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Bio-oil which is produced by fast pyrolysis of biomass has high energy density compared to as received biomass. Two cases are studied for pipeline transport of bio-oil, a coal-based and hydro power based electricity supplies. These cases of pipeline transport are compared to two cases of truck transport (trailer and super B-train truck). The life cycle GHG emissions from the pipeline transport of bio-oil for the two sources of electricity are 345 and 17 g of CO2 m-3 km-1. The emissions for transport by trailer and super B-train truck are 89 and 60 g of CO2 m-3 km-1. Energy input for bio-oil transport is 3.95 MJ m-3 km-1 by pipeline, 2.59 MJ m-3 km-1 by trailer, and 1.66 MJ m-3 km-1 by super B-train truck. The results show that GHG emissions in pipeline transport are largely dependent on the source of electricity; substituting 250 m3 day-1 of pipeline-transported bio-oil for coal can mitigate about 5.1 million tonnes of CO2 per year in the production of electricity. The fixed and variable components of cost are 0.0423 $/m3 and 0.1201 $/m3/km at a pipeline capacity of 560 m3/day and for a distance of 100. It costs less to transport bio-oil by pipeline than by trailer and super B-train tank trucks at pipeline capacities of 1,000 and 1,700 m3/day, and for a transportation distance of 100 km. Power from pipeline-transported bio-oil is expensive than power that is produced by direct combustion of wood chips and transmitted through electric lines.

<p>Renewable energy adoption is critical when considering future energy grids and how they impact the environment, economy and society. While fossil fuels have traditionally been employed to generate the electricity used across every facet of the global economy, renewables are becoming increasingly more attractive as a substitute. Fossil fuels have historically outperformed their clean energy counterparts in terms of levelized cost. However, over the last few decades renewables have become extremely cost competitive and are starting to outpace their opposition as advancements in technology continue. As the cost gap between “brown” and “green” energy sources decreases, energy grid mixes will adopt more sustainably responsible generation, positively impacting the planet.</p> <p>In the following thesis, two studies are presented which demonstrate new innovations for decreasing the cost of offshore wind energy and how renewables and desalination can be integrated along the US-Mexico border. The first study describes an itemized breakdown of how substituting the mechanical transmission with hydraulics can lower the life-time cost of an offshore wind turbine. The second analysis details a complex wind and solar powered clean water production and distribution network to combat ongoing water scarcity along the US-Mexico border. Both concepts push the boundaries of scientific innovation and its application for solving social and economic issues. </p>

abstract: Concentrating Solar Power (CSP) plant technology can produce reliable and dispatchable electric power from an intermittent solar resource. Recent advances in thermochemical energy storage (TCES) can offer further improvements to increase off-sun operating hours, improve system efficiency, and the reduce cost of delivered electricity. This work describes a 111.7 MWe CSP plant with TCES using a mixed ionic-electronic conducting metal oxide, CAM28, as both the heat transfer and thermal energy storage media. Turbine inlet temperatures reach 1200 °C in the combined cycle power block. A techno-economic model of the CSP system is developed to evaluate design considerations to meet targets for low-cost and renewable power with 6-14 hours of dispatchable storage for off-sun power generation. Hourly solar insolation data is used for Barstow, California, USA. Baseline design parameters include a 6-hour storage capacity and a 1.8 solar multiple. Sensitivity analyses are performed to evaluate the effect of engineering parameters on total installed cost, generation capacity, and levelized cost of electricity (LCOE). Calculated results indicate a full-scale 111.7 MWe system at $274 million in installed cost can generate 507 GWh per year at a levelized cost of $0.071 per kWh. Expected improvements to design, performance, and costs illustrate options to reduce energy costs to less than $0.06 per kWh. / Dissertation/Thesis / Masters Thesis Civil, Environmental and Sustainable Engineering 2017

Solar heat pump systems (SHPs) are systems that combine solar energy and heat pumps. SHPs have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many solar thermal heat pump systems have become market-available in recent years; however these systems are still not widely employed in the residential sector. This is due mainly to the high initial costs (investment and installation costs) of solar thermal heat pump systems, which limits their cost-effectiveness. Enhancing cost-effectiveness of solar thermal heat pump systems is necessary for a more effective and broader market penetration. In this thesis, solar thermal and photovoltaic systems combined with heat pumps for heating applications are treated. The overall aims of the thesis are to: 1) investigate techno-economics of SHPs and 2) investigate possible solutions for improving system performance of a reference solar thermal and heat pump system for residential heating applications. In the first part of the thesis, the influence of climatic boundary conditions on economic performance of SHPs has been investigated by means of: a) an economic comparison of SHPs found in the relevant literature and b) system simulations of the reference solar thermal heat pump system. In the second part of the thesis, potential solutions for improving system performance of the reference solar thermal heat pump system with limited change in system’ costs are investigated. A systematic approach was used for investigating cost-effectiveness of the system improvements in the reference system. Based on results of the cost-effectiveness analysis, some of the investigated system improvements were chosen for being included in the design of a novel solar thermal and air source heat pump system concept. The novel system was designed for a house standard with relatively high operating temperatures (55°C/45°C) in the space heating distribution system and for high space heating demand (123 kWh/m2·year). Finally, the thesis ends with a cost-effectiveness analysis of the novel system. / <p>QC 20170918</p> / MacSheep / iNSPiRe

