In 2008, the UK Government enforced the target to reduce the UK carbon account for the year 2050 to at least 80% less than the 1990 baseline. In order to meet this ambitious target it is widely thought that the UK energy future should be ‘electrified’ as a suite of low carbon generation technologies provide ever increasing proportions of electricity supply. This work has identified and investigated two technologies that could make significant contributions to low carbon power supply in the UK; that of industrial combined heat and power, CHP, and tidal power. Life cycle case studies were completed on an existing UK CHP plant and the Severn Barrage scheme as it was proposed until 2010. The Severn Barrage assessment has shown that the lifetime environmental impact is dominated by the operation stage. This is contrary to previously published studies, which have underestimated (Parsons Brinckerhoff Ltd; Black and Veatch Ltd; 2010)(Roberts 1982)(Spevack, Jones and Hammond 2011) or even ignored (Black & Veatch 2007)(Woollcombe-Adams, Watson and Shaw 2009)the contribution from this life stage. Furthermore, the results have demonstrated that the impact intensity of power from the Barrage is almost entirely reliant on that of the National Grid mix which provides the operational power required. It has been shown a large improvement to the impact of the operation stage can be made by removing the electricity demand for ‘flood pumping’. However, even without ‘flood pumping’, the impact of the power demand for plant operation will dominate. Hence the greatest improvements to the schemes lifetime impact can be made via the National Grid mix itself. The industrial CHP assessment has shown that there are large impact savings available from widespread implementation against the current and the baseline National Grid mixes. However, even if it is assumed that units are exclusively bio-gas fuelled, the carbon intensity of the power generated is very likely to exceed that of the low carbon Grid mix by 2050. The discussion shows that the interactive roles that these two technologies could play, with each other and the evolving Grid mix, on the pathway to 2050 is, however, more complex than simply considering the isolated impact intensity. The commissioning of the Severn Barrage could mark the point at which the carbon intensity of the National Grid falls below that of CHP. However because the carbon intensity of the plant is reliant on the national power supply, it is argued that further CHP implementation should only be stopped if there is a suitable low carbon and low impact alternative that can fill the capacity gap. This thesis concludes that to fear that today’s CHP schemes could represent a technology ‘lock-in’ in the long term future is to underestimate the role the technology has in the current and more short term future Grid mix. The work presented demonstrates the importance of life cycle thinking in the development of a low impact energy strategy. The discussion has also shown the importance of scenarios in assessing the requirements for such an ambitious change. The pursuit of change implies that the future is necessarily dynamic. The work has illustrated that scenario thinking allows exploration of potential strategy decisions and hence, is essential to having confidence in the decisions made.

Le développement du quartier comme échelle d’un développement urbain plus durable s’inscrit dans une période de prise de conscience liée au changement climatique pour lequel l’Union Européenne a mise en place une politique de transition énergétique. Actuellement, les écoquartiers se structurent autour de deux points clés au niveau énergétique : l’efficacité énergétique et l’approvisionnement énergétique. L’efficacité énergétique qui englobe la performance énergétique du bâtiment et la maitrise de la demande énergétique est le fer de lance des politiques de transition énergétique locale existante. A l’opposé, l’approvisionnement énergétique bas carbone ne semble pas avoir encore atteint une maturité suffisante pour être réalisée en totalité à l’échelle du quartier. Néanmoins, l’analyse des projets d’écoquartiers montre l’intérêt croissant porté à la création d’une offre énergétique bas carbone employant les ressources locales. Cet intérêt traduit, notamment, la volonté de certains acteurs locaux d’atteindre un certain degré d’autonomie énergétique. Afin d’envisager le quartier comme une échelle pertinente pour l’approvisionnement énergétique bas carbone, il est nécessaire d’analyser les conditions technico-économiques et institutionnelles à mettre en œuvre. Elle révèle le besoin d’un changement de paradigme dans la structuration des systèmes énergétiques passant de systèmes centralisés à des systèmes décentralisés. Or, ce nouveau paradigme est conditionné par la maturité technico-économique des infrastructures pouvant être installées dans le quartier et par la capacité à trouver un modèle d’affaire viable rendant l’investissement rentable à cette échelle. D’un point de vue institutionnel, il provoque une modification des relations entre les acteurs utilisant les vecteurs énergétiques étudiés (électricité et chaleur). L’essor de nouveaux profils de production avec le développement des énergies renouvelables et l’émergence de nouveaux profils de consommateurs devenant des producteurs modifie la chaîne de valeur énergétique et oblige à garantir la flexibilité des systèmes énergétiques pour garantir leur bon fonctionnement. Pour tenter d’apporter un éclairage sur les possibles formes que pourraient prendre ces relations, une démarche méthodologique reposant sur la construction d’idéal-types a été réalisé. Elle fait apparaître le besoin d’un nouvel acteur, le gestionnaire de l’énergie, pour garantir le bon fonctionnement des systèmes énergétiques installés dans les quartiers. / The development of the neighborhood as a scale of a more sustainable urban development takes part in a period of awareness linked to climate change for which the European Union has implemented an energy transition policy. In this context, the eco-neighborhoods are structured around two key points in terms of energy: energy efficiency and energy supply. Energy efficiency, which encompasses the energy performance of buildings and the control of energy demand, is the spearhead of existing local energy transition policies. In contrast, the low-carbon energy supply does not seem to have reached sufficient maturity to be fully implemented at the neighborhood level. Nevertheless, the analysis of eco-district projects shows the growing interest in the creation of a low carbon energy supply using local resources. This interest reflects, in particular, the willingness of some local actors to reach a degree of energy autonomy. In order to consider the neighborhood as a relevant scale for low-carbon energy supply, it is necessary to analyze the technical-economic and institutional conditions to be implemented. It reveals the need for a paradigm shift in the structuring of energy systems from centralized to decentralized systems. However, this new paradigm is conditioned by the technical and economic maturity of the infrastructures that can be installed in the district and by the ability to find a viable business model making the investment profitable on this scale. For the institutional part, it causes a modification of the relations between the actors using the energetic vectors studied (electricity and heat). The rise of new production profiles with the development of renewable energies and the emergence of new consumer profiles becoming producers, alters the energy value chain and makes it necessary to guarantee the flexibility of energy systems to ensure their correct functioning. To plan a different pathway that these relationships might take, a methodological approach based on the construction of the ideal-type was carried out. It shows the need for a new player, the energy manager, to ensure the proper functioning of the energy systems installed in the neighborhoods.

To reduce fossil fuel consumption and carbon emission in the building sector, renewable and low carbon energy technologies are integrated in building energy systems to supply all or part of the building energy demand. In this research, an optimal supervisory controller is designed to optimize the operational cost and the CO2 emission of the integrated energy systems. For this purpose, the building energy system is defined and its boundary, components (subsystems), inputs and outputs are identified. Then a mathematical model of the components is obtained. For mathematical modelling of the energy system, a unified modelling method is used. With this method, many different building energy systems can be modelled uniformly. Two approaches are used; multi-period optimization and hybrid model predictive control. In both approaches the optimization problem is deterministic, so that at each time step the energy consumption of the building, and the available renewable energy are perfectly predicted for the prediction horizon. The controller is simulated in three different applications. In the first application the controller is used for a system consisting of a micro-combined heat and power system with an auxiliary boiler and a hot water storage tank. In this application the controller reduces the operational cost and CO2 emission by 7.31 percent and 5.19 percent respectively, with respect to the heat led operation. In the second application the controller is used to control a farm electrification system consisting of PV panels, a diesel generator and a battery bank. In this application the operational cost with respect to the common load following strategy is reduced by 3.8 percent. In the third application the controller is used to control a hybrid off-grid power system consisting of PV panels, a battery bank, an electrolyzer, a hydrogen storage tank and a fuel cell. In this application the controller maximizes the total stored energies in the battery bank and the hydrogen storage tank.

This Master Thesis deals with the issue of transition to low-carbon energy in the European Union, with an example of the United Kingdom of Great Britain and Northern Ireland. The topic is divided into three parts. Firstly, the energy sector in the EU is described in the context of environmental targets, institutional framework, international Paris agreement and electricity price factors. Secondly, the British concept of transition to low-carbon energy is described, following a similar line from the first chapter. Last but not least, the third section uses the data and information provided in the first two sections to create a complex picture. Compatibility of the British concept with the EU policies is discussed, furthermore the meaning of Paris agreement for the British model is described, then the consequences of the British concept on the electricity prices are shown, finally the challenges for the British energy sector are considered. The main contribution of this thesis is statistical comparison of energy in the EU and UK and finding the connection between international events (Paris agreement), regional priorities (EU), national political representation and national interest groups in terms of creating energy policy in the UK.

Die Dissertation beleuchtet die dringende Notwendigkeit, Maßnahmen zu ergreifen, um den Druck auf die Ressourcen der Erde zu mindern und nachhaltige Bedingungen für gegenwärtige und künftige Generationen zu schaffen. Zwei zentrale Strategien werden diskutiert: Die Dekarbonisierung von Energiesystemen und die Reduktion der Emissionen von Haushalten. Diese Strategien sind eng mit Fragen von Gerechtigkeit verbunden, sowohl im Zusammenhang mit einer gerechten Energiewende als auch in der Emissionsminderung von Haushalten. Die Dissertation besteht aus vier Artikeln, die diese Themen vertiefen. Die erste untersucht den Kohleausstieg in europäischen Regionen und die Wahrnehmung der Energiewende durch die davon betroffenen Menschen. Die nächsten beiden untersuchen die Emissionsreduktion auf Haushaltsebene, wobei die sozialen Realitäten der Emittenten analysiert werden, um Reduktionspotenziale zu identifizieren. Die vierte Publikation bietet einen historischen Überblick über Energiekonsummuster und zeigt vergangene und bestehenden Ungleichheiten auf. Die Ergebnisse zeigen, dass die Klimakrise nur unter Berücksichtigung von Ungleichheiten und Ungerechtigkeiten verstanden und angegangen werden kann. Lösungen müssen darauf abzielen, weitere Ungerechtigkeiten zu vermeiden. Die Ergebnisse der Dissertation bieten unter anderem wertvolle Erkenntnisse für Entscheidungsträger auf verschiedenen Ebenen, um eine gerechte Transformation zu klimaneutralen Gesellschaften voranzutreiben. Es wird jedoch betont, dass weitere Forschung in diesen Bereichen, einschließlich anderer fossiler Energieträger und betroffener Regionen, sowie unterschiedlicher Lebensstile, entscheidend ist, um effektive Instrumente zur Unterstützung nachhaltiger Praktiken zu entwickeln. / The dissertation underscores the urgent need to address the strain human activities place on the Earth system, emphasizing the necessity for sustainable solutions to ensure the well-being of current and future generations. Mitigating the impacts of the climate crisis requires significant reductions in greenhouse gas emissions, prompting a closer examination of their sources and contributors. Two primary strategies are proposed: decarbonizing energy systems and reducing household emissions. However, discussions surrounding these strategies often intersect with considerations of justice, highlighting the complex social dimensions of addressing climate change. The dissertation comprises four papers that delve into these issues. The first explores the transition away from coal in European regions, assessing perceptions of justice among affected actors. The subsequent publications focus on emissions reduction at the household level, analyzing social realities and identifying potential avenues for mitigation. The final publication provides a historical perspective on energy consumption patterns, emphasizing past and contemporary societal inequalities. Findings indicate disparities in emissions across households and individuals, necessitating urgent action to reduce per capita emissions. Moreover, sociological frameworks are employed to better understand the ecological dimensions of emissions, revealing complex relationships between social classes and environmental impact. While efforts to combat the climate crisis must prioritize justice and equity, the dissertation also underscores the need for further research. This includes examining alternative energy sources, regions disproportionately affected by climate change, as well as diverse lifestyles. Such research will be essential for developing effective strategies to support sustainable practices and address the complex social dynamics of climate action.