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AbstractThis study compared the economic and environmental impacts of torrefaction on bioenergy supply chains against conventional pellets for scenarios where biomass is produced in Mozambique, and undergoes pre‐processing before shipment to Rotterdam for conversion to power and Fischer‐Tropsch (FT) fuels. We also compared the impacts of using different land quality (productive and marginal) for feedstock production, feedstocks (eucalyptus and switchgrass), final conversion technologies (XtY and CXtY) and markets (the Netherlands and Mozambique). At current conditions, the torrefied pellets (TOPs) are delivered in Rotterdam at higher cost (7.3–7.5 $/GJ) than pellets (5.1–5.3 $/GJ). In the long term, TOPs costs could decline (4.7–5.8 $/GJ) and converge with pellets. TOPs supply chains also incur 20% lower greenhouse gas (GHG) emissions than pellets. Due to improved logistics and lower conversion investment, fuel production costs from TOPs are lower (12.8–16.9 $/GJFT) than from pellets (12.9–18.7 $/GJFT). Co‐firing scenarios (CXtY) result in lower cost fuel (but a higher environmental penalty) than 100% biomass fired scenarios (XtY). In most cases, switchgrass and the productive region of Nampula provide the lowest fuel production cost compared to eucalyptus and the marginally productive Gaza region. Both FT and ion in Mozambique are more costly than in Rotterdam. For the Netherlands, both FT and power production are competitive against average energy costs in Western Europe. The analysis shows that large‐scale bioenergy production can become competitive against fossil fuels. While the benefits of TOPs are apparent in logistics and conversion, the current higher torrefaction costs contribute to higher biofuel costs. Improvements in torrefaction technology can result in significant performance improvements over the future chain. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

This paper analyzes the ability of water utilities to contribute to sustainability transition processes. More specifically, we compare the capacity of utilities, embedded in purely public, mixed and largely private governance modes, to innovate. We employ dynamic capabilities as core indicators for innovativeness and therefore as major enabling factors for sustainable sector transitions. We assess the relationship between governance modes and innovation by conducting an in-depth comparative analysis of three water utilities, each within a differing governance mode along the public-to-private continuum: Zurich, Berlin and Leeds. While we find that the private and mixed governance modes have an increased degree of innovativeness, they perform lower in terms of static sustainability criteria than the public mode. We therefore conclude that the impact of privatization on sustainability transitions in the water sector involves multi-dimensional trade-offs between static and dynamic sustainability criteria.

The chemical and petrochemical sector is by far the largest industrial energy user, accounting for 30% of the industry's total final energy use. However, due to its complexity its energy efficiency potential is not well understood. This article analyses the energy efficiency potential on a country level if Best Practice Technologies (BPT) were implemented in chemical processes. Two approaches are applied and an improved dataset referring to Europe has been developed for BPT energy use. This methodology has been applied to 66 products in fifteen countries that represent 70% of chemical and petrochemical sector's energy use worldwide. The results suggest a global energy efficiency potential of 16% for this sector, excluding savings in electricity use and by higher levels of process integration, combined heat and power (CHP) and post-consumer plastic waste treatment. The results are more accurate than previous estimates. The results suggest significant differences between countries, but a cross-check based on two different methods shows that important methodological and data issues remain to be resolved. Further refinement is needed for target setting, monitoring and informing energy and climate negotiation processes. For the short and medium term, a combination of benchmarking and country level analysis is recommended.

