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- Biogas reforming as a sustainable solution for hydrogen production: Comparative environmental metrics with steam-methane reforming and water electrolysis in the Portuguese contextPublication . Bento, Cláudia; Lopes, Tiago; Rodrigues, Pedro; Gírio, Francisco; Silva, CarlaABSTRACT: This study delves into the dynamics of hydrogen production, with a specific focus on biogas reforming (BGSMR) for hydrogen generation. It compares the environmental impact of this solution with hydrogen production from natural gas-steam reforming (NGSMR) and commercial electrolysis in the Portuguese context. Various metrics, including carbon footprint, water depletion, energy utilization, and waste valorization are employed for a comprehensive comparison. The assessment explores the impact of operational parameters and different off-gas combustion scenarios, incorporating water recycling practices. Due to challenges in obtaining detailed data on the actual reforming process, the study relies on process simulation techniques, primarily using DWSIM. Commercially available data for water electrolysers were used for comparison. In the context of decarbonizing power systems, hydrogen from water electrolysis emerges as a competitive option only in a scenario where the power system is 100% reliant on renewable sources, particularly with respect to the carbon footprint metric. Biogas systems, characterized by near-zero carbon emissions, stand out as a favourable option from the near future to the long run. This research contributes valuable insights into the dynamics of hydrogen production, shedding light on environmentally viable alternatives across a range of power system scenarios.
- Atlas Nacional do H2 Verde SustentávelPublication . Ponce Leao, Maria Teresa; Simoes, Sofia; Simões, Teresa; Quental, Lídia; Catarino, Justina; Amorim, Filipa; Brás, Teresa; Patinha, Pedro; Lopes, Tiago; Rodrigues, Carlos; Machado, Susana; Rangel, C. M.; Gírio, Francisco; Picado, AnaRESUMO: O "Atlas Nacional do H2 Verde Sustentável" tem como objetivo apoiar o processo de decisão quanto à localização de projetos de produção de hidrogénio verde no território de Portugal continental. O Atlas foi desenvolvido pelo LNEG em colaboração com várias entidades públicas e privadas nacionais. De uma forma mais geral, apoia à a transição para um país neutro em carbono, desenvolvendo uma economia de baixo carbono, liderando em inovação e desenvolvimento tecnológico.
- Correction: Correia et al. Sustainability Assessment of 2G Bioethanol Production from Residual Lignocellulosic Biomass. Processes 2024, 12, 987Publication . Correia, Bárbara; Matos, Henrique A.; Lopes, Tiago; Marques, Susana; Gírio, FranciscoError in Table: In the original publication [1], there was a mistake in Table 8 as published. The presented cost of purchased equipment and Total CAPEX cost shall not differ between the two scenarios. The purchased equipment cost and Total CAPEX cost should be, for both scenarios, 21.35 and 75.66M€, respectively. The corrected Table 8 appears below. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.
- Efficient conversion of agricultural and forest residues into bioethanol: BIOFLEXPOR as flexible technology towards sugar-based biorefineries [Poster]Publication . Marques, Susana; Paixão, Susana M.; Alves, Luís; Gomes, Miguel; Eusebio, Ana; Lopes, Tiago; Coelho, Lucas; Diebold, Eduardo; Gírio, FranciscoABSTRACT: Lignocellulosic ethanol is in the upfront of advanced biofuels to be commercialized worldwide. However, the commercial deployment of 2G ethanol is dependent of high biomass availability and cost-effective supply. In Europe, some agricultural residues are presently underused and constitute attractive renewable resources. In addition, residual forest biomass, non-seasonably available at low cost, might be complementarily used as raw material boosting the economy of biorefineries. In this context, the present work deals with the development of an innovative and sustainable technological strategy to produce advanced bioethanol using agricultural and forestry residual biomass. The bioprocess involves enzymatic hydrolysis of major lignocellulose polysaccharides (cellulose and xylan) with commercial enzymes and fermentation of the resulting sugars. A pre-treatment step should firstly be accomplished to make cellulose more amenable to hydrolytic enzymes, and the prototype is based on a proprietary non-catalysed steam explosion technology, i.e., without the addition of acids and using only high-pressure steam, called FLEXBIO™, which was initially developed in Brazil by the company STEX and since 2019 in partnership with LNEG. The proposed technology has been successfully demonstrated in a relevant environment (TRL 5) for the efficient conversion of corn stover, olive tree pruning and eucalyptus-based forest residual biomass, yielding close to 150 L of ethanol per metric tonne (dry basis) of biomass, corresponding to an overall yield close to 75% of maximal theoretical yield for glucan conversion. Both enzymatic hydrolysis and fermentation steps have achieved yields superior to 85% of the maximal theoretical conversion, and the optimization of process configuration, targeting the best integration with pre-treatment, is now under progress and higher yields will be expected. Given the higher xylan content of corn stover, both cellulose and xylan fractions are pursued. In addition, the upgrading potential of all wastewater streams will also be assessed, by studying the feasibility of its combined use to increase the ethanol yield as alternative to its use for biogas production through anaerobic digestion, with the goal to reach near-zero waste. In conclusion, the present study reveals the industrial potential of this flexible technology that might be applied to implement distinct small-scale sugar-based biorefineries by converting several lignocellulosic raw materials into distinct marketable biofuels/biomaterials, promoting the circular bioeconomy.
