Evaluation of thermochemical biomass conversion in fluidized bed

Dado o aumento acelerado dos preços dos combustíveis fósseis e as incertezas quanto à sua disponibilidade futura, tem surgido um novo interesse nas tecnologias da biomassa aplicadas à produção de calor, eletricidade ou combustíveis sintéticos. Não obstante, para a conversão termoquímica de uma partícula de biomassa sólida concorrem fenómenos bastante complexos que levam, em primeiro lugar, à secagem do combustível, depois à pirólise e finalmente à combustão ou gasificação propriamente ditas. Uma descrição relativamente incompleta de alguns desses estágios de conversão constitui ainda um obstáculo ao desenvolvimento das tecnologias que importa ultrapassar. Em particular, a presença de elevados conteúdos de matéria volátil na biomassa põe em evidência o interesse prático do estudo da pirólise. A importância da pirólise durante a combustão de biomassa foi evidenciada neste trabalho através de ensaios realizados num reator piloto de leito fluidizado borbulhante. Verificou-se que o processo ocorre em grande parte à superfície do leito com chamas de difusão devido à libertação de voláteis, o que dificulta o controlo da temperatura do reator acima do leito. No caso da gasificação de biomassa a pirólise pode inclusivamente determinar a eficiência química do processo. Isso foi mostrado neste trabalho durante ensaios de gasificação num reator de leito fluidizado de 2MWth, onde um novo método de medição permitiu fechar o balanço de massa ao gasificador e monitorizar o grau de conversão da biomassa. A partir destes resultados tornou-se clara a necessidade de descrever adequadamente a pirólise de biomassa com vista ao projeto e controlo dos processos. Em aplicações de engenharia há particular interesse na estequiometria e propriedades dos principais produtos pirolíticos. Neste trabalho procurou-se responder a esta necessidade, inicialmente através da estruturação de dados bibliográficos sobre rendimentos de carbonizado, líquidos pirolíticos e gases, assim como composições elementares e poderes caloríficos. O resultado traduziu-se num conjunto de parâmetros empíricos de interesse prático que permitiram elucidar o comportamento geral da pirólise de biomassa numa gama ampla de condições operatórias. Para além disso, propôs-se um modelo empírico para a composição dos voláteis que pode ser integrado em modelos compreensivos de reatores desde que os parâmetros usados sejam adequados ao combustível ensaiado. Esta abordagem despoletou um conjunto de ensaios de pirólise com várias biomassas, lenhina e celulose, e temperaturas entre os 600 e 975ºC. Elevadas taxas de aquecimento do combustível foram alcançadas em reatores laboratoriais de leito fluidizado borbulhante e leito fixo, ao passo que um sistema termo-gravimétrico permitiu estudar o efeito de taxas de aquecimento mais baixas. Os resultados mostram que, em condições típicas de processos de combustão e gasificação, a quantidade de voláteis libertada da biomassa é pouco influenciada pela temperatura do reator mas varia bastante entre combustíveis. Uma análise mais aprofundada deste assunto permitiu mostrar que o rendimento de carbonizado está intimamente relacionado com o rácio O/C do combustível original, sendo proposto um modelo simples para descrever esta relação. Embora a quantidade total de voláteis libertada seja estabelecida pela composição da biomassa, a respetiva composição química depende bastante da temperatura do reator. Rendimentos de espécies condensáveis (água e espécies orgânicas), CO2 e hidrocarbonetos leves descrevem um máximo relativamente à temperatura para dar lugar a CO e H2 às temperaturas mais altas. Não obstante, em certas gamas de temperatura, os rendimentos de algumas das principais espécies gasosas (e.g. CO, H2, CH4) estão bem correlacionados entre si, o que permitiu desenvolver modelos empíricos que minimizam o efeito das condições operatórias e, ao mesmo tempo, realçam o efeito do combustível na composição do gás. Em suma, os ensaios de pirólise realizados neste trabalho permitiram constatar que a estequiometria da pirólise de biomassa se relaciona de várias formas com a composição elementar do combustível original o que levanta várias possibilidades para a avaliação e projeto de processos de combustão e gasificação de biomassa.

