Publications
107 results found
Guo M, 2018, Multi-scale system modelling under circular bioeconomy, Computer Aided Chemical Engineering, Publisher: Elsevier, Pages: 833-838
Noor S, Guo M, van Dam KH, et al., 2018, Energy demand side management with supply constraints: Game theoretic approach, Applied Energy Symposium and Forum on Renewable Energy Integration with Mini/Microgrid Systems (REM), Publisher: Elsevier, Pages: 368-373, ISSN: 1876-6102
The management of energy supply and demand is becoming more challenging in regions where the demand continues to grow rapidly and more intermittent renewable supply sources are added to the energy infrastructure. In this context, Demand Side Management (DSM) can be employed to improve reliability of supply and stretch the capacity limits of the existing grid infrastructure. A game theoretic approach for DSM model incorporating storage components is suggested in this paper for environments with supply constraints. The proposed model is able to not only reduce the Peak-to-Average ratio to benefit the electric grid, but also smoothen the dips in load profile caused by supply constraints.
Liu M, van Dam KH, Pantaleo AM, et al., 2018, Optimisation of integrated bioenergy and concentrated solar power supply chains in South Africa, 28th European Symposium on Computer-Aided Process Engineering (ESCAPE), Publisher: Elsevier, Pages: 1463-1468, ISSN: 1570-7946
Climate change and energy security are complex challenges whose solutions depend on multi-faceted interactions between different actors and socio-economic contexts. Energy innovation through integration of renewable energies in existing systems offers a partial solution, with high potential identified for bioenergy and solar energy. In South Africa there is potential to further integrate renewable energies to meet local demands and conditions. Various concentrated solar power (CSP) projects are in place, but there is still land available to generate electricity from the sun. In combination with sustainable biomass resources these can offer synergetic benefits in improving the power generation’s flexibility. While thermodynamic and thermo-economic modelling for hybrid CSP-Biomass technology have been proposed, energy modelling in the realm of supply chains and demand/supply dynamics has not been studied sufficiently.We present a spatially and temporally Mixed Integer Linear Programming (MILP) model, to optimize the choice and location of technologies in terms of economic cost while being characterised by realistic supply/demand constraints as well as spatially-explicit environmental constraints. The model is driven by electricity demand, resource availability and technology costs as it aspires to emulate key energy and sustainability issues. A case study in the South African province of Gauteng was implemented over 2015-2050 to highlight the potential and challenges for hybrid CSP-Biomass and integrated systems assessment and the applicability of the modelling approach.From the range of hybrid CSP-Biomass technologies considered, based on detailed techno-economic characteristics from the literature, the Biomass only EFGT plant is identified as the cost optimal. When distributed generation (DG) technologies, small-scale Solar PV and Wind Turbines were introduced to the model as a competing alternative, they were demonstrated to be more economically optimal (&eur
Guo M, Chee G, O'Connell D, et al., 2018, Use of an Alternating Optimization Scheme with a Non-Linear Conjugate Gradient Method for Reconstructing High Quality CBCT and Motion Models from Free Breathing CBCT Projections, 60th Annual Meeting of the American-Association-of-Physicists-in-Medicine, Publisher: WILEY, Pages: E387-E387, ISSN: 0094-2405
Guo M, Chee G, O'Connell D, et al., 2018, Reconstruction of a Respiratory Motion Model and a High-Quality Reference Image From CBCT Projections Acquired in Treatment Position. A Retrospective Study Using Patient Images, 60th Annual Meeting of the American-Association-of-Physicists-in-Medicine, Publisher: WILEY, Pages: E705-E705, ISSN: 0094-2405
Wang X, Guo M, Koppelaar RHEM, et al., 2018, A nexus approach for sustainable urban energy-water-waste systems planning and operation, Environmental Science and Technology, Vol: 52, Pages: 3257-3266, ISSN: 0013-936X
Energy, water and waste systems analyzed at a nexus level is key to move towards more sustainable cities. In this paper, the “resilience.io” platform is developed and applied to emphasize on waste-to-energy pathways, along with the water and energy sectors, aiming to develop waste treatment capacity and energy recovery with the lowest economic and environmental cost. Three categories of waste including wastewater (WW), municipal solid waste (MSW) and agriculture waste are tested as the feedstock for thermochemical treatment via incineration, gasification or pyrolysis for combined heat and power generation, or biological treatment such as anaerobic digestion (AD) and aerobic treatment. A case study is presented for Ghana in Sub-Saharan Africa, considering a combination of waste treatment technologies and infrastructure, depending on local characteristics for supply and demand. The results indicate that the biogas generated from waste treatment turns out to be a promising renewable energy source in the analyzed region, while more distributed energy resources can be integrated. A series of scenarios including the business-as-usual, base case, natural constrained, policy interventions and environmental and climate change impacts demonstrate how simulation with optimization models can provide new insights in the design of sustainable value chains, with particular emphasis on whole-system analysis and integration.
O'Dwyer E, Wang H, Wang A-J, et al., 2018, Optimisation of Wastewater Treatment and Recovery Solutions in Industrial Parks, Editors: Friedl, Klemes, Radl, Varbanov, Wallek, Publisher: ELSEVIER SCIENCE BV, Pages: 1407-1412
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- Citations: 8
Wang X, Guo M, Van Dam KH, et al., 2017, Waste-Energy-Water systems in sustainable city development using the resilience.io platform, 27th European Symposium on Computer Aided Process Engineering
Crémel S, Guo M, Bustos-Turu G, et al., 2017, Optimal design of urban energy systems with demand side management and distributed generation, 27th European Symposium on Computer Aided Process Engineering, Publisher: Elsevier, Pages: 2371-2376, ISSN: 1570-7946
To tackle prominent societal challenges such as increasing energy demands and climate change due to greenhouse gas (GHGs) emissions demand side management (DSM) and distributed generation (DG) have been proposed as effective solutions particularly for urban areas with high energy densities and diverse types of energy demands. However, urban energy systems are complex, involving supply-demand interconnections, interaction of whole system level with various stakeholders (e.g. end-users, centralised suppliers) and regulation effects of policy instruments. The potential roles of integrated DSM and DG for the climate change mitigation under the urban energy system context haven been yet well understood. Our research aims to advance the understanding of such promising urban energy solutions and generate new insights via modelling framework development. In this study, an optimisation model is developed to simulate the combined effects of DSM and DG strategies in the optimal design of urban energy systems, and investigate the trade-offs between environmental and economic targets. The results of our case study on a hypothetical urban area suggest that the effects of just DSM on climate change mitigation are relatively low whereas urban system would benefit significantly from the introduction of more carbon efficient and economically competitive DG technologies. The set of Pareto optimal solutions derived from the model provide insights into the trade-offs between conflicting GHG and economic objectives: the environmentally optimal solutions with up to 39-43% of the GHG reduction are derived at the expenses of a cost increase by 73-87%; relatively cost efficient systems with marginal increase in economic profiles (4-5%) but significant GHG reductions (32-33%) are achievable. This study demonstrates the insights such model could provide for the decision-making and paradigm shifts towards sustainable urban energy systems and smart operational strategies.
Riveros M, Guo M, van dam, et al