Abstract The present analysis was conducted as the first study to investigate the biochemical methane potential of four different agro-industrial wastewaters originating from chocolate, slaughterhouse, gum, and beet sugar industries under the same anaerobic fermentation conditions. To the best of our knowledge, no previous study has specifically attempted to pinpoint a hybrid programming strategy for making a quantitative description of the anaerobic biodegradability of these waste streams. Thus, considering the scarcity of the literature in this field, a comprehensive study was conducted to evaluate the amount of bio-methane obtainable from the investigated organic wastes and to predict their kinetics using three different sigmoidal microbial growth curve models (modified Gompertz equation, transference function (reaction curve-type model), and logistic function) within the framework an original MATLAB®-based coding scheme. The results showed that methane productions started immediately after 4 h of incubation for all substrates and reached their maximum rates of 118, 116, 108, 34 mL CH4/g VS/day, respectively, for wastewaters from chocolate, slaughterhouse, gum, and beet sugar industries. The corrected mean steady state methane contents were 61.7%, 73.4%, 62.8%, and 62.1% in the respective order. The highest methane yield (943 mL CH4/g VS) was obtained from the slaughterhouse wastewater, and this value was 1.32, 1.58, and 4.56 times higher than those obtained in the anaerobic digestion of chocolate, gum, and beet sugar wastewaters, respectively. Among the three kinetic models tested, the logistic function best explained the behavior of the observed data of all substrates using a Quasi-Newton cubic line search procedure (R2 = 0.987–0.996) with minimum number of non-linear iterations and function counts. Deviations between the measured and the outputs of the best-fit kinetic model were less than 4.3% in prediction of methane production potentials, suggesting that the proposed computational methodology could be used as a well-suited and robust approach for modeling and optimization of a highly non-linear biosystem.

In this paper we evaluate two approaches for estimating CO2 emission reduction from electricity savings: one based on average CO2 intensities of electricity generation and another that relies on marginal CO2 intensities. It is found that the average CO2 intensity approach has a significant shortcoming when it comes to scenario-based approaches for CO2 emission reduction. This shortcoming lies in the chicken-egg problem created, where larger future electricity savings are actually big enough to change the CO2 intensity in such a way that it cannot be used anymore to estimate the CO2 emission reduction. We show that in these cases the marginal approach is preferred. To correctly apply this approach, it is important to determine the CO2 intensity of the future power mix which will not be built in order to avoid under or overestimation of the CO2 savings calculated. We propose a seven-step approach which can be used in scenario-based potential studies as guidance for estimating the CO2 emission reductions from not only electricity savings but also renewable electricity and mitigation options that consume electricity such as electric cars and heat pumps. Using our approach would avoid a disconnection of the CO2 reduction potential with the underlying reference scenario. © 2013 Elsevier Ltd.

Fossil fuel substitution with biomass is one of the measures to reduce carbon dioxide (CO2) emissions. This paper estimates the cost-effectiveness of raising industrial steam and producing materials (i.e. chemicals, polymers) from biomass. We quantify their long-term global potentials in terms of energy saving, CO2 emission reduction, cost and resource availability. Technically, biomass can replace all fossil fuels used for the production of materials and for generating low and medium temperature steam. Cost-effective opportunities exist for steam production from biomass residues and by substitution of high value petrochemicals which would together require more than 20 exajoules (EJ) of biomass worldwide in addition to baseline by 2030. Potentials could double in 2050 and reach 38-45 EJ (25% of the total industrial energy use), with most demand in Asia, other developing countries and economies in transition. The economic potential of using biomass as chemical feedstock is nearly as high as for steam production, indicating its importance. The exploitation of these potentials depends on energy prices and industry's access to biomass supply. Given the increasing competition for biomass from several economic sectors, more resource efficient materials need to be developed while steam production is already attractive due to its high effectiveness for reducing CO2 emissions per unit of biomass.

