Assessing the potential to strengthen the resilience of the Swiss hydropower sector based on understanding the role of weather regimes in a changing climate
Mitigating climate change requires a major transformation of energy production with an increasing shift from fossil fuels to renewable energy sources, such as wind and hydropower. These, however, are strongly affected by local weather conditions and their future potential might be influenced by clim...
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
ETH Zurich
2021
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/20.500.11850/497310 https://doi.org/10.3929/ethz-b-000497310 |
| Summary: | Mitigating climate change requires a major transformation of energy production with an increasing shift from fossil fuels to renewable energy sources, such as wind and hydropower. These, however, are strongly affected by local weather conditions and their future potential might be influenced by climate change. Thus, it is essential for decision-makers in the energy sector to integrate information about climate change in their long-term strategic decisions. These types of decisions are, for instance, required for Switzerland’s upcoming concession renewals, i.e., contracts that regulate how hydropower companies are allowed to use the water owned by local government for power generation over decades. The high-level goal of this thesis is to integrate a specific tool from atmospheric science, so-called weather regimes (WRs), with the strategic decision-making of a stakeholder from Swiss hydropower industry. To this end, we engage directly with a Swiss hydropower company throughout the research process. Together we address three main topics. (1)We develop an understanding of the relationships between Swiss hydropower generation and the large-scale atmospheric flow represented by WRs. (2) Based on both an extensive literature review and our own experience gained in the present project, we propose an engagement framework and practical recommendations on how to implement a transdisciplinary (TD) collaboration with an industry partner. (3)We quantify the role that WRs play for weather parameters in a changing climate, and discuss potential implications of this analysis for the stakeholder’s decision making. Chapter 2 is dedicated to improving our understanding of how WRs have affected surface weather in Switzerland and Europe and hence Swiss hydropower generation in recent years. We present exploratory analyses investigating (i) whether precipitation in Switzerland is similar in all WRs and at all times in a WR’s life cycle, (ii) how the seven North Atlantic European WRs modulate the spatial pattern of precipitation and wind in Switzerland and Europe, and (iii) whether Swiss hydropower generation systematically increases or decreases during specific WRs. Mean daily precipitation over Switzerland is not strongly linked to weather regime type and duration. However, the spatial distribution of precipitation across Switzerland and Europe exhibits a distinct WR-specific dependency, in particular in the cold season. Finally, we find that the link between Swiss hydropower generation and the active WR is only moderate. Reasons for this moderate link can be numerous other factors that influence Swiss hydropower generation; the large WR domain that captures less of the Switzerland-specific atmospheric flow variability; and the limited dataset used for the presented analyses. Nevertheless, these analyses provide an initial overview of the complexities of how weather and climate influence (future) hydropower generation, provoking new perspectives on how weather matters for Swiss hydropower. Chapter 3 addresses the following question: How can climate scientists practically implement a transdisciplinary (TD) collaboration with an industry partner to reduce the gap between climate science and decision-making in industry? We propose a novel engagement framework that provides guidance to this question. The framework conceptualizes engagement through scientists and stakeholders overlapping spheres of interests, and it offers the opportunity to explore and widen their overlap as a common space of interests. We present a case study where we apply this framework to our collaboration with the Swiss hydropower company, again using the concept of weather regimes. This case study leads to four practical recommendations for using the proposed engagement framework effectively: (1) Secure an anchor person at management level of the decision-making entity; (2) Be prepared to invest time into triggering and maintaining active engagement by all collaborators; (3) From the start, communicate the open nature of insights and solutions from the engagement process; (4) Be aware that you are working in a field of tension due to a range of motivations, methods, and goals of the individuals involved in the TD collaboration. The engagement framework and the practical recommendations are particularly beneficial for climate scientists who are not yet familiar with TD collaborations. Chapter 4 aims at improving our understanding of the representation of WRs in climate models and how they are affected by climate change. Using a seven-category all-season WR classification for the North Atlantic and European region as a means to represent important aspects of the variability of the large-scale atmospheric dynamics in this region, we present the first year-round evaluation of WRs in a climate model and associated changes due to climate change. We investigate (i) whether the frequency of occurrence of these regimes observed in reanalysis is captured by historical climate simulations, (ii) whether the frequency of occurrence is affected by climate change, (iii) whether precipitation associated with those WRs is affected by climate change, and (iv) to what degree changes in the frequency of WRs explain the overall climate change signal in precipitation. We use output from historical and end-of-the-century (RCP8.5) Community Earth System Model (CESM) large ensemble simulations to determine the frequency of occurrence of the seven WRs and their associated precipitation patterns in both historical and end-of-the-century climate conditions. As in the re-analysis data from the European Centre for Medium-RangeWeather Forecasts (ECMWF), ERA-Interim, the WRs in CESM explain approximately 80% of the year-round variability in geopotential height at 500 hPa in the considered North Atlantic and European region. Climate change causes an annual increase in the frequency of the Atlantic Trough (AT) and European Blocking (EuBL) regimes, and a decrease of the Greenland Blocking (GL) regime. The contribution of these WR frequency changes to the climate change signal of surface precipitation is however surprisingly small. These findings indicate that climate change imposes subtle changes on the large-scale flow over the North-Atlantic and Europe as revealed by the frequency changes of certain WRs. However, the precipitation patterns associated with the WRs are relatively similar and also affected by climate change in a similar fashion. Together, this implies that precipitation in Europe most likely changes in the future due to an overall warming (all WRs get wetter) and due to subtle changes in the WR frequencies, but not due to strongly altered precipitation dynamics in a given large-scale flow configuration nor due to a substantial increase or decrease in occurrence of a specific WR. The TD engagement and WR analyses provide valuable insight for decision-makers and scientists alike. Active engagement with the Swiss hydropower company guided methodological choices and research questions while providing direct feedback and triggering reflection on scientific results. This in-depth TD engagement process allowed hydropower decision-makers to benefit from complex scientific expertise they would otherwise not have had access to. Additionally, it highlighted that in the long-term consideration around hydropower generation, climate change is one of the most projectable elements. Thus, decision-makers were encouraged to consider how much could be gained by integrating climate knowledge into their long-term strategic decisions. Future work is encouraged to investigate the role of atmospheric flow dynamics for the energy sector, with more renewable energy sources (solar, wind, and hydropower), integrating multiple energy stakeholders across multiple countries (including state-owned and private firms), and employing alternative statistical analyses and machine learning to analyze additional data that arises from the aforementioned suggestion of increasing included energy sources and stakeholders. |
|---|