Conversão de veículos diesel para tração elétrica

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Load Control Timescales Simulation in a Multi-Agent Smart Grid Platform

Environmental concerns and the shortage in the fossil fuel reserves have been potentiating the growth and globalization of distributed generation. Another resource that has been increasing its importance is the demand response, which is used to change consumers’ consumption profile, helping to reduce peak demand. Aiming to support small players’ participation in demand response events, the Curtailment Service Provider emerged. This player works as an aggregator for demand response events. The control of small and medium players which act in smart grid and micro grid environments is enhanced with a multi-agent system with artificial intelligence techniques – the MASGriP (Multi-Agent Smart Grid Platform). Using strategic behaviours in each player, this system simulates the profile of real players by using software agents. This paper shows the importance of modeling these behaviours for studying this type of scenarios. A case study with three examples shows the differences between each player and the best behaviour in order to achieve the higher profit in each situation.

PV inverters for module level applications

Dissertação para obtenção do Grau de Mestre em Energias Renováveis – Conversão Eléctrica e Utilização Sustentáveis

Post-merger innovative performance in the renewable energy sector

Due to global warming and shrinking fossil fuel resources, politics as well as society urge for a reduction of green house gas (GHG) emissions. This leads to a re-orientation towards a renewable energy sector. In this context, innovation and new technologies are key success factors. Moreover, the renewable energy sector has entered a consolidation stage, where corporate investors and mergers and acquisitions (M&A) gain in importance. Although both M&A and innovation in the renewable energy sector are important corporate strategies, the link between those two aspects has not been examined before. The present thesis examines the research question how M&A influence the acquirer’s post-merger innovative performance in the renewable energy sector. Based on a framework of relevant literature, three hypotheses are defined. First, the relation between non-technology oriented M&A and post-merger innovative performance is discussed. Second, the impact of absolute acquired knowledge on postmerger innovativeness is examined. Third, the target-acquirer relatedness is discussed. A panel data set of 117 firms collected over a period of six years has been analyzed via a random effects negative binomial regression model and a time lag of one year. The results support a non-significant, negative impact of non-technology M&A on postmerger innovative performance. The applied model did not support a positive and significant impact of absolute acquired knowledge on post-merger innovative performance. Lastly, the results suggest a reverse relation than postulated by Hypothesis 3. Targets from the same industry significantly and negatively influence the acquirers’ innovativeness.