The use of biofuels as an alternative to gasoline in the transportation sector is seen by policy makers as an important strategy to reduce global greenhouse gas emissions. Biobutanol is one such biofuel that is gathering increasing attention in the biofuel community, because of its preferable fuel qualities over bioethanol. However, despite increasing research into biobutanol production, the thermochemical route for biobutanol production has not been adequately studied in the peer-reviewed literature. In light of this motivation, this thesis considers the design, and economic and environmental assessment of thermochemical plants for producing second and third generation biobutanol. In addition, the potential for using process intensification technology such as dividing wall columns (DWC) in place of conventional distillation columns is also investigated as a way to improve thermochemical biobutanol plants. As a first step, a novel thermochemical plant for producing second generation biobutanol is developed. Detailed economic analysis of this plant show that it is competitive with gasoline under certain process, and market conditions. The designed plant is then extended, with some modifications, to evaluate the economic and environmental potential of a thermochemical plant for producing third generation biobutanol from macroalgae. It was concluded from the results that the thermochemical route is preferable for producing second generation biobutanol over third generation biobutanol. The novel thermochemical plant design is then updated by using a kinetic model of a pilot-scale demonstrated catalyst to represent the critical mixed alcohol synthesis reaction step. This change allows optimal unreacted syngas recycle configurations for maximizing butanol yield to be established. Furthermore, integrating a DWC, designed using a methodology developed in the thesis, into the updated thermochemical plant leads to additional plant improvements. Overall, the work carried out in this thesis demonstrates that the thermochemical route is a viable option for producing second generation biobutanol. / Thesis / Doctor of Philosophy (PhD)

The focus of the research is on the development of the concept of floating flexible thin film arrays for renewable electricity generation, in marine and lacustrine application areas. This research was motivated by reliability issues from wave energy converters which are prone to large loads due to the environment which they are exposed in; a flexible system would not need to withstand these loads but simply yield to them. The solid state power take off is an advantage of photovoltaic (PV) technology which removes failure risks associated with mechanical machinery, and also potential environmental hazards such as hydraulic oil spillage. The novelty of this technology requires some development before it could even be considered feasible for large scale installation. Techno-economics are a big issue in electricity developments and need to be scoped in order to ensure that they would be cost-competitive in the market and with other technologies. Other more technical issues relate to the change in expected electrical yield due to the modulation of the PV array according to the waves and the electrical performance of the PVs when in wet conditions. Results from numerical modelling of the modulating arrays show that there is not expected variation in electrical yield at central latitudes (slightly positive), although at higher latitudes there could be considerable depreciation. With regards to the electrical performance a notable improvement was measured due to the cooling effect, slight decrease in performance was also estimated due to water absorption (of ~ 1.4%) within the panels. Overall results from both economic and technical analysis show the feasibility of the concept and that it is a possibility for future commercialisation.

