• Energy Research

Replying to G. Wells et al. Nature Sustainability https://doi.org/10.1038/s41893-020-0544-3 (2020).

Payments for Environmental Services (PES) constitute an innovative economic intervention to counteract the global loss of biodiversity and ecosystem functions. In theory, some appealing features should enable PES to perform well in achieving conservation and welfare goals. In practice, outcomes depend on the interplay between context, design and implementation. Inspecting a new global dataset, we find that some PES design principles pre-identified in the social-science literature as desirable, such as spatial targeting and payment differentiation, are only partially being applied in practice. More importantly, the PES-defining principle of conditionality-monitoring compliance and sanctioning detected non-compliance-is seldom being implemented. Administrative ease, multiple non-environmental side objectives and social equity concerns may jointly help explain the reluctance to adopt more sophisticated, theoretically informed practices. However, by taking simplifying shortcuts in design and implementation, PES programmes may become less environmentally effective and efficient as economic incentives, thus underperforming their conservation potential.

Climate change is expected to affect hydropower generation by modifying river runoff and increasing reservoir evaporation. Anticipating the impact of climate change on hydropower generation is crucial to develop adaptation strategies and to efficiently plan a renewable energy transition. In this study, we assess the impact of climate change on hydropower generation using the Soil & Water Assessment Tool (SWAT) in Portuguese river basin with strategic importance, since it is responsible for 20% of the national hydropower generation. SWAT was calibrated against 6 reservoir flow-in and 1 river discharge, with a good agreement between simulated and observed values. Future climate projections were based on EURO-CORDEX climate simulations under RCP4.5 and 8.5 scenarios for 2031-2060 (short-term) and 2071-2100 (long-term), compared to 1976-2005. Results reveal that in the short-term, reservoir flow-in is expected to decrease up to 55% in the summer under RCP4.5, and up to 90% in the long-term under RCP8.5. Consequently, the hydropower plants may generate less 79 GWh per year in the short-term under RCP4.5, and less 272 GWh per year in the long-term under RCP8.5, which is equivalent to 11% and 38%, respectively, of the total electricity used in the study area in 2019. Our study shows that, at least in some regions, climate change can substantially reduce hydropower generation and thereby hamper the renewable energy transition. This is relevant for policymakers and water managers by allowing them to anticipate the impact of climate change on hydropower generation and better plan a renewable energy transition. The study was supported by the project CLIMALERT: Climate AlertSmart System for Sustainable Water and Agriculture, an ERA-NET initiated by JPI Climate (ERA4CS programme) co-funded by the EU commission (Grant Agreement 690462) and FCT (ERA4CS/0004/2016). Jose Pedro Ramiao was supported by Fundacao para a Ciencia e Tecnologia (FCT) (SFRH/BD/141486/2018) and the European Social Fund through the "Programa Operacional Regional do Norte" of the European Commission. Claudia Carvalho-Santos is supported by the "Contrato-Programa" UIDP/04050/2020 funded by national funds through the Fundacao para a Ciencia e Tecnologia I.P. Rute Pinto gratefully acknowledges the support of Global Water Futures as part of the Canada First Research Excellence Fund. Published online: 6 December 2022