Improving the microbial production of biofuels through metabolic engineering

Les défis conjoints du changement climatique d'origine anthropique et la diminution des réserves de combustibles fossiles sont le moteur de recherche intense pour des sources d'énergie alternatives. Une avenue attrayante est d'utiliser un processus biologique pour produire un biocarburant. Parmi les différentes options en matière de biocarburants, le bio-hydrogène gazeux est un futur vecteur énergétique attrayant en raison de son efficacité potentiellement plus élevé de conversion de puissance utilisable, il est faible en génération inexistante de polluants et de haute densité d'énergie. Cependant, les faibles rendements et taux de production ont été les principaux obstacles à l'application pratique des technologies de bio-hydrogène. Des recherches intensives sur bio-hydrogène sont en cours, et dans les dernières années, plusieurs nouvelles approches ont été proposées et étudiées pour dépasser ces inconvénients. À cette fin, l'objectif principal de cette thèse était d'améliorer le rendement en hydrogène moléculaire avec un accent particulier sur l'ingénierie métabolique et l’utilisation de bioprocédés à variables indépendantes. Une de nos hypothèses était que la production d’hydrogène pourrait être améliorée et rendue plus économiquement viable par ingénierie métabolique de souches d’Escherichia coli producteurs d’hydrogène en utilisant le glucose ainsi que diverses autres sources de carbone, y compris les pentoses. Les effets du pH, de la température et de sources de carbone ont été étudiés. La production maximale d'hydrogène a été obtenue à partir de glucose, à un pH initial de 6.5 et une température de 35°C. Les études de cinétiques de croissance ont montré que la μmax était 0.0495 h-1 avec un Ks de 0.0274 g L-1 lorsque le glucose est la seule source de carbone en milieu minimal M9. .Parmi les nombreux sucres et les dérivés de sucres testés, les rendements les plus élevés d'hydrogène sont avec du fructose, sorbitol et D-glucose; 1.27, 1.46 et 1.51 mol H2 mol-1 de substrat, respectivement. En outre, pour obtenir les interactions entre les variables importantes et pour atteindre une production maximale d'hydrogène, un design 3K factoriel complet Box-Behnken et la méthodologie de réponse de surface (RSM) ont été employées pour la conception expérimentale et l'analyse de la souche d'Escherichia coli DJT135. Le rendement en hydrogène molaire maximale de 1.69 mol H2 mol-1 de glucose a été obtenu dans les conditions optimales de 75 mM de glucose, à 35°C et un pH de 6.5. Ainsi, la RSM avec un design Box-Behken était un outil statistique utile pour atteindre des rendements plus élevés d'hydrogène molaires par des organismes modifiés génétiquement. Ensuite, l'expression hétérologue de l’hydrogénases soluble [Ni-Fe] de Ralstonia eutropha H16 (l'hydrogénase SH) a tenté de démontrer que la mise en place d'une voie capable de dériver l'hydrogène à partir de NADH pourrait surpasser le rendement stoechiométrique en hydrogène.. L’expression a été démontrée par des tests in vitro de l'activité enzymatique. Par ailleurs, l'expression de SH a restaurée la croissance en anaérobie de souches mutantes pour adhE, normalement inhibées en raison de l'incapacité de réoxyder le NADH. La mesure de la production d'hydrogène in vivo a montré que plusieurs souches modifiées métaboliquement sont capables d'utiliser l'hydrogénase SH pour dériver deux moles d’hydrogène par mole de glucose consommé, proche du maximum théorique. Une autre stratégie a montré que le glycérol brut pourrait être converti en hydrogène par photofermentation utilisant Rhodopseudomonas palustris par photofermentation. Les effets de la source d'azote et de différentes concentrations de glycérol brut sur ce processus ont été évalués. À 20 mM de glycérol, 4 mM glutamate, 6.1 mol hydrogène / mole de glycérol brut ont été obtenus dans des conditions optimales, un rendement de 87% de la théorie, et significativement plus élevés que ce qui a été réalisé auparavant. En prolongement de cette étude, l'optimisation des paramètres a également été utilisée. Dans des conditions optimales, une intensité lumineuse de 175 W/m2, 30 mM glycérol et 4.5 mM de glutamate, 6.69 mol hydrogène / mole de glycérol brut ont été obtenus, soit un rendement de 96% de la valeur théorique. La détermination de l'activité de la nitrogénase et ses niveaux d'expression ont montré qu'il y avait relativement peu de variation de la quantité de nitrogénase avec le changement des variables alors que l'activité de la nitrogénase variait considérablement, avec une activité maximale (228 nmol de C2H4/ml/min) au point central optimal. Dans la dernière section, la production d'hydrogène à partir du glucose via la photofermentation en une seule étape a été examinée avec la bactérie photosynthétique Rhodobacter capsulatus JP91 (hup-). La méthodologie de surface de réponse avec Box-Behnken a été utilisée pour optimiser les variables expérimentales de façon indépendante, soit la concentration de glucose, la concentration du glutamate et l'intensité lumineuse, ainsi que d'examiner leurs effets interactifs pour la maximisation du rendement en hydrogène moléculaire. Dans des conditions optimales, avec une intensité lumineuse de 175 W/m2, 35 mM de glucose, et 4.5 mM de glutamate,, un rendement maximal d'hydrogène de 5.5 (± 0.15) mol hydrogène /mol glucose, et un maximum d'activité de la nitrogénase de 246 (± 3.5) nmol C2H4/ml/min ont été obtenus. L'analyse densitométrique de l'expression de la protéine-Fe nitrogenase dans les différentes conditions a montré une variation significative de l'expression protéique avec un maximum au point central optimisé. Même dans des conditions optimales pour la production d'hydrogène, une fraction significative de la protéine Fe a été trouvée dans l'état ADP-ribosylée, suggérant que d'autres améliorations des rendements pourraient être possibles. À cette fin, un mutant amtB dérivé de Rhodobacter capsulatus JP91 (hup-) a été créé en utilisant le vecteur de suicide pSUP202. Les résultats expérimentaux préliminaires montrent que la souche nouvellement conçue métaboliquement, R. capsulatus DG9, produit 8.2 (± 0.06) mol hydrogène / mole de glucose dans des conditions optimales de cultures discontinues (intensité lumineuse, 175 W/m2, 35 mM de glucose et 4.5 mM glutamate). Le statut d'ADP-ribosylation de la nitrogénase-protéine Fe a été obtenu par Western Blot pour la souche R. capsulatus DG9. En bref, la production d'hydrogène est limitée par une barrière métabolique. La principale barrière métabolique est due au manque d'outils moléculaires possibles pour atteindre ou dépasser le rendement stochiométrique en bio-hydrogène depuis les dernières décennies en utilisant les microbes. À cette fin, une nouvelle approche d’ingénierie métabolique semble très prometteuse pour surmonter cette contrainte vers l'industrialisation et s'assurer de la faisabilité de la technologie de la production d'hydrogène. Dans la présente étude, il a été démontré que l’ingénierie métabolique de bactéries anaérobiques facultatives (Escherichia coli) et de bactéries anaérobiques photosynthétiques (Rhodobacter capsulatus et Rhodopseudomonas palustris) peuvent produire de l'hydrogène en tant que produit majeur à travers le mode de fermentation par redirection métabolique vers la production d'énergie potentielle. D'autre part, la méthodologie de surface de réponse utilisée dans cette étude représente un outil potentiel pour optimiser la production d'hydrogène en générant des informations appropriées concernant la corrélation entre les variables et des producteurs de bio-de hydrogène modifiés par ingénierie métabolique. Ainsi, un outil d'optimisation des paramètres représente une nouvelle avenue pour faire un pont entre le laboratoire et la production d'hydrogène à l'échelle industrielle en fournissant un modèle mathématique potentiel pour intensifier la production de bio-hydrogène. Par conséquent, il a été clairement mis en évidence dans ce projet que l'effort combiné de l'ingénierie métabolique et la méthodologie de surface de réponse peut rendre la technologie de production de bio-hydrogène potentiellement possible vers sa commercialisation dans un avenir rapproché.

