Global change and the energy system: Assessing options and their impacts – the physical perspective

Project in the ExIni-II Cluster “Global Change and Globalization”
Research group 2: Global change & the energy system

Werner Aeschbach , Ulrich Platt and Tobias Tröndle, Institute of Environmental Physics.

The world´s energy system faces two types of constraints: Availability constraints of finite resources and environmental constraints of resource use. The latter reflect the global environmental feedbacks of the energy system, in particular with regard to global climate change, land, and water issues. These environmental constraints will necessitate a quantitative and qualitative shift in the energy sector, one of the key parts of the global economy. It is crucial that this transformation process is guided by reliable and objective knowledge about the various options.

The aim of this project is to assess the environmental consequences and the physical feasibility of some options that are expected to play a major role in the future energy system. The issue shall be tackled from two sides: 1) A general, "global" view of the energy options and 2) Detailed studies of physical aspects of selected technologies. The first part relies on our general expertise in physics and environmental issues to judge different options as well as on a system-analytical approach. The second part will be based on particular expertise present in environmental physics, e.g. to study trace gas emissions or impacts on aquatic systems.

In part I, an overview of the options and their main physical characteristics (e.g., greenhouse gas emissions, resource requirements (land, water, raw materials), energy return on investment (EROI), theoretical potential, waste products, etc.) shall be obtained mainly from a literature review. This knowledge will be integrated in a simple dynamic physical energy system model, enabling the assessment of long-term consequences of different scenarios (e.g., projecting CO2 emissions or resource requirements of different options if implemented according to prescribed paths). The main goal of this analysis is to provide a quantitative foundation for the identification of the most promising options (as well as those bound to fail), at least from the perspective of physical feasibility and environmental impacts. In part II, some specific options shall be investigated in more detail, to assess critical but poorly known aspects. For example, plans exist to perform measurements of trace gas emissions related to tar sand exploitation in Canada. This example of an unconventional fossil fuel resource shall also be studied with respect to water impacts and energy efficiency, in order to obtain a better understanding of the environmental limitations of this technology. Another controversial option are biofuels, where issues such as greenhouse gas emissions, water requirements, and net energy gains shall be further investigated. Available expertise in atmospheric physics can be used to assess the potential of integrated systems of weatherdependent renewable energy sources (wind and solar). Interaction with the Marsilius project on geo-engineering is also to be expected (e.g., with regard to carbon capture and storage, albedo effects of certain technologies, etc.). Close interaction with economic modeling is planned to assure that both physical and economic constraints are correctly accounted for in all models and scenarios. Expertise from the Geosciences will be needed in order to assess questions related to geo-resources, geological CO2 storage, as well as spatial and geopolitical impacts of different energy options.