- Economia do Hidrogénio Verde: Ferramentas para o Apoio à Decisão [Poster]Publication . Simoes, Sofia; Simões, Teresa; Quental, Lídia; Catarino, Justina; Amorim, Filipa; Brás, Teresa; Patinha, Pedro; Lopes, Tiago; Rodrigues, Carlos; Machado, Susana; Rangel, C. M.; Gírio, Francisco; Picado, Ana; Ponce Leao, Maria Teresa; Portillo, Juan C. C.RESUMO: O Hidrogénio (H2) Verde perspetiva-se como um vetor energético indispensável para alcançar a neutralidade carbónica em 2050, porém a economia deste vetor está em desenvolvimento e os agentes económicos precisam de fontes de informação confiáveis e ajustadas ao contexto nacional e Europeu. Neste sentido, o LNEG desenvolve investigação em vários domínios relacionados com o H2 verde, desde o estudo e desenvolvimento de processos de produção eficientes até a análise e modelos de negócios para estudar a viabilidade económica das cadeias de valor, passando pela análise de políticas públicas e ao mesmo tempo fornecendo informação de alto valor acrescentado para o apoio à decisão de entidades públicas e privadas. Com o objetivo de estabelecer pontes entre a investigação e a economia do H2 verde foram criadas ferramentas associadas à avaliação de projetos presentes e futuros em todas as cadeias de valor relacionadas. Uma destas ferramentas é o Atlas Nacional do H2 Verde Sustentável (LNEG, 2022) disponível para o público desde 2022 e que está a ser atualizado para incorporar os custos de produção, transporte e distribuição do hidrogénio verde em Portugal. O LNEG participa em importantes agendas mobilizadoras, como a Moving2Neutrality (LNEG, 2023) ou a H2Driven (LNEG, 2024), as quais abordam o desafio da transição energética no setor dos transportes, produzindo combustíveis sustentáveis, com um foco no hidrogénio e e-combustíveis verdes. O LNEG está a desenvolver um simulador de custos nivelados do hidrogénio incluindo todas as fases da cadeia de valor (produção, armazenagem, distribuição e transformação) produto da investigação do LNEG com os parceiros da agenda e que será disponibilizado em 2024 para o público geral. Este Poster apresenta o trabalho desenvolvido e em curso para estas ferramentas.
- Sustainability Assessment of 2G Bioethanol Production from Residual Lignocellulosic BiomassPublication . Correia, Bárbara; Matos, Henrique A.; Lopes, Tiago; Marques, Susana; Gírio, FranciscoABSTRACT: The development of sustainable biofuels can help to reduce the reliance on fossil fuels and mitigate the impact of climate change. This study analyzes bioethanol production from agro-forestry residual biomass, namely eucalyptus residues and corn stover. The study includes process simulation using Aspen Plus software, followed by economic analysis and life cycle assessment (LCA) with the help of SimaPro software and by applying the environmental footprint (EF) 3.0 method. The economic analysis on the biorefinery’s economic viability, equipment, and production costs reveals a positive decision for bioethanol production from eucalyptus residues due to logistical and transportation costs. The minimum ethanol selling price (MESP) obtained was 2.19 €/L and 2.45 €/L for eucalyptus residues and corn stover, respectively. From the LCA with a functional unit of 1 MJ of ethanol, bioethanol production from eucalyptus residues results in a single score impact of 37.86 µPt, whereas for corn stover, it is 33.47 µPt. In the climate change impact category, the eucalyptus residues scenario has an impact of 0.264 kg CO2 eq/MJ ethanol while corn stover leads to 0.254 kg CO2 eq/MJ ethanol. In-situ enzyme production, heat integration, and the use of renewable energy sources were also analyzed. Combining in situ enzyme production with renewable energy sources lowers CO2 equivalent emissions by 89% for both feedstocks, in comparison to the base-case scenario.