Isolation and identification of native microalgae for biodiesel production

La demande croissante en carburants, ainsi que les changements climatiques dus au réchauffement planétaire poussent le monde entier à chercher des sources d’énergie capables de produire des combustibles alternatifs aux combustibles fossiles. Durant les dernières années, plusieurs sources potentielles ont été identifiées, les premières à être considérées sont les plantes oléagineuses comme source de biocarburant, cependant l’utilisation de végétaux ou d’huiles végétales ayant un lien avec l’alimentation humaine peut engendrer une hausse des prix des denrées alimentaires, sans oublier les questions éthiques qui s’imposent. De plus, l'usage des huiles non comestibles comme sources de biocarburants, comme l’huile de jatropha, de graines de tabac ou de jojoba, révèle un problème de manque de terre arable ce qui oblige à réduire les terres cultivables de l'industrie agricole et alimentaire au profit des cultures non comestibles. Dans ce contexte, l'utilisation de microorganismes aquatiques, tels que les microalgues comme substrats pour la production de biocarburant semble être une meilleure solution. Les microalgues sont faciles à cultiver et peuvent croitre avec peu ou pas d'entretien. Elles peuvent ainsi se développer dans des eaux douces, saumâtres ou salées de même que dans les terres non cultivables. Le rendement en lipide peut être largement supérieur aux autres sources de biocarburant potentiel, sans oublier qu’elles ne sont pas comestibles et sans aucun impact sur l'industrie alimentaire. De plus, la culture intensive de microalgues pour la production de biodiesel pourrait également jouer un rôle important dans l'atténuation des émissions de CO2. Dans le cache de ce travail, nous avons isolé et identifié morphologiquement des espèces de microalgues natives du Québec, pour ensuite examiner et mesurer leur potentiel de production de lipides (biodiesel). L’échantillonnage fut réalisé dans trois régions différentes du Québec: la région de Montréal, la gaspésie et le nord du Québec, et dans des eaux douces, saumâtres ou salées. Cent souches ont été isolées à partir de la région de Montréal, caractérisées et sélectionnées selon la teneur en lipides et leur élimination des nutriments dans les eaux usées à des températures différentes (10 ± 2°C et 22 ± 2°C). Les espèces ayant une production potentiellement élevée en lipides ont été sélectionnées. L’utilisation des eaux usées, comme milieu de culture, diminue le coût de production du biocarburant et sert en même temps d'outil pour le traitement des eaux usées. Nous avons comparé la biomasse et le rendement en lipides des souches cultivées dans une eau usée par apport à ceux dans un milieu synthétique, pour finalement identifié un certain nombre d'isolats ayant montré une bonne croissance à 10°C, voir une teneur élevée en lipides (allant de 20% à 45% du poids sec) ou une grande capacité d'élimination de nutriment (>97% d'élimination). De plus, nous avons caractérisé l'une des souches intéressantes ayant montré une production en lipides et une biomasse élevée, soit la microalgue Chlorella sp. PCH90. Isolée au Québec, sa phylogénie moléculaire a été établie et les études sur la production de lipides en fonction de la concentration initiale de nitrate, phosphate et chlorure de sodium ont été réalisées en utilisant de la méthodologie des surfaces de réponse. Dans les conditions appropriées, cette microalgue pourrait produire jusqu'à 36% de lipides et croitre à la fois dans un milieu synthétique et un milieu issu d'un flux secondaire de traitement des eaux usées, et cela à 22°C ou 10°C. Ainsi, on peut conclure que cette souche est prometteuse pour poursuivre le développement en tant que productrice potentielle de biocarburants dans des conditions climatiques locales.

