ALBERT

Beschreibung: The implementation of residential photovoltaics must increase more rapidly to combat climate change and its impacts. This challenge is addressed in this study by introducing a segmentation model in order to develop a theoretical and empirical foundation for understanding the heterogeneity of potential adopters. Data were collected by means of a survey among Dutch adopters (n = 1395) and the data is analysed with statistical descriptive analyses and nonparametric tests. The five segmentation groups are divided by the homeowners’ educational background or profession (technical, financial-economic or other) and level of environmental concern. The results demonstrate that the groups are substantial in size and that there are significant differences between these groups on personal characteristics such as homeowners’ level of environmental concern and the level of influence of their social network on their decision to adopt. In addition, significant differences are found between the groups on the perceived characteristics of the residential photovoltaics such as perceived complexity and aesthetics, and the amount of previous practice with other energy measures in their home. Accordingly, these insights can be used by policymakers and the public and private sectors to promote residential photovoltaics more effectively by targeting the segmentation groups more adequately. The different groups will be drawn to different aspects and therefore, a broader pallet of benefits must be presented; a mix of different communication channels must be used; objective and non-technical assistance in the decision-making must be offered; and different kind of products must be provided.

Beschreibung: Behavioural change is expected to play a significant role in the transformation to a more energy efficient built environment. Despite this, current evaluation practice of interventions often overlook behavioural aspects in their ambition of advancing our knowledge on transformative change. Moreover, little attention is paid to how different research perspectives on human behaviour can complement each other in providing a broader scope and deeper understanding of behavioural change. In this study, we acknowledge this gap, and assess the current evaluation practices on behaviour. The focus is on energy efficiency in the built environment in the Nordic countries, and evaluations undertaken by researchers. The assessment shows that the Nordic evaluations apply a variety of disciplinary approaches, but have only to a limited extent addressed a psychological understanding of individual behaviour and behavioural change. We analyse and discuss the potential contribution of environmental psychology in strengthening a cross disciplinary evaluation approach. In all, the results indicate the value of also adding environmental psychology, to provide a stronger cross disciplinary understanding of behavioural change, and the need to coordinate and combine evaluations departing from different disciplinary approaches, to improve understanding of the transformational process.

Beschreibung: In this paper, we present the energy-saving potential of using optimized control for centrifugal pump–driven water storages. For this purpose, a Simulink pump-pipe-storage model is used. The equations and transfer function for steady-state and transient system behavior are presented and verified. Two different control strategies—optimum constant flow rate and level guided speed control—are compared to an allegedly optimal-driven pump with constant rotational speed. Twelve centrifugal pumps between 1 and 120 kW nominal power are evaluated to analyze the influence of different system parameters. The system characteristics, which are the static head, dynamic head factor, and maximum filling head, are varied 25 times for each pump in consideration of the pump’s best efficiency point. Thus, 300 different systems are optimized for each control strategy and compared to the constant speed control. The results are analyzed and the relevant system’s parameters, which have the most significant impact on energy savings, are shown. This theoretical energy–saving potential is verified with measurements, which show the high impact of the part load losses of the frequency converter and the electric motor. A law for identifying and estimation potential energy savings is developed using this information. Four use cases are analyzed with this law. It is shown that for a cost-minimal operation, not only the savings potential but also the operating time is decisive.

Beschreibung: The effect of the location on the energy consumption of data centers has already been studied in detail on the macro-climatic level. To take advantage of these effects, however, it is usually necessary for the location of data centers to cross international borders. The influence of site changes within national borders and in a small radius of 〈 100 km has not yet been quantified. To investigate this, a dynamic mathematical model of the temperature-dependent components of a reference data center was created and the influence on the energy consumption in an area of 240 × 215 km in Germany was investigated. It could be shown that even small changes of the location within a 10 km radius of a location lead to annual energy savings in the recirculating chiller of 9.12% on average (maximum 56.58%). With a freedom of location of 100 km within national borders, savings of 37.35% on average (maximum 76.11%) are even possible. Location-dependent optimizations are therefore also relevant at local and national level with regard to their influence on energy consumption, and the consideration of mesoclimatic aspects should be an elementary part of the site selection process for data centers in the future.

