• Energy Research

For being densely populated and urbanized, and for concentrating high-value economic activities, estuarine regions have an increased energy demand, which boosts the claim for new, efficient, renewable, and safe energy production. Among these technologies, hydrokinetic energy conversion systems are potentially well-suited for estuaries. However, in the actual context of climate change, it is important to know how changes in mean sea level may affect hydrokinetic energy production. This work proposes a methodology to assess the hydrokinetic energy potential for future scenarios using numerical hydrodynamic modeling techniques. Applied to the Douro estuary, several scenarios considering present conditions, as well as medium (2050) and long-term (2100) predictions under different Shared Socioeconomic Pathways are proposed. The results revealed that the studied region maintains a high dependence on freshwater discharge until 2100, although tidal oscillation is also significantly perceived in the entire estuary. Overall, hydrokinetic power potential will not increase with the mean sea level rise and will instead be considerably lower. Therefore, a decline in the kinetic energy available for exploitation is expected with increasing CO2 emissions, along with the associated intensification of sea level rise. Results reinforce the need to perform local studies to evaluate future trends in hydrokinetic energy production. This research was supported by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 through national funds provided by FCT – Foundation for Science and Technology and European Regional Development Fund (ERDF), and by the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017), co-financed by NORTE 2020, Portugal 2020, and the European Union through the ERDF, and by FCT through national funds. The authors would like to thank the Instituto Hidrográfico, EDP Energias de Portugal and the projects ECOIS (POCTI/CTA/48461/2002), RAIA (0313-RAIA-1-E), RAIA. co (0520-RAIA CO-1-E), RAIA tec (0688-RAIA TEC-1-P), ECORISK (NORTE 07 0124-FEDER-000054) and INNOVMAR/ECOSERVICES (NORTE 01 0145-FEDER-000035) for the data provided.

Riparian areas in the Cantabrian Atlantic ecoregion (northwest Portugal) play a key role in soil formation and conservation, regulation of nutrient and water cycle, creation of landscape aesthetic value and the preservation of biodiversity. The maintenance of their ecological integrity is crucial given the ever increase in multiple anthropogenic (water demand and agriculture) and climatic pressures (droughts and extreme events). We developed a transferable remote sensing approach, taking advantage of the latest freely available technologies (Sentinel-2 and Copernicus Land products), to detect intra-annual and inter-annual changes in riparian vegetation productivity at the river basin scale related to water stress. This study has used the normalized difference vegetation index (NDVI) to investigate riparian vegetation productivity dynamics on three different vegetation types (coniferous, broadleaved and grassland) over the past 5 years (2015-2019). Our results indicated that inter-annual seasonality differed between drier (2017) and wetter (2016) years. We found that intra-annual dynamics of NDVI were influenced by the longitudinal river zonation. Our model ranked first (r2m = 0.73) showed that the productivity of riparian vegetation during the dry season was positively influenced by annual rainfall and by the type of riparian vegetation. The emergent long lags between climatic variation and riparian plant productivity provides opportunities to forecast early warnings of climatically-driven impacts. In addition, the different average productivity levels among vegetation types should be considered when assessing climatic impacts on riparian vegetation. Future applications of Sentinel 2 products could seek to distinguish riparian areas that are likely to be more vulnerable to changes in the annual water balance from those that are more resistant under longer-term changes in climate.

Two out of three Europeans live in towns and cities, and this number is (still) increasing. By attracting more inhabitants, urban areas are facing new challenges, particularly in terms of social and environmental issues. Meeting the challenges of increasing urban pressure may rest on citizens’ active involvement and cross-commitment promoted by local authorities, simultaneously exploring and respecting the social, cultural and heritage structures – the city’s identity. Some cities face more demanding challenges than others. There are other factors associated with the identity process, where the culture and history tend to be relevant indicators, especially in historic cities. Reinforcing the bonds of local identity may facilitate the citizens’ engagement in the common effort to build an environmental and sustainable city. The city of Guimaraes faces such challenges. In this context, the European Green Capital Award, which yearly distinguishes a European city based on its environmental, economics and life quality efforts, encouraging best practices sharing, corresponds to certifying a certain city management paradigm.