Le toit comme outil de régulation environnementale : le cas montréalais.

Cette recherche s’inscrit dans le cadre du programme interdisciplinaire de recherche Ignis Mutat Res et vise à éclairer l’univers de l’architecture sur la capacité des toits à amener des solutions efficaces aux problématiques environnementales dans un contexte urbain dense et à forte consommation d'énergie. La volonté de réduire l’empreinte écologique des villes est aujourd’hui bien présente dans le monde de la recherche architecturale et urbaine, ayant ainsi fait preuve de son importance. Pourtant, la réduction de l’empreinte écologique des villes serait une approche globale difficile à quantifier économiquement. Le manque de méthodologie standardisée fait en sorte que les travaux sur le sujet empruntent des démarches qui ne dépassent pas l’étape exploratoire. Dans ce contexte, le mémoire porte sur l’élaboration d’un dispositif numérique d’évaluation des potentialités des toits horizontaux comme un outil d’aide à la décision pour les interventions urbaines visant à réduire l’empreinte écologique des villes, en utilisant le cas de Montréal. Ce type de toit est abordé comme un territoire d’investigation en contribution aux préoccupations reliées à la gestion de l’eau et à l’atténuation des îlots de chaleur. Plus précisément, cette recherche porte sur trois secteurs de l'île de Montréal. Ces échantillons correspondent à deux types de formes urbaines (résidentielle versus commerciale ou industrielle) et sont décortiqués dans le but d’identifier les déséquilibres entre les espaces naturels, faisant référence aux espaces verts (jardins, parcs et canopées) et les étendues minérales occasionnées par l'urbanisation. Ces rapports exprimés en superficies démontrent que l’étendue des toits est assez considérable pour compenser le manque d’espaces naturels en ville. La végétalisation des toits à l’échelle d’un secteur pourrait donc atténuer considérablement les problèmes environnementaux liés aux îlots de chaleur et à la gestion du ruissellement des eaux de pluie. La stratégie consistant à explorer l'hypothèse des 50 % de naturel versus 50 % de minéral pourrait contribuer grandement à l’autonomisation des villes et à la diminution de leurs dépendances vis-à-vis des ressources fossiles.

Studies on lipid production of microalgae under mixotrophic growth, utilizing glycerol as a carbon source, combined with nitrogen starvation

Rampant increases in oil prices and detrimental effects of fossil fuels on the environment have been the main impetus for the development of environmentally friendly and sustainable energy sources. Amongst the many possibilities, microalgae have been proposed as a new alternative energy source to fossil fuels, as their growth is both sustainable and ecologically safe. By definition, microalgae are unicellular photosynthetic microorganisms containing chlorophyll a. These organisms are capable of producing large quantities of oils, surpassing that of traditional oil-seed crops, which can be transformed, through chemical processes, into biofuels such as biodiesel or bio-gasoline. Thus, recent research has gone into discovering high lipid producing algal strains, optimising growth media for increased lipid production and developing metabolic engineering to make microalgae a source of biofuel that is competitive to more traditional sources of biofuel and even to fossil fuel. In this context, the research reported here focused on using a mixotrophic growth mode as a way to increase lipid production for certain strains of microalgae. In addition, nitrogen starvation combined with mixotrophy was studied to analyse its effects on lipid production. Mixotrophy is the parallel usage of two trophic modes, in our case photoautotrophy and heterotrophy. Consequently, 12 algal strains were screened for mixotrophic growth, using glycerol as a carbon source. Glycerol is a waste product of the current biodiesel industry; it is a cheap and abundant carbon source present in many metabolic pathways. From this initial screening, several strains were chosen for subsequent experiments involving nitrogen starvation. Nitrogen starvation has been shown to induce lipid accumulation. The results obtained show that a mixotrophic growth mode, using glycerol as a carbon source, enhances lipid production for certain strains. Moreover, lipid enhancement was shown for nitrogen starvation combined with mixotrophic growth mode. This was dependant on time spent under nitrogen starvation and on initial concentrations of the nitrogen source.