Beschreibung: There are over 80 countries in the world that currently use some kind of energy label for electric household appliances. In Europe, as an example, a lot of appliances are obliged to have an energy label when shown for sale, including online. Energy labels give relevant information to the consumers to help them make an environmentally beneficial choice when buying a new appliance. However, the desire for an energy efficient appliance does not outweigh the wish for good performance. Therefore, some energy labels provide information about the performance of the appliance based on international performance measurement standards (hereafter: “international standards”). Indeed, within the one appliance, increased performance can often mean increased energy consumption, so a balance between these parameters needs to be made by product designers and users. Unlike measurements that are traceable to Systeme Internationale units through metrological traceability chains, there is no natural reference data for performance measurements. Therefore, some international standards use a reference machine to relate their testing results to. The comparison of test and reference machine eliminates variances, for example, due to the auxiliary materials used and the influence of manual preparation or assessment methods. Three international standards that are currently using reference machines are examined closely in this paper. It is assessed how the reference machines and their testing results are treated, whether the reference machines are comparable with their corresponding test machines and if the use of a reference machine can be considered beneficial for the testing procedure. Additionally, three key questions are developed that will indicate whether 13 other international standards for electric household appliances could also benefit from using a reference machine. The paper concludes with six recommendations for standardisation groups and energy policymakers that will help with deciding whether a reference machine should be implemented.

Beschreibung: In April 1989, the UK Prime Minister, Margaret Thatcher, convened a full cabinet meeting on climate change addressed by leading scientists. The presentation on mitigation of carbon dioxide emissions was made by the Head of the Energy Technology Support Unit (ETSU), Ken Currie, and identified the key potential options for mitigation by 2020. In this paper, we compare the mitigation potential identified for each proposed option with the 2019 outturn. The largest mitigation options identified were improved end use energy efficiency across the economy and the generation and use of low carbon electricity. Our analysis finds that these have been the key options adopted. Reductions in primary energy use, resulting from improvements in energy efficiency were concentrated in the period 2005–2012 which in 1989 were widely considered to be ambitious. Decarbonisation of electricity has been achieved by the displacement of coal, initially by gas and more recently by renewable electricity. Renewable electricity has exceeded 1989 expectations in the last 5 years and is now the biggest source of CO2 reductions from electricity generation. The contribution envisaged by nuclear electricity has not occurred, largely due its failure to compete in liberalised generation markets. In all cases, the policy environment has been important. We draw lessons for mitigation options to achieve the goal of net zero emissions in the next 30 years. The contribution of demand side and other modular options will remain crucial, as mass-produced technologies tend to improve more quickly than those requiring large construction projects. Environmental, social and political factors will be important, so analysis should not be a purely techno-economic assessment.

Beschreibung: In this paper, we analyze the level of efficiency in the use of electricity in the European residential sector relying on a cross-sectional data set comprised of 1375 households located in Italy, the Netherlands, and Switzerland and observed in 2016. To do this, we estimate an electricity demand frontier function using a stochastic frontier approach. The empirical results show that the residential sector in these three European countries could save approximately 20% of its total electricity consumption on average if it improves the level of efficiency in the use of electricity. These figures are in line with recent studies for Switzerland and for the US residential sector. Moreover, we link energy efficiency to energy-related financial literacy. We find that while energy-relevant knowledge per se does not play a significant role, stronger cognitive abilities are associated with higher levels of energy efficiency.

Beschreibung: Recent evidence indicates that the key sources of energy for the zero carbon transition will be renewable electricity sources. The most rapidly expanding sources, photovoltaics and wind produce work, as electricity, directly rather than via heat engines. Making the assumption that these will be the dominant sources of energy in a future zero carbon system, the paper makes two new related and innovative contributions to the literature on the energy transition. First, it shows that the energy transition will be more than just a shift away from carbonaceous fuels, and that it is more usefully thought of as including a systemic shift from heat-producing to work-producing energy sources. Secondly, it shows that this enables very large improvements in the conversion efficiency of final energy, through the use of electricity and hydrogen, in particular in heating and transportation. The paper presents a thought experiment showing a reduction in final energy demand of up to 40% is likely from this effect alone. Technical standards and product regulation for end use conversion efficiency and/or service delivery efficiency seem likely to be key policy instruments.

