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Projeto de investigação
RINGS – Responsible, sustainable and circular energy system within planetary boundaries
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Optimal design and techno-economic analysis of hybrid renewable energy systems
Publication . Ayed, Yasmine; Al Afif, Rafat; Fortes, Patricia; Pfeifer, Christoph; Faculdade de Ciências e Tecnologia (FCT); CENSE - Centro de Investigação em Ambiente e Sustentabilidade; Taylor & Francis
This study explores the techno-economic feasibility of, both off-grid and on-grid, hybrid renewable energy systems for remote rural electrification in Thala City, located in the highest region of Tunisia, using wind and biomass resources. Employing Hybrid Optimization of Multiple Energy Resources based on different scenarios includes grid-connected and stand-alone configurations with pumped storage hydropower and lead acid battery storage while minimizing the levelized cost of energy, the net present cost, and greenhouse gas emissions. The optimal configuration wind/biomass/pumped-hydro storage/Converter grid-connected, minimizes the levelized cost of energy (LCOE) and net present cost (NPC), resulting in a cost of 501,540 US$ and LCOE of 0.042 US$/kWh. Notably, 7% of electricity is generated from olive mill waste, 69% from wind turbines, and 24% is purchased from the grid. This hybrid system emits 342 tons/year of CO2, 76% less than a grid-alone system, contributing to an annual CO2 reduction of 1000 tons.
Competing water uses between agriculture and energy
Publication . Fortes, Patrícia; Simões, Sofia G.; Armada Brás, Teresa; Amorim, Filipa; CENSE - Centro de Investigação em Ambiente e Sustentabilidade; Elsevier
Climate change may increase water needs for irrigation in southern Europe competing with other water uses, such as hydropower, which may likely be impacted by lower precipitation. Climate change will also potentially affect the variability and availability of other renewable energy resources (solar and wind) and electricity consumption patterns. This work quantifies the effect of competition for water use between irrigation and hydropower in the future 2050 Portuguese carbon-neutral power sector and under Representative Concentration Pathway 8.5 climate change projections. It uses the power system eTIMES_PT model to assess the combined effects of climate change on the cost-optimal configuration of the power sectorconsidering changes in irrigation, hydropower, wind and solar PV availability. eTIMES_PT is a linear optimisation model that satisfies electricity demand at minimal total power system cost. Results show that, by 2050, climate change can lead to an increase in annual irrigation water needs up to 12% in Tagus and 19% in Douro watersheds (from 2005 values), with substantially higher values for spring (up to 84%). Combining these increased water needs with the expected reduction in river runoff can lead to a decline in summer and spring hydropower capacity factors from half to three times below current values. By 2050, concurrent water uses under climate change can reduce hydropower generation by 26–56% less than historically observed, mainly in summer and spring. Higher solar PV, complemented with batteries’ electricity storage, can offset the lower hydropower availability, but this will lead to higher electricity prices. Adequate transboundary water management agreements and reducing water losses in irrigation systems will play a key role in mitigating climate impacts in both agriculture and power sector.
Targeting energy savings? Better on primary than final energy and less on intensity metrics
Publication . Rodríguez, M.; Teotónio, C.; Roebeling, P.; Fortes, P.; CENSE - Centro de Investigação em Ambiente e Sustentabilidade; Elsevier Science B.V., Amsterdam.
Energy efficiency is a critical issue in public policies, as it is the key to decoupling economic growth and energy use. These objectives are becoming even more relevant to addressing the energy crisis and the new geopolitical scenarios delivered by the Ukraine war. Although several papers have analyzed energy efficiency goals, this paper focuses on energy savings targets, which represent the main efficiency metric for the European Union. This paper fills a gap in literature by analyzing the economic and environmental impacts of attaining energy efficiency targets through an energy fiscal policy, simulated by a hybrid computable general equilibrium model with technological detail. Six scenarios are defined for energy savings in primary/final energy consumption of fossil-fueled/all energy products, using Portugal as a case study. Relevant insights for policy makers from the simulated scenarios include: (i) achieving energy saving targets by alternative means, i.e., directed at primary or final energy consumption, provide heterogeneous impacts on the efficiency of the energy system and GDP, and some unexpected and undesirable outcomes concerning environmental impacts; (ii) a relatively lower taxation of all energy products deliver larger and more distorting impacts on electricity generation than higher taxes on fossil fuels only (a counterintuitive result), (iii) policies aiming to reduce primary energy instead of final energy provide the best outcomes (further increases in the efficiency of the energy system with smoother economic impacts), thereby pointing against the European Energy Taxation directive principle that taxation should be levied on final products, regardless of inputs used in their production and (iv) and targets should not be set up based on energy intensity indicators. Hence, it is shown that the size of the trade-off between economic and environmental concerns depends on where (primary or final energy consumption) and what (fossil or all energy products) energy savings are targeted.
How can green hydrogen from North Africa support EU decarbonization? Scenario analyses on competitive pathways for trade
Publication . Pinto, Maria Cristina; Simões, Sofia G.; Fortes, Patricía; CENSE - Centro de Investigação em Ambiente e Sustentabilidade; Faculdade de Ciências e Tecnologia (FCT); Elsevier Science B.V., Amsterdam.
The carbon-neutrality target set by the European Union for 2050 drives the increasing relevance of green hydrogen as key player in the energy transition. This work uses the JRC-EU-TIMES energy system model to assess opportunities and challenges for green hydrogen trade from North Africa to Europe, analysing to what extent it can support its decarbonization. An important novelty is addressing uncertainty regarding hydrogen economy development. Alternative scenarios are built considering volumes available for import, production costs and transport options, affecting hydrogen cost-effectiveness. Both pipelines and ships are modelled assuming favourable market conditions and pessimistic ones. From 2040 on, all available North African hydrogen is imported regardless of its costs. In Europe this imported hydrogen is mainly converted into synfuels and heat. The study aims to support policymakers to implement effective strategies, focusing on the crucial role of green hydrogen in the decarbonization process, if new competitive cooperations are developed.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
CEEC IND 3ed
Número da atribuição
2020.00038.CEECIND/CP1586/CT0017