Assessment of Energy Conservation in Indian Cement Industry and Forecasting of Co2 Emissions

Cement industry ranks 2nd in energy consumption among the industries in India. It is one of the major emitter of CO2, due to combustion of fossil fuel and calcination process. As the huge amount of CO2 emissions cause severe environment problems, the efficient and effective utilization of energy is a major concern in Indian cement industry. The main objective of the research work is to assess the energy cosumption and energy conservation of the Indian cement industry and to predict future trends in cement production and reduction of CO2 emissions. In order to achieve this objective, a detailed energy and exergy analysis of a typical cement plant in Kerala was carried out. The data on fuel usage, electricity consumption, amount of clinker and cement production were also collected from a few selected cement industries in India for the period 2001 - 2010 and the CO2 emissions were estimated. A complete decomposition method was used for the analysis of change in CO2 emissions during the period 2001 - 2010 by categorising the cement industries according to the specific thermal energy consumption. A basic forecasting model for the cement production trend was developed by using the system dynamic approach and the model was validated with the data collected from the selected cement industries. The cement production and CO2 emissions from the industries were also predicted with the base year as 2010. The sensitivity analysis of the forecasting model was conducted and found satisfactory. The model was then modified for the total cement production in India to predict the cement production and CO2 emissions for the next 21 years under three different scenarios. The parmeters that influence CO2 emissions like population and GDP growth rate, demand of cement and its production, clinker consumption and energy utilization are incorporated in these scenarios. The existing growth rate of the population and cement production in the year 2010 were used in the baseline scenario. In the scenario-1 (S1) the growth rate of population was assumed to be gradually decreasing and finally reach zero by the year 2030, while in scenario-2 (S2) a faster decline in the growth rate was assumed such that zero growth rate is achieved in the year 2020. The mitigation strategiesfor the reduction of CO2 emissions from the cement production were identified and analyzed in the energy management scenarioThe energy and exergy analysis of the raw mill of the cement plant revealed that the exergy utilization was worse than energy utilization. The energy analysis of the kiln system showed that around 38% of heat energy is wasted through exhaust gases of the preheater and cooler of the kiln sysetm. This could be recovered by the waste heat recovery system. A secondary insulation shell was also recommended for the kiln in the plant in order to prevent heat loss and enhance the efficiency of the plant. The decomposition analysis of the change in CO2 emissions during 2001- 2010 showed that the activity effect was the main factor for CO2 emissions for the cement industries since it is directly dependent on economic growth of the country. The forecasting model showed that 15.22% and 29.44% of CO2 emissions reduction can be achieved by the year 2030 in scenario- (S1) and scenario-2 (S2) respectively. In analysing the energy management scenario, it was assumed that 25% of electrical energy supply to the cement plants is replaced by renewable energy. The analysis revealed that the recovery of waste heat and the use of renewable energy could lead to decline in CO2 emissions 7.1% for baseline scenario, 10.9 % in scenario-1 (S1) and 11.16% in scenario-2 (S2) in 2030. The combined scenario considering population stabilization by the year 2020, 25% of contribution from renewable energy sources of the cement industry and 38% thermal energy from the waste heat streams shows that CO2 emissions from Indian cement industry could be reduced by nearly 37% in the year 2030. This would reduce a substantial level of greenhouse gas load to the environment. The cement industry will remain one of the critical sectors for India to meet its CO2 emissions reduction target. India’s cement production will continue to grow in the near future due to its GDP growth. The control of population, improvement in plant efficiency and use of renewable energy are the important options for the mitigation of CO2 emissions from Indian cement industries