Beschreibung: During the last few decades, focus on measures for energy conservation in buildings has increased considerably. The European Commission implemented the Energy Performance of Buildings Directive, which gave instructions to the member states about how to reduce energy consumption in residential and non-residential buildings. In the process of making the building sector more energy efficient, the building codes generally have become stricter with some simplifications applied in the requirements. For swimming facilities in Norway, these simplifications are undermining the purpose of the code by excluding the energy use related to the operation of swimming pools, which is the main part of the energy use in this building category. In other words, the energy use related to operation of the facility is not regulated. Furthermore, guidelines for the planning and operation of these types of facilities are outdated and research for this building category is sparse. These three aspects mean that there is a considerable potential for improvement. This paper presents a comprehensive literature review with bibliometric and thematic analyses of the contextualized research in swimming facilities from a heating, ventilation, and air-conditioning perspective. It maps the major trends during the past few decades, where areas like solar heating for outdoor pools, energy consumption, and air quality stand out. Except for air quality and disinfection by-products, research on these facilities is highly fragmented without any strong contributors to the various fields. Graphical abstract

Beschreibung: This study aims to provide detailed information on the key technologies that utilize renewables for decarbonization and electrification of the residential heating sector. To contextualize and compare the economics of the technologies, a levelized cost model is employed to perform a comparative analysis for a dense urban area in Switzerland. The outcome shows that decarbonization of the heat supply with a dominant share of renewables is feasible, but it is challenged by the high cost of some options. In the given context (current energy and CO2 prices, no coercive measures), the rapid shift from conventional boilers to electrification via decentralized heat pumps and/or the introduction of targeted small-scale thermal energy networks utilizing cheap local resources like industrial excess heat is the most viable option. The replacement of natural gas boilers with electrification technologies also is recommendable because it would result in a sixfold reduction in specific CO2 emissions. Wide-scale application of heat pumps may require significant electricity grid reinforcement which ultimately may escalate the costs. Large-scale district heating systems are currently relatively expensive due to the high network costs and require a sustainable financing mechanism. To speed up the energy transition, policy interventions by the government are urgently needed.

Beschreibung: Nowadays, one of the basic requirements for thermally upgraded buildings involves limitation in CO2 emission even by over 90%. To fulfil these criteria, it is necessary to use alternative energy sources and photovoltaics constitutes a reasonable option for this. This paper addresses an analysis of the efficiency and profitability of a photovoltaic system located in the geometric center of Europe-Poland, where the intensity of solar irradiation is not very high compared to other European countries. The difference of total solar radiation density between Poland and Malta is 49.2%, from analysis based on SolarGIS base. The PV Lighthouse calculator was used for global power density and photon current examination for a Polish city and locations of the highest and the lowest solar radiation values, Malta and Finland, respectively. This case study concerns a thermally upgraded building; a gas boiler was replaced by a heat pump supported by an off-grid PV system. To achieve a reduction in CO2 emission of 90%, it is necessary to install 182 PV cells, which generates high investment costs. An investment is entirely profitable with 70% of funding with Simple Pay Back Time, SPBT~7 years although Net Present Value, NPV〉0; Internal Rate of Return, IRR=10.6%.

Beschreibung: Primarily released by the conversion of primary fossil energy sources, anthropogenic greenhouse gas emissions influence global warming fundamentally. Since they enable increasing the share of sustainable energy sources in the energy supply and reducing greenhouse gas emissions through targeted integration, power-to-X technologies promise to be an important element of compliance with impending regulations and laws. VDI 4663 guideline for strategically optimizing (technical) processes applies the physical optimum, a promising performance indicator for a unified, time-independent, and structured evaluation of power-to-X technologies that defines an operation under physically optimal conditions as a limit value. This study applies VDI 4663 to a power-to-X system and evaluates different components. It specifically examines current power-to-gas applications, the physical optimum as a limit-oriented indicator and its application to complex processes, the physically optimal operation of electrolysis and methanation, heat transfer as a critical component of methanation, the evaluation of a heat exchanger based on the physical optimum, and targeted process optimization based on VDI 4663. The outcome is an energy index for the evaluation of a heat exchanger, factoring in its structural design. The physical optimum of electrolysis and methanation developed here can also be employed as the basis for targeted optimization. This study serves as a basis for the evaluation of other power-to-X systems and introduces the application of VDI 4663. Additionally, the applicability of the physical optimum to chemistry-based processes is validated.

