability of being implemented. The modelling framework developed in this study contributes to the scientific community in three ways: (1) establishing an empirical relationship among EERMs and project (i.e., retrofit and deep retrofit), (2) identifying commonalities and differences across the selected countries, and (3) quantifying the probabilities and market shares of various EERMs

Synthetic building stocks as a way to assess the energy demand and greenhouse gas emissions of national building stocks

In Europe, the final energy demand and greenhouse gas (GHG) emissions of residential and commercial building stocks account for approximately 40% of energy and emissions. A building stock model (BSM) is a method of assessing the energy demand and GHG emissions of building stocks and developing pathways for energy and GHG emission reduction. The most common approach to building stock modeling is to construct archetypes that are taken to representing large segments of the stock. This paper introduces a new method of building stock modeling based on the generation of synthetic building stocks. By drawing on relevant research, the developed methodology uses aggregate national data and combines it with various data sources to generate a disaggregated synthetic building stock. The methodology is implemented and validated for the residential building stock of Switzerland. The results demonstrate that the energy demand and GHG emissions can vary greatly across the stock. These and other indicators vary significantly within common building stock segments that consider only few attributes such as building type and construction period. Furthermore, the results indicate a separation of the stock in terms of GHG emissions between old fossil fuel-heated buildings and new and refurbished buildings that are heated by renewable energy. Generating a disaggregated synthetic building stock allows for a discrete representation of various building states. This enables a more realistic representation of past building stock alterations, such as refurbishment, compared with commonly used archetypes, and not relying on more extensive data sources and being able to accommodate a wide variation of data types. The developed methodology can be extended in numerous manners and lays groundwork for future studies

Next Generation Living Labs: Comprehensive Report

This report aims to expand on existing logic and knowledge of Living Labs and take into consideration the innovation ecosystems surrounding Living Labs.\ua0Through literature review and the lessons learned from the initiation and implementation of two Living Lab infrastructures in the Building Technology Accelerator Flagship Program (BTA), perspectives are offered focusing on Open Innovation ecosystems, Open Innovation organizational elements, co-creation and data system tools.\ua0The breakdown of the methods as well as the results derived have been synthesized and compiled in this report. Key lessons learned were summarized and categorized using the European Network of Living Labs (ENoLL) harmonization Cube. This was done to provide a more comprehensive set of suggestions for organizations connected to Living Labs transitioning towards Open Innovation and developing Next Generation Living Labs.We hope This report is a start towards the development of a comprehensive methodology for Living Lab infrastructures within the BTA network and points to important elements for this development