L’architecture actuelle des réseaux d’accès radio n’est pas adaptée en terme de capacité à supporter l’accroissement continu du trafic dans les systèmes cellulaires 4G et au-delà. L’objectif de cette thèse est de proposer une architecture réseau générique, GeRoFAN (Generic Radio over Fiber Access Network) pour la fédération des stations de base des systèmes cellulaires de nouvelle génération (WiMAX, 4G LTE). Deux innovations technologiques majeures sont utilisées pour l’implémentation de l’architecture GeRoFAN: la radio-sur-fibre (RoF) et les modulateurs réflexifs éléctro-absorbants. La thèse vise aussi à concevoir pour l’architecture GeRoFAN un plan contrôle et un canal de signalisation adapté permettant le basculement des ressources radio, selon la fluctuation du trafic, entre un grand nombre de cellules réparties à l’échelle métropolitaine. Cependant, il a été bien avéré que la transmission optique de plusieurs canaux radios en utilisant la RoF analogique est assujettie à des multiples facteurs de dégradation physique altérant la qualité du signal de ces canaux et induisant une perte dans leur capacité de Shannon. L’originalité du plan de contrôle de GeRoFAN est de réaliser une affectation optimisée des canaux radios sur les porteuses optiques, grace au multiplexage par sous-porteuse (SCM), afin d’ajuster la capacité de Shannon dans chaque cellule radio à la charge de trafic à laquelle elle est soumise. A cet effet, une connaissance fine des contraintes physiques de la transmission RoF est requise pour le plan de contrôle. Cette connaissance est acquise par l’élaboration d’un modèle analytique des divers bruits de transmission du système GeRoFAN. Contrairement à des propositions comparables, le plan contrôle de GeRoFAN se doit d’être le plus transparent que possible à la technologie des systèmes radio concernés. Sa nature " MAC radio agnostique " vise à permettre, grâce au multiplexage en longueur d’onde et au routage optique WDM, la fédération de plusieurs opérateurs utilisant différentes technologies radio sur la même infrastructure. Plus généralement, avec la mutualisation de l’architecture GeRoFAN, le plan de contrôle permet de virtualiser les ressources radiofréquences et de promouvoir de nouveaux modèles économiques pour les opérateurs Télécoms. Le dernier volet de la thèse se focalise sur la valeur "business" du paradigme GeRoFAN. Les contours du nouveau éco-system d’affaire promu par GeRoFAN sont définis. Les motivations/attentes des différentes parties prenantes dans cet éco-system sont esquissées, les contraintes réglementaires et organisationnelles soulevées sont adressées afin d’assurer un déploiement sans heurts de GeRoFAN. Bien qu’exigeant un nouveau modèle réglementaire, il s’agit de mettre en évidence l’intérêt économique de la solution GeRoFAN, tout particulièrement en comparaison à la RoF digitale, à travers des études technico-économiques chiffrant les couts d’investissement (CapEx), les couts opérationnels (OpEx) et les possibles retours sur investissement. A cet effet, deux modèles économiques sont proposés mettant en évidence la valeur ajoutée de GeRoFAN tout au long de la chaine de valeur. / Current radio access networks architectures are not suited in terms of capacity and backhauling capabilities to fit the continuing traffic increase of 4G cellular systems. The objective of the thesis is to propose an innovative and generic mobile backhauling network architecture, called GeRoFAN (Generic Radio-over-Fiber Access Network), for next generation mobile systems (WiMAX, 4G LTE). Two major technological innovations are used to implement GeRo-FAN: analog Radio-over-Fiber (RoF) and reflective amplified absorption modulators. The aim of this thesis is to design for such an architecture an original Control Plane (CP) and a signaling channel enabling to balance radio resources between a set of neighboring cells at the access/metropolitan scale according to traffic fluctuations. The transmission of several radio frequencies by means of an analog RoF link suffers from several impairments that may degrade the capacity of the radio system. The originality of the GeRoFAN-CP consists in mapping radio frequencies with optical carriers by means of Sub-Carrier Multiplexing (SCM) in order to optimize the Shannon’s capacity within the various cells covered by the system according to the current traffic load. For that purpose, a deep analysis and modeling of the various physical layer impairments impacting the quality of the radio signal is carried out. Unlike comparable approaches, the GeRoFAN-CP is as independent as possible from the radio layer protocols. Thus, the "radio MAC-agnostic" nature of the GeRoFAN-CP enables to federate multiple operators using different radio technologies onto the same backhauling optical infrastructure. Subcarrier and wavelength division multiplexing (SCM/WDM) as well as WDM optical routing capabilities are exploited onto the GeRoFAN transparent architecture. More globally, the GeRoFAN-CP enables a form of "radio frequency virtualization" while promoting new business models for Telecom service providers. The last part of the thesis focuses on the business value of the GeRoFAN paradigm. The expectations of the different stake-holders and main regulatory/organizational entities that could be involved in the deployment of GeRoFAN infrastructures should be addressed in order to achieve a smooth deployment of this new type of mobile backhauling. Economics of the GeRoFAN architecture are investigated in terms of OpEx/CapEx valuation and investment profitability, especially in reference to digitized RoF. Two business models are then proposed to study how GeRoFAN contributes to enriching the cellular backhauling service value chain.