Beschreibung: Increasing concerns about sustainability and energy conservation, coupled with the proliferation of incentives in the EU to achieve energy savings, suggest that significant improvements in energy efficiency should be realized. A policy measure that should have a direct impact on energy savings is the replacement of incandescent and halogen light bulbs by more efficient lighting technologies, which was implemented in 2009. Due to the lack of detailed data, it is not feasible to measure the effect of energy-efficient improvements on electricity consumption at the aggregate level using a bottom-up approach. To overcome this limitation, this paper analyzes hourly electricity demand in a very specific period of the day: the transition from day to night. In this short period, it is plausible that lighting is the main driver of changes in electricity demand, thus making it possible to estimate the increase in electricity consumption when lights are switched on and to analyze the effects of higher energy efficiency in lighting, if any. The results of the analysis for Spain show that during the periods 2009–2011 and 2015–2016, an estimated energy savings of 251 GWh can be attributed to a reduction in the magnitude of the lighting effect, which accounts for 20.3% of the observed decrease in electricity consumption during these two periods.

Beschreibung: The urban climate and outdoor air quality of cities that have a positive thermal balance depending on the thermal consumptions of buildings cause an increase of the urban heat island and global warming effects. The aim of this work has been to develop an energy balance using the energy consumption data of the district heating network. The here presented engineering energy model is at a neighborhood scale, and the energy-use results have been obtained from a heat balance of residential buildings, by means of a quasi-steady state method, on a monthly basis. The modeling approach also considers the characteristics of the urban context that may have a significant effect on its energy performance. The model includes a number of urban variables, such as solar exposition and thermal radiation lost to the sky of the built environment. This methodology was applied to thirty-three 1 km × 1 km meshes in the city of Turin, using the monthly energy consumption data of three consecutive heating seasons. The results showed that the model is accurate for old built areas; the average error is 10% for buildings constructed before 1970, while the error reaches 20% for newer buildings. The importance and originality of this study are related to the fact that the energy balance is applied at neighborhood scale and urban parameters are introduced with the support of a GIS tool. The resulting engineering models can be applied as a decision support tool for citizens, public administrations, and policy makers to evaluate the distribution of energy consumptions and the relative GHG emissions to promote a more sustainable urban environment. Future researches will be carried out with the aim of introducing other urban variables into the model, such as the canyon effect and the presence of vegetation.

Beschreibung: The building sector is a large energy consumer and is responsible for high CO2 emissions; hence, improving the energy performance of buildings is vital. Building renovations open opportunities to improve their energy performance. Building professionals and other actors in the early phase of renovations decide what energy efficiency and saving measures will be implemented. Their role is studied here from a middle-out perspective (MOP), investigating the different actors’ agency and capacity. Agency refers here to an interest in and a willingness to implement energy efficiency and saving measures, and capacity refers to the ability to implement such measures. Higher agency and capacity are said to increase the realisation of the planned energy efficiency and saving measures. The data was gathered during three planning and design phases of renovation projects of a municipal housing company in a middle-sized Swedish town. A case study was conducted which is based on semi-structured interviews with actors from the planning and design phase of the renovations, as well as participant observations and a document analysis. The levels of agency and capacity of professionals in the middle of a project’s planning and design phase are investigated thoroughly, but the here defined top and bottom levels are also in focus. The analysis shows that a mismatch in agency and capacity on the different levels hindered the uptake of energy efficiency and saving measures in the planning and design of the renovation projects.