A indústria petrolífera, que tem como um dos produtos o plástico, e a do ferro e aço são das maiores emissoras mundiais de Gases com Efeito de Estufa (GEE). Assim, atualmente, com as crescentes preocupações ambientas da população, torna-se urgente estudar o impacte ambiental das fábricas produtoras de embalagens de plástico e metal. Desse modo, a presente dissertação foi realizada na Colep Packaging Portugal e teve como objetivo calcular a pegada de carbono da fábrica referente ao ano de 2022. A avaliação da pegada de carbono foi realizada tendo como linhas orientadoras a metodologia Greenhouse Gas Protocol e sempre que possível, foram utilizados os fatores de emissão de origem primária. A pegada de carbono é dividida em três âmbitos: o primeiro é referente às emissões diretas da empresa relatora; o segundo são emissões indiretas para a produção de energia; o terceiro refere-se a emissões que ocorrem como consequência da atividade da empresa relatora. É possível afirmar que este mesmo objetivo foi atingido, obtendo-se como resultado 7 408,235 t CO2 eq de âmbito 1 (7,03%), 2 846,705 t CO2 eq de âmbito 2 (2,70%) e 95 075,239 t CO2 eq de âmbito 3 (90,27%). Globalmente, o valor calculado foi 105 330,179 t CO2 eq. As categorias que mais contribuíram para este valor da pegada de carbono são os bens e serviços adquiridos, o fim de vida dos produtos vendidos e o consumo de gás natural. Estas três categorias emitiram, em 2022, 87 732,707 t CO2 eq, o que corresponde a 83,29% das emissões totais da Colep Packaging Portugal. Para calcular a pegada de carbono foi necessário realizar um inventário, em primeiro lugar, aos tipos de energia consumida. Nestes parâmetros estão incluídos o gás natural, propano, gasóleo, gasolina e líquidos refrigerantes para o âmbito 1 e a eletricidade para o âmbito 2. Foi também realizado um inventário para o âmbito 3 a todas as matérias-primas, serviços e bens capitais adquiridos, ao transporte a montante (de matérias-primas) e a jusante (de produtos vendidos), aos resíduos gerados no processo produtivo, às viagens de negócios e diárias dos colaboradores, aos bens alugados a montante (veículos de leasing e paletes) e a jusante (edifícios), ao processamento dos produtos vendidos e ao fim de vida destes. Também se analisou o uso dos produtos vendidos, os franchises da empresa e os investimentos, porém, estas categorias não registaram valores. De maneira a reduzir o valor da pegada de carbono sugere-se a realização de algumas medidas. Ao todo são 16 de onde se destacam a substituição dos veículos a combustão por elétricos, a utilização de camiões elétricos, a utilização de energia 100% renovável, a utilização de comboios para transporte superior a 250 km, a instalação de painéis solares, o aumento da eficiência energética e a incorporação de reciclado nas embalagens metálicas. Ao serem implementadas, as 16 medidas permitem reduzir em 54 262,702 t CO2 eq, o que corresponde a 51,52% do atual valor global.

O estágio curricular desenvolvido como requisito parcial para a obtenção de grau de mestre foi realizado na SIMDOURO – Estação de Tratamento de Águas Residuais (ETAR) de Paço de Sousa. O tema desenvolvido foi o estudo da otimização da digestão anaeróbia na referida ETAR. Os ensaios tiveram como objetivo estudar a influência de diversos fatores na produção de biogás: diferentes pré-tratamentos enzimáticos (simples e combinados) e térmicos nas lamas mistas; temperatura do processo; codigestão de lamas mistas com microalgas e com efluente rico em óleos e gorduras provenientes de uma indústria de produção de biodiesel. Foram realizados testes em sistema fechado para avaliação do potencial de produção de metano, BMP (biochemical methane potential) com uma duração aproximada de 14 dias. O pré-tratamento enzimático com apenas uma enzima causou uma redução na produção de biogás, sugerindo uma possível inibição do processo de digestão anaeróbia. A produção de biogás na amostra pré-tratada enzimática e termicamente foi maior do que na amostra submetida apenas ao pré-tratamento enzimático. Quanto ao grupo de ensaios com enzimas combinadas, o uso simultâneo de 3 grupos de enzimas (proteases, lípases e celulases) deu origem a maior produção de biogás, correspondente a 0,128 Nml/mg sólidos voláteis iniciais (SVi). O uso de enzimas celulolíticas originou menor produção específica, sendo esta de 0,121 Nml/mg SVi. Verificou-se que a codigestão de lamas mistas com até 4,5 % de microalga Chlorella vulgaris não teve efeito inibidor. Para as temperaturas testadas (43 e 48 ºC), a maior produção de biogás deu-se a 43 ºC. A codigestão com 0,94%v/v de um efluente rico em óleos e gorduras resultou na produção de um volume adicional de biogás de 18,4%. O estudo desenvolvido levou ainda a perceber que 24% do biogás produzido pela ETAR é desperdiçado devido à baixa potência elétrica do cogerador (170 kW). Verificou-se que o uso de um cogerador com uma maior potência (226 kW) eliminaria essas perdas, produzindo energia elétrica equivalente a 1 976 764 kWh anual e gerando assim uma receita bruta correspondente a 151% das vendas atuais, que após a liquidação da fatura de energia injetada na rede resultaria num saldo extra de +28 325 € anuais