Pilot Study. Climate change impacts on the hydropower sector in Trentino, Italy

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1 T H E M AT I C C E N T R E l D r o u g h t, Wa t e r a n d C o a s t s Pilot Study Climate change impacts on the hydropower sector in Trentino, Italy

2 Three pilot studies were carried out under the OrientGate Thematic Centre on Drought, Water and Coasts: on climate change adaptation in the new water regime in Puglia Region, Italy (Pilot Study 3); on the effects of climate change on the wetland ecosystems of Attica Region, Greece (Pilot Study 4); and on water resources and the use of hydroelectricity in the Autonomous Province of Trento, Italy (Pilot Study 5).

3 Establishing the research team The Autonomous Province of Trento contributed to the OrientGate project with a study of the impacts of climate change on water resources, with particular reference to the use of water for the production of hydroelectric power to meet the needs of the whole of the province. The study was carried out by the Civil Defence Department in collaboration with the Agency for Energy and Water Resources and the Department of Civil, Environmental and Mechanical Engineering of the University of Trento. Study sites Given the complexity of the area, the research was concentrated in two sample river basins: the basin of the Noce, where there are important glacial areas and various large plants exploiting hydroelectric power; and the basin of the Brenta, where there are neither glacial areas nor hydroelectric plants with large reservoirs. Objectives The study was designed to identify and analyse indicators of the availability for water resources, both in natural conditions and in the event of anthropogenic exploitation, focusing in particular on the potential for hydroelectric power production. The study aimed to evaluate areas of vulnerability in order to achieve the sustainable use of hydropower in the context of climate change and the diversified use of water resources. The ultimate goal was to propose criteria for improving policies related to the development of hydroelectric power and to incorporate the results when drawing up and establishing priorities for area planning. Stakeholder involvement As the project addresses questions of a wide-ranging and multidisciplinary nature, during the development of the pilot study there was a direct exchange of ideas with key stakeholders, including technical staff in the public administration, climate researchers, university professors, scientists and politicians. Taking their contributions into consideration, the project content was adjusted in order to ensure that the output responds to the real needs of those who will make use of it.

4 Climate expectations The climate scenarios used in the study are based on regional-scale simulations produced by the Centro Euro Mediterraneo sui Cambiamenti Climatici. Two possible future scenarios in relation to the concentration of atmospheric greenhouse gases (GHGs) were chosen from the four so-called representative concentration pathways adopted by the Intergovernmental Panel on Climate Change in its Fifth Assessment Report. The first involves the stabilisation of GHGs (RCP4.5), while the second assumes a continuous increase (RCP8.5). According to the scenarios, a continuing rise in temperatures can be predicted for Trento, both annual and seasonal, with a far more marked increase in summer, in both the short term ( ) and the longer term ( ). As far as precipitation is concerned, there is expected to be a limited annual decrease, with greater variability over the seasons. A significant decrease is expected in summer, and to some extent also in spring, while an increase is predicted in winter. Hydrological scenarios In order to develop reliable scenarios, climatic and hydrological modelling had to be combined. Hydrological modelling makes it possible to reconstruct runoff towards surface watercourses starting from meteorological forcing, measured on the ground or made available through weather simulation models. The GEOTRANSF hydrological model was adopted for use in the study. Developed by the University of Trento s Department of Civil, Environmental and Mechanical Engineering, the model was calibrated and validated using historic datasets of streamflow measurements, starting from recorded temperature and precipitation datasets. The model was then applied to climatic forcing, with reference to future scenarios (RCP4.5 and RCP8.5) for the periods and

5 Impacts on water resources and hydroelectricity The most evident impact of climate change in the future is related to seasonal variations in the water cycle. Warmer summers with less rain could mean more significant episodes of water scarcity. The rise in temperatures will encourage the progressive depletion of glaciers and will bring forward the beginning of the snow melting period earlier in the spring. In autumn and winter more rain is expected, while snow will accumulate at higher altitudes due to higher temperatures. The greater availability of water in the winter will not, however, compensate for the significant decrease expected in the summer, thus there will be a slight decrease in annual runoff. This will have an impact on water resources used for hydroelectric power generation, and a slight fall in withdrawal volumes is estimated over the year. Putting results into practice The hydropower sector faces important climate-related challenges that threaten its sustainability. While the drive to exploit alternative energy sources has led to a significant increase in the number of small hydropower plants, the uncontrolled development of this energy source can have a huge impact on ecosystems and lead to greater conflicts between sectors competing for water resources. The pilot study evaluated the impacts of climate change, particularly in terms of the seasonal availability of water and changes that will exacerbate problems related to the management of water resources in competing sectors, such as drinking water supply, agriculture and hydropower, especially in the summer. Although more research is needed, the pilot study results have yielded valuable input that allows policy makers to promote the ecologically sustainable management of water resources in the future.

6 Pilot Study 1: Adapted forest management at LTER Zöbelboden Pilot Study 2: Climate change adaptation measures in Romanian agriculture Pilot Study 3: Climate change adaptation in the new water regime in Puglia Region, Italy Pilot Study 4: Effects of climate change on the wetland ecosystems of Attica Region, Greece 3 4 Pilot Study 5: Water resources and the use of hydroelectricity, Italy Pilot Study 6: Vulnerability assessment in Budapest and Veszprém Contacts Lead partner, project coordinator Antonio Navarra Euro-Mediterranean Centre on Climate Change (CMCC) l Via Augusto Imperatore 16 l Lecce, Italy l antonio.navarra@cmcc.it l Giulia Galluccio Euro-Mediterranean Centre on Climate Change (CMCC) l Corso Magenta 63 l Milan l Italy l Tel.: (39-02) l giulia.galluccio@cmcc.it l Pilot study 5 coordinator Roberto Barbiero Autonomous Province of Trento l Piazza Dante 15 l Trento l Italy l Tel.: ( ) l roberto.barbiero@provincia.tn.it l Pilot study 5 scientific coordinator Serenella Saibanti Autonomous Province of Trento l Piazza Dante 15 l Trento l Italy l Tel.: ( ) l serenella.saibanti@provincia.tn.it l