Beschreibung: Informational failures frequently lead consumers to make non-optimal energy-efficient purchasing decisions. Energy efficiency labels seek to influence consumer behaviour at the point of sale by reducing informational failures regarding energy efficiency. However, several informational and behavioural factors contribute to the energy efficiency gap and could render label-oriented policies useless. The purchasing decision model of Allcott and Greenstone (The Journal of Economic Perspectives, 26, 3–28, 2012) is used here to explore the different factors that influence purchasing decisions and understand (i) the importance of energy consumption compared to other attributes; (ii) how consumers weight energy savings and (iii) what other benefits and costs influence the purchase of energy-efficient goods. The analysis reported here is based on qualitative research methods and is conducted in the household and service sectors (the accommodation sector and private service companies), for appliances, heating and cooling systems and cars in Spain. Results show that (i) there is still an informational gap regarding energy labels and (ii) bounded rationality and end-user behaviour are important limiting factors for the purchase of energy-efficient goods in Spain.

Beschreibung: Contemporary packages of housing retrofit equipment are based on models of expected energy savings with regard to globally standardized thermal comfort levels. Previous research shows that the energy savings realised after a housing retrofit is substantially lower than expected. Attempts to reduce energy demand by physical re-design, utilising technical standards for thermal comfort as well as financial incentives, tend to ignore the role of retrofit interventions in the construction of everyday practices of thermal comfort making. Thermal comfort practices of heating, cooling and ventilation are moderated by specific householders’ motivations which constitute ‘wants’ and emerging ‘needs’ in the interaction with the housing retrofit equipment. This paper proposes that the interactions between the retrofitted buildings and the householders are the sum of material affordances, as signified by the design of the housing equipment on the one hand, and the practical affordances in practices-as-performances on the other. The study presents comfort practices in relation to recently retrofitted low-income housing estates in Beijing, Mianyang (Sichuan province, South-west China) and Amsterdam on the basis of 50 qualitative interviews with householders in each city. The paper concludes that the expected energy saving is counteracted by a poor match between conventional retrofit packages and householders’ considerations about their thermal comfort. To better reduce energy demand and to mitigate energy poverty, retrofit packages should provide adaptive thermal comfort as preferred by householders, rather than fixed or tightly specified thermal comfort. Such a perspective may support a more flexible and inclusive use of housing equipment as part of retrofit programs.

Beschreibung: The UK introduced carbon budgets in 2008, with an aim to reduce greenhouse gases by 80% by 2050 compared with the 1990 levels. It has been argued that the 2015 Paris Agreement on limiting the global average temperature rise to ‘well below 2° C’ requires deeper and more rapid emission reductions than the current UK targets. Household energy consumption accounts for almost a third of total UK CO2 emissions in recent years. This paper explores drivers of high energy consumption in domestic buildings from a sociological practice perspective and through a lens of dominant meanings of ‘home’. Whilst the practice approach and meanings of home have been explored separately in the literature to understand household energy consumption, this paper adds new findings on the interaction between the meanings of home and the elements of practices. Results show the dominant meaning of home differs between householders; this in turn affects the materials and procedures of energy-consuming practices. For instance, if ‘home’ means ‘hospitality’, this changes the standard of comfort and convenience people perceive at home. Understanding how practices and meanings of the home intersect, provides new, much needed insights that could support policy change commensurate with more rapidly reducing CO2 emissions from domestic energy consumption.

Beschreibung: Homeowners are identified as a group in society that could change their energy behaviour towards greater energy efficiency and use of non-fossil fuels. External local energy advisors, who provide knowledge, motivation and service, can influence their decisions and thereby increase energy efficiency and dissemination of non-fossil fuels. In Sweden, the energy advice system has recently been reformed and this paper investigates this reform and analyses its early effects. The aim is to analyse how energy advisors manage the reform and how they work as middle actors to increase energy efficiency and non-fossil fuel use among homeowners. We use the theoretical framework of middle actors in the middle-out perspective together with the theory of institutional logics to analyse the case of the energy advisor reform. This qualitative analysis contributes to the discussion of energy advisors by focusing on the relevance of organizational structures and logics for their possibilities to influence homeowners’ energy practices. The reform has introduced a governance and New Public Management logic that runs parallel with the former energy advice logic, guiding the advisors’ work practice. The results show that the reform potentially has increased the energy advisors’ ability to act as middle actors. However, there are organizational practices following the reform, which greatly constrain the advisors’ abilities as middle actors. One conclusion is that the advisors are in need of more guidance from the Energy Agency to be able to perform more successful work.