Master Plan for Renewable Energy based Electricity Generation in The Gambia

The principal objective of this paper is to develop a methodology for the formulation of a master plan for renewable energy based electricity generation in The Gambia, Africa. Such a master plan aims to develop and promote renewable sources of energy as an alternative to conventional forms of energy for generating electricity in the country. A tailor-made methodology for the preparation of a 20-year renewable energy master plan focussed on electricity generation is proposed in order to be followed and verified throughout the present dissertation, as it is applied for The Gambia. The main input data for the proposed master plan are (i) energy demand analysis and forecast over 20 years and (ii) resource assessment for different renewable energy alternatives including their related power supply options. The energy demand forecast is based on a mix between Top-Down and Bottom-Up methodologies. The results are important data for future requirements of (primary) energy sources. The electricity forecast is separated in projections at sent-out level and at end-user level. On the supply side, Solar, Wind and Biomass, as sources of energy, are investigated in terms of technical potential and economic benefits for The Gambia. Other criteria i.e. environmental and social are not considered in the evaluation. Diverse supply options are proposed and technically designed based on the assessed renewable energy potential. This process includes the evaluation of the different available conversion technologies and finalizes with the dimensioning of power supply solutions, taking into consideration technologies which are applicable and appropriate under the special conditions of The Gambia. The balance of these two input data (demand and supply) gives a quantitative indication of the substitution potential of renewable energy generation alternatives in primarily fossil-fuel-based electricity generation systems, as well as fuel savings due to the deployment of renewable resources. Afterwards, the identified renewable energy supply options are ranked according to the outcomes of an economic analysis. Based on this ranking, and other considerations, a 20-year investment plan, broken down into five-year investment periods, is prepared and consists of individual renewable energy projects for electricity generation. These projects included basically on-grid renewable energy applications. Finally, a priority project from the master plan portfolio is selected for further deeper analysis. Since solar PV is the most relevant proposed technology, a PV power plant integrated to the fossil-fuel powered main electrical system in The Gambia is considered as priority project. This project is analysed by economic competitiveness under the current conditions in addition to sensitivity analysis with regard to oil and new-technology market conditions in the future.

More than irrigation - The Balinese Subak system as a unique form of cooperative water resource management in Indonesia

For over 1,000 years, the Balinese have developed a unique system of democratic and sustainable water irrigation. It has shaped the cultural landscapes of Bali and enables local communities to manage the ecology of terraced rice fields at the scale of whole watersheds. The Subak system has made the Balinese the most productive rice growers in Indonesia and ensures a high level of food sovereignty for a dense population on the volcanic island. The Subak system provides a vibrant example of a diverse, ecologically sustainable, economically productive and democratic water management system that is also characterized by its nonreliance on fossil fuel derivatives or heavy machinery. In 2012, UNESCO has recognized five rice terraces and their water temples as World Heritage site and supports its conservation and protection. However, the fragile Subak system is threatened for its complexity and interconnectedness by new agricultural practices and increasing tourism on the island.

Integrated bioenergy and food production

Rising global energy needs and limited fossil fuel reserves have led to increased use of renewable energies. In Germany, this has entailed massive exploitation of agricultural biomass for biogas generation, associated with unsustainable farming practices. Organic agriculture not only reduces negative environmental impacts, organic farmers were also prime movers in anaerobic digestion (AD) in Germany. This study’s aim was to identify the structure, development, and characteristics of biogas production associated with organic farming systems in order to estimate further development, as well as energetic and associated agronomic potentials. Surveys were conducted among organic farms with AD technology. 144 biogas plants could be included in the analysis. Total installed electrical capacity was 30.8 MWel, accounting for only 0.8% of the total installed electrical capacity in the German biogas sector. Recently, larger plant types (>250 kWel) with increased use of (also purchased) energy crops have emerged. Farmers noticed increases in yields (22% on average) and quality of cash crops in arable farming through integrated biogas production. In conclusion, although the share of AD in organic farming is relatively small it can provide various complementary socio-ecological benefits such as the enhancement of food output through digestate fertilization without additional need for land, while simultaneously reducing greenhouse gas emissions from livestock manures and soils. However, to achieve this eco-functional intensification, AD systems and their management have to be well adapted to farm size and production focus and based primarily on residue biomass.

