Quantification of electrical load flexibility offered by an air to water heat pump equipped single-family residential building in Sweden

Heat pumps are widely used in Swedish single-family houses for space and water heating applications, of which the most common is air-to-water heat pumps. Today, there is an increase in the variability and uncertainty of electricity production due to an increment in the share of electricity generation by intermittent energy sources. Hence, as opposed to the conventional power system operation, there is variability and uncertainty in electricity consumption and production. One possible way of addressing the challenge of balancing the power system is by using heat pumps as a flexibility resource. In this regard, this study quantifies the flexibility potential by developing and integrating a mathematical model of an air-to-water heat pump with the thermal model of a building with a standard way of space heating i.e., radiator heating. The result from this study will provide an estimate of flexibility levels from space heating, in terms of varying levels of reduced electricity consumption as a function of indoor temperature, during different outdoor ambient temperatures. Furthermore, the result of this study helps in employing suitable measures for demand-side-management to support the power system during severe problems

Energy Loss Savings Using Direct Current Distribution in a Residential Building with Solar Photovoltaic and Battery Storage

This work presents a comparison of alternating current (AC) and direct current (DC) distribution systems for a residential building equipped with solar photovoltaic (PV) generation and battery storage. Using measured PV and load data from a residential building in Sweden, the study evaluated the annual losses, PV utilization, and energy savings of the two topologies. The analysis considered the load-dependent efficiency characteristics of power electronic converters (PECs) and battery storage to account for variations in operating conditions. The results show that DC distribution, coupled with PV generation and battery storage, offered significant loss savings due to lower conversion losses than the AC case. Assuming fixed efficiency for conversion gave a 34% yearly loss discrepancy compared with the case of implementing load-dependent losses. The results also highlight the effect on annual system losses of adding PV and battery storage of varying sizes. A yearly loss reduction of 15.8% was achieved with DC operation for the studied residential building when adding PV and battery storage. Additionally, the analysis of daily and seasonal variations in performance revealed under what circumstances DC could outperform AC and how the magnitude of the savings could vary with time

The co-evolution of technological promises, modelling, policies and climate change targets

The nature and framing of climate targets in international politics has changed substantially since their early expressions in the 1980s. Here, we describe their evolution in five phases-from 'climate stabilization' to specific 'temperature outcomes'-co-evolving with wider climate politics and policy, modelling methods and scenarios, and technological promises (from nuclear power to carbon removal). We argue that this co-evolution has enabled policy prevarication, leaving mitigation poorly delivered, yet the technological promises often remain buried in the models used to inform policy. We conclude with a call to recognise and break this pattern to unleash more effective and just climate policy. This Perspective maps the history of climate targets and shows how the international goal of avoiding dangerous climate change has been reinterpreted in the light of new modelling methods and technological promises, ultimately enabling policy prevarication and limiting mitigation

Key Messages and Briefing Notes on Carbon Capture and Storage

The study investigated stakeholder perceptions of information on CCS - including those of science writers and journalists, policy makers and commercial organisations with an interest in CCS and specialists in science communication. Based upon these findings, a set of 14 Briefing Notes (each 2500 to 4000 words in length) were prepared and appropriate images and photographs selected to help explain the key concepts. The intended audience is science communicators, journalists, writers, students, interested members of the public and policy makers who need to know something about CCS in a relatively short time period

Clash of Geofutures and the Remaking of Planetary Order: Faultlines underlying Conflicts over Geoengineering Governance

Climate engineering (geoengineering) is rising up the global policy agenda, partly because international divisions pose deep challenges to collective climate mitigation. However, geoengineering is similarly subject to clashing interests, knowledge‐traditions and geopolitics. Modelling and technical assessments of geoengineering are facilitated by assumptions of a single global planner (or some as yet unspecified rational governance), but the practicality of international governance remains mostly speculative. Using evidence gathered from state delegates, climate activists and modellers, we reveal three underlying and clashing ‘geofutures’: an idealised understanding of governable geoengineering that abstracts from technical and political realities; a situated understanding of geoengineering emphasising power hierarchies in world order; and a pragmatist precautionary understanding emerging in spaces of negotiation such as UN Environment Assembly (UNEA). Set in the wider historical context of climate politics, the failure to agree even to a study of geoengineering at UNEA indicates underlying obstacles to global rules and institutions for geoengineering posed by divergent interests and underlying epistemic and political differences. Technology assessments should recognise that geoengineering will not be exempt from international fractures; that deployment of geoengineering through imposition is a serious risk; and that contestations over geofutures pertain, not only to climate policy, but also the future of planetary order

Coal and Climate Change

This overview adopts a critical social science perspective to examine the state of play and potential futures for coal in the context of climate change. It introduces key trends in coal consumption, production and trade, before appraising the relevant literature. Finding surprisingly little literature directly focussed on coal and climate change compared with related fields, it appraises existing work and highlights key areas for future work. In addition to established bodies of work on the situated politics of coal and the political economy of coal, new work calling for demand side policies to be supplemented with supply side policies highlights the increasing importance of how normative contestations drive debates over coal, suggesting that future work needs to engage not only much more directly with climate change as an issue, but particularly with the place of coal in a just transition. Because of coal’s mammoth contribution to climate change and the complex political economy which drives its production and consumption, it is likely that coal will remain at the centre of difficult questions about the relationship between climate action and development for some time

Efficiency of building related pump and fan operation - Application and system solutions

The electric energy use in Swedish non-industrial buildings is 71 TWh per year out of which 30 TWh per year is used for the operation of technical systems. A significant part of those 30 TWh/year is used for pump and fan operation. The Swedish parliament decided in 2009 on a national energy and climate plan. By the year 2050 the energy use per unit conditioned floor area in the Swedish building stock must be halved compared to the year of 1995. The objective of this thesis is to find means to reduce pump and fan energy in the non-industrial buildings. The aim is to find systems and components that can provide energy reduction in pump and fan systems by 50 %. In the thesis the current situation in non-industrial buildings regarding pump and fan systems has been described and the energy saving potentials, both at component and at system level, have been identified and discussed. Furthermore, the possibility of decentralized pump and fan systems has been examined. The calculated saving potential is 50 % and 40 % respectively for pump and fan operation in non-industrial buildings. This may be achieved by improving pump efficiency and specific fan power to state-of-the-art efficiency and recommended SFP values. System changes can also provide major additional energy savings in pump and fan operation. A decentralized pump heating system has been implemented in real life and results show a reduction of pump energy by 70 %. The theoretical parts of the thesis are supported by four case studies in real buildings and by three laboratory studies