<p dir="ltr">As the demand for energy rises and the threat of climate change looms, the need for clean, reliable, and affordable energy solutions like renewable energies has been more crucial. Energy storage systems (ESSs) are indispensable in addressing the intermittent nature of renewable energies and optimizing grid efficiency. Redox flow batteries (RFBs), thanks to their scalability, independent energy and power, swift response time, and minimal environmental impact, are a particularly promising ESS technology for long-duration storage applications. Despite the technological maturity of aqueous RFBs, nonaqueous organic RFBs (NAORFBs) are a prospective solution due to their wider operational voltage, potentially higher energy density, and larger pool of redox-active materials. However, the current state-of-the-art NAORFBs face challenges due to the lack of suitable organic redox-active materials (ORMs).</p><p dir="ltr">Despite the development of new materials, how their variables influence the total system cost of RFBs remains an unsolved challenge. With this regard, we established a techno-economic (TE) model to calculate the capital cost of nonaqueous hybrid RFBs (NAHRFBs). Prior to this work, NAHRFBs, which employs lithium metal as the anode, were regarded as an RFB system with the highest energy density. However, the correlation between their features and the system cost remained unclear, leaving a research gap for new ORMs. In our model, we selected a state-of-the-art NAHRFB system where 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) serves as the catholyte and lithium metal functions as the anode. Thereafter, sensitivity analyses identified several key factors that determine the system cost, including operational current density, area-specific resistance, cell voltage, electrolyte composition, and both the price and equivalent molecular weight of the ORM. To enhance the cost-competitiveness of current NAHRFBs, it is advised to increase the current density by 10 times and modulate the ORM-related characteristics. The virtually optimized condition manifests that the system cost of NAHRFB can meet the long-term cost target set by the U. S. Department of Energy.</p><p dir="ltr">Informed by the TE model, we discovered that elevating the oxidation potential of catholyte ORMs is instrumental in reducing the system cost of RFBs. To explore this possibility, we incorporated fluorine atoms, a potent electron-withdrawing group (EWG), into a dimethoxybenzene (DMB) derivative, yielding a new ORM (ANL-C46) with an oxidation potential enhanced by ~0.41 V. Surprisingly, ANL-C46 demonstrated superior kinetic and electrochemical stability compared to its parent molecule, as indicated by electron paramagnetic resonance (EPR) study and bulk electrolysis. In particular, the cycling performance of ANL-46 during the bulk electrolysis outperformed most reported high-potential (> 1 V vs. Ag/Ag⁺) ORMs. Density functional theory (DFT) calculations reveals that the introduced fluorine substituents suppress the typical side reaction pathways of the DMB series. These findings offer valuable insights into molecular engineering strategies that concurrently improve multiple desired ORM properties.</p><p dir="ltr">The stability of ORMs is critical for ensuring the extended lifetime of RFBs. We conducted a systematic exploration of the conjugation effect, which potentially stabilizes the ORMs by facilitating a more homogeneous distribution of delocalized charges. This was applied to tailor the electrochemical and physical properties of several DMB derivatives with varying aromatic ring counts. As we extended the aromatic core from 1,4-dimethoxybenzene (1,4-DMB) to 1,4-dimethoxynaphthalene (1,4-DMN), we noted a decrease in oxidation potential, enhanced kinetic stability, and an extended cycling life. However, further extending the aromatic core to 2-ethyl-9,10-dimethyanthracene (EDMA) results in rapid dealkylation of the radical cation due to increased strain in the methoxy substituents. Additionally, 1,4-DMN shows cross-reactions between radical cations, likely via disproportionation. This study demonstrates that extending the π-conjugation changes reactivity in multiple ways. Therefore, attempts to lower oxidation potential and improve ORMs stability through π-conjugation should be pursued with caution.</p>

The European Green Deal declared that Europe must decarbonize to become carbon-neutral within 2050. To do so, the European Parliament emphasized hydrogen as a major tool for energy transition. In regard of current environmental challenges, liquid hydrogen has raised interest as energy carrier for energy storage and transport. Due to growing use of renewable energy sources such as solar and wind energy, intermittent sources will increase. Hydrogen production methods will become mostly intermittent with renewable energies. However, due to historical hydrogen production by steam methane reforming, liquefaction was developed at steady nominal charge. In order to feed current liquefaction processes with renewable hydrogen, a buffer system will become required. This thesis studies the effect of buffer and liquefaction combination on performances and cost. In order to carry out this liquefaction from intermittent source, the study is performed based on industrial data from a variable co-product hydrogen profile. This profile acts as a simplified case. The scope of the study is drawn by considering compressed hydrogen as temporary storage for the buffer while liquefaction unit is modelled around Linde Leuna cycle. The technical-economical study covers sensitivity analysis on both buffer and liquefaction unit. For the buffer unit, storage capacity, storage pressure, liquefaction flexibility and recuperation rate impacts are examined. Liquefaction sensitivity analysis includes pressure drop, electricity cost and capacity study.  It is highlighted that 100% gaseous hydrogen recovery is not profitable due to high costs increase for recuperation higher than 95%. Storage pressure and capacity as well as liquefaction flexibility drive buffer cost and recuperation rate of the co-product hydrogen. Considering liquefaction study, results highlight that pressure drops cause first order deviations in energy consumption as well as on cost. Results show that the specific buffer cost is evaluated between 71% and 59% of liquefaction cost. Hence the thesis raises attention on future work on heat exchangers design, pressure drop optimization and liquefaction unit flexibility to allow an optimized renewable liquid hydrogen production.