An integrated assessment of carbon dioxide capture and storage in the UK

Geological carbon dioxide storage (CCS) has the potential to make a significant contribution to the decarbonisation of the UK. Amid concerns over maintaining security, and hence diversity, of supply, CCS could allow the continued use of coal, oil and gas whilst avoiding the CO2 emissions currently associated with fossil fuel use. This project has explored some of the geological, environmental, technical, economic and social implications of this technology. The UK is well placed to exploit CCS with a large offshore storage capacity, both in disused oil and gas fields and saline aquifers. This capacity should be sufficient to store CO2 from the power sector (at current levels) for a least one century, using well understood and therefore likely to be lower-risk, depleted hydrocarbon fields and contained parts of aquifers. It is very difficult to produce reliable estimates of the (potentially much larger) storage capacity of the less well understood geological reservoirs such as non-confined parts of aquifers. With the majority of its large coal fired power stations due to be retired during the next 15 to 20 years, the UK is at a natural decision point with respect to the future of power generation from coal; the existence of both national reserves and the infrastructure for receiving imported coal makes clean coal technology a realistic option. The notion of CCS as a ‘bridging’ or ‘stop-gap’ technology (i.e. whilst we develop ‘genuinely’ sustainable renewable energy technologies) needs to be examined somewhat critically, especially given the scale of global coal reserves. If CCS plant is built, then it is likely that technological innovation will bring down the costs of CO2 capture, such that it could become increasingly attractive. As with any capitalintensive option, there is a danger of becoming ‘locked-in’ to a CCS system. The costs of CCS in our model for UK power stations in the East Midlands and Yorkshire to reservoirs in the North Sea are between £25 and £60 per tonne of CO2 captured, transported and stored. This is between about 2 and 4 times the current traded price of a tonne of CO2 in the EU Emissions Trading Scheme. In addition to the technical and economic requirements of the CCS technology, it should also be socially and environmentally acceptable. Our research has shown that, given an acceptance of the severity and urgency of addressing climate change, CCS is viewed favourably by members of the public, provided it is adopted within a portfolio of other measures. The most commonly voiced concern from the public is that of leakage and this remains perhaps the greatest uncertainty with CCS. It is not possible to make general statements concerning storage security; assessments must be site specific. The impacts of any potential leakage are also somewhat uncertain but should be balanced against the deleterious effects of increased acidification in the oceans due to uptake of elevated atmospheric CO2 that have already been observed. Provided adequate long term monitoring can be ensured, any leakage of CO2 from a storage site is likely to have minimal localised impacts as long as leaks are rapidly repaired. A regulatory framework for CCS will need to include risk assessment of potential environmental and health and safety impacts, accounting and monitoring and liability for the long term. In summary, although there remain uncertainties to be resolved through research and demonstration projects, our assessment demonstrates that CCS holds great potential for significant cuts in CO2 emissions as we develop long term alternatives to fossil fuel use. CCS can contribute to reducing emissions of CO2 into the atmosphere in the near term (i.e. peak-shaving the future atmospheric concentration of CO2), with the potential to continue to deliver significant CO2 reductions over the long term.

Controls of carbon dioxide concentrations and fluxes above central London

Eddy-covariance measurements of carbon dioxide fluxes were taken semi-continuously between October 2006 and May 2008 at 190 m height in central London (UK) to quantify emissions and study their controls. Inner London, with a population of 8.2 million (~5000 inhabitants per km2) is heavily built up with 8% vegetation cover within the central boroughs. CO2 emissions were found to be mainly controlled by fossil fuel combustion (e.g. traffic, commercial and domestic heating). The measurement period allowed investigation of both diurnal patterns and seasonal trends. Diurnal averages of CO2 fluxes were found to be highly correlated to traffic. However changes in heating-related natural gas consumption and, to a lesser extent, photosynthetic activity that controlled the seasonal variability. Despite measurements being taken at ca. 22 times the mean building height, coupling with street level was adequate, especially during daytime. Night-time saw a higher occurrence of stable or neutral stratification, especially in autumn and winter, which resulted in data loss in post-processing. No significant difference was found between the annual estimate of net exchange of CO2 for the expected measurement footprint and the values derived from the National Atmospheric Emissions Inventory (NAEI), with daytime fluxes differing by only 3%. This agreement with NAEI data also supported the use of the simple flux footprint model which was applied to the London site; this also suggests that individual roughness elements did not significantly affect the measurements due to the large ratio of measurement height to mean building height.