1. Introduction
1.1. Motivation
The World Commission on Environment and Development has stated that sustainable develop-ment:
“[…] meets the needs of the present without compromising the ability of future generations to meet their own needs. […] sustainable development is not a fixed state of harmony, but rather a process of change in which the exploitation of resources, the direction of investments, the ori-entation of technological development, and institutional change are made consistent with fu-ture as well as present needs.” [1]
Sustainable development is related to the energy sector because finite natural resources are exploited for the provision of energy services, large investments are made in energy
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ture which is operated over generations, and energy technologies are developed today with the purpose of satisfying future energy demands. The importance of the energy sector for sustaina-ble development has recently been emphasised by the United Nations’ (UN) formulation of the Sustainable Development Goals (SDG) which envisages a world “where there is universal access to affordable, reliable and sustainable energy” [2]. Universal access to affordable, reliable and sustainable energy contributes to the overarching goals of ending poverty, protecting the planet, and ensuring prosperity for all.
The above-mentioned vision for the energy sector refers to the three dimensions, economy, so-ciety and environment, which have been used to operationalise the definition of sustainability by the World Commission on Environment and Development, for example in the course of the initiative of the International Atomic Energy Agency (IAEA) for developing a set of energy indi-cators for sustainable development in collaboration with the United Nations Department of Economic and Social Affairs (UNDESA), the International Energy Agency (IEA), Eurostat and the European Environment Agency (EEA) [3]. These three dimensions of sustainability can be fur-ther differentiated into a set of criteria, which represents relevant areas of concern. Such a crite-ria set for the energy sector was for example provided by Hirschberg et al. [4] and is presented in Figure 1. The performance of energy technologies and systems regarding the sustainability criteria can be measured with specific qualitative and quantitative indicators for the current status as well as for future progress in the direction of sustainable development.
Figure 1: Main environmental, economic and social criteria for sustainability assessment [4]
1.2. Research questions ______________________________________________________________________________________________________________
3 Today’s energy systems do not reach the SDG in the field of energy. 1.3 billion people have no access to electricity [5], and the reliance on non-commercial forms of energy (e.g. fuel wood and charcoal) and the lack of clean cooking fuels leads to human health damages and degradation of (local) ecosystems. Currently, 81% of the global primary energy supply is provided by fossil fuels [6]. Their combustion not only contributes to the climate change, but also to the depletion of finite natural resources and to human health and ecosystem damages due to air pollution and wastes. Every step in the relevant energy chains, from the extraction of the energy resource to transport, storage and end-use of the energy carrier, requires materials and fuels, produces emissions and wastes, and contains accident risks. Renewable energies can be associated with high energy supply costs, they can lead to intermittency in energy supply, and their decentral-ised installations can lead to societal conflicts. Nuclear energy use creates long-living radioac-tive waste and bears the risk of proliferation of radioacradioac-tive materials for nuclear weapons.
As all energy technologies and energy systems have different strengths and weaknesses regard-ing sustainability criteria such as the ones listed in Figure 1, there is no sregard-ingle energy technology or system which is completely “affordable, reliable and sustainable”. The world’s energy systems are diverse not only regarding the type and technical status of the applied conversion technolo-gies, but also regarding the type of energy resources used and the sectoral and technology mixes on the demand side. Therefore, developments are expected to be regionally diverse and there is no “one-size-fits-all” solution for sustainable development in the energy sector.
1.2. Research questions
Sustainable development of energy systems in the direction of the SDG in the field of energy requires the investigation of multiple criteria on the one hand and long-term strategic planning due to the large investments and the long lifetimes of the energy infrastructure on the other hand. This applies on the level of companies in the energy sector but particularly on the level of governments where policy-makers set the boundary conditions for the transformation to more sustainable energy systems. Decision-making in the context of energy system transformation can be supported with modelling approaches, which consider the long-term energy system per-spective and multiple sustainability criteria. This leads to the research questions of this thesis:
How can long-term developments of the energy technologies and the energy systems they are embedded in be analysed?
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How can the sustainability of the energy systems be investigated taking into account multi-ple criteria?
Which combined methods can be applied for long-term multi-criteria sustainability analysis of energy systems?
Which approaches to data processing and changes to the existing approaches are required for the implementation of the combined methods?
How does the future Swiss energy system perform with respect to a set of sustainability criteria under different technological and political boundary conditions?
What are the global and regional sustainability trends in different long-term transformation pathways of the global energy system?
1.3. Structure of the thesis
Chapter 2 gives an overview of methods and combined methods for the analysis of the long-term development of energy systems and their sustainability. The four combined methods de-scribed in Chapter 2 are then applied in separate case studies, which are presented in Chapters 3 to 6. In Chapter 3, three energy system pathways for Switzerland are analysed with a focus on the sustainability impacts of the Swiss climate policy and the availability of the Carbon Capture and Storage (CCS) technologies. In Chapter 4, the long-term sustainability of the World Energy Scenarios of the World Energy Council (WEC) is addressed from a global as well as from select-ed regional perspectives. In Chapter 5, the external costs from human health damages due to air pollution are quantified for the World Energy Scenarios and benchmarked with the external costs of greenhouse gas (GHG) emissions, the energy system costs and the Gross Domestic Product (GDP). In Chapter 6, three different sustainability indicators are endogenised in the energy system modelling framework. Based on the optimisation of these three policy objectives, corresponding global energy system pathways are quantified. The thesis concludes with a summary of the insights regarding the research questions and an outlook for further research.
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