- Carbon footprint assessment of microalgal biomass production, hydrothermal liquefaction and refining to sustainable aviation fuel (SAF) in mainland PortugalPublication . Pires, Renata; Silva, Tiago; Ribeiro, Cláudia; Costa, Luis; Matos, Cristina T.; Costa, Paula; Lopes, Tiago; Gírio, Francisco; Silva, CarlaABSTRACT: Industrial liquid effluents (e.g., from fertilizer industry) and flue gas streams (e.g., CO2-rich, from cement industry) arise as an opportunity for waste valorization. Microalgae are suitable biomass for assimilating both effluents at the cultivation stage. Under a biorefinery concept, given the urge for energy transition in the aviation sector, this research explores the transformation of a microalgae consortium grown at an industrial site in Portugal and its subsequent harvesting, hydrothermal liquefaction (HTL), and bio-oil refining. A life cycle assessment (LCA) approach is undertaken with two functional units (FU): 1 kg of microalgae dry-cell weight (dw) and 1 MJ of bio-jet fuel. The latter follows an attributional approach with energy allocation for comparison with the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) guidelines. HTL is based on data from bench-scale experiments and literature, whereby the Petroleum Refinery Life Cycle Inventory Model (PRELIM) is used to mimic bio-oil refining. Following this approach, achieving Sustainable Aviation Fuel (SAF) compliance requires net-zero electricity (0 gCO2eq/kWh), with an HTL bio-oil yield of 55.6 % dw (the maximum observed), a minimum refining bio-jet fuel yield of at least 16 %. Alternatively, an HTL bio-oil yield of 36.9 % dw (the median observed) with a refining efficiency of at least 24.3 %.
- Process simulation and techno-economic assessment for direct production of advanced bioethanol using a genetically modified Synechocystis sp.Publication . Lopes, Tiago; Cabanas, Catarina; Silva, André; Fonseca, Diana; Santos, Edgar; Guerra, L. Tiago; Sheahan, Con; Reis, Alberto; Gírio, FranciscoABSTRACT: A techno-economic assessment for the direct production of ethanol using a genetically-modified microalgae has been studied. It was considered two main scenarios for process modelling: i) bioenergy-driven microalgae plant, i.e., focused on the production of fuel-grade ethanol and biogas for CHP and, ii) biorefinery-driven microalgae plant, focused on the recovery of added-value bioproducts (zeaxanthin and phycocyanin) along with ethanol and CHP production. These main scenarios and several variants were modelled and optimized for a small-scale demo plant of 1000 Lethanol/day and extrapolated for larger production capacities. Results showed that despite the innovative approach of direct production of ethanol by microalgae, the bioenergy-driven scenario is non-feasible under the studied conditions. Conversely, ethanol production becomes economically feasible as co-product in the biorefinery-driven scenario although having payback periods>10 years. Furthermore, if only bio-based products are produced the NPV and the payback are even more positive, 104.8 M€ and ca. 5 years, respectively.
- Systematic and Bibliometric Review of Biomethane Production from Biomass-Based Residues: Technologies, Economics and Environmental ImpactPublication . Tiago, Gonçalo A. O.; Rodrigo, Naresh P. B.; Lourinho, Gonçalo; Lopes, Tiago; Gírio, FranciscoABSTRACT: Fossil fuels drive global warming, necessitating renewable alternatives such as biomethane (or renewable natural gas). Biomethane, primarily produced through anaerobic digestion (AD), offers a cleaner energy solution but is limited by the slow AD process. Biomass gasification followed by syngas methanation has emerged as a faster alternative. This review examines advancements in these processes over the last decade (2015–2024), focusing on techno-economic and life cycle assessment (LCA) studies. Techno-economic analyses reveal that biomethane production costs are influenced by several factors, including process complexity, feedstock type and the scale of production. Smaller gasification units tend to exhibit higher capital costs (CAPEX) per MW capacity, while feedstock choice and process efficiency play significant roles in determining overall production costs. LCA studies highlight higher impacts for gasification and methanation due to energy demands and associated emissions. However, integrating renewable hydrogen production through electrolysis, along with innovations such as sorption-enhanced gasification (SEG), can enhance overall system efficiency and reduce environmental impacts. This review critically evaluates the technical and economic challenges, along with the opportunities for optimizing biomethane production, and discusses the potential for these technologies to contribute to sustainable bioenergy solutions in the transition to a low-carbon economy.
- Production of Hemicellulosic Sugars from Residual Lignocellulosic Biomass in an Integrated Small-Scale Biorefinery: Techno-Economic and Life Cycle AssessmentsPublication . Lopes, Tiago; Duarte, Luís C.; Carvalheiro, Florbela; Cardona, Carlos A.; Gírio, FranciscoABSTRACT: Biorefineries design, as for other industries, usually target the economy of scale approach, maximizing processing capacities to achieve economic viability. However, the installation of large-scale biorefineries has some drawbacks, namely their high capital costs and the difficulty to assure a proper supply of biomass at regional level. Small-scale, self-sustainable, biorefineries can solve several of the challenges of their larger competitors and are also reported to expand environmental and social benefits, but several hurdles for their deployment still exist. This chapter describes a methodology for the implementation of an integrated small-scale self-sustainable biorefinery in a rural area, based on a design that takes advantage of the synergies of processing two types of feedstock (corn stover and swine manure). A detailed explanation for the process selection by performing a heuristic analysis, process simulation, mass and energy balances alongside with the techno-economic assessment of the biorefinery is provided. The full life cycle assessment (LCA) of producing xylo-oligosaccharides (XOS) and ethanol from lignocellulosic residues, i.e. corn stover, under a biorefinery concept to be located in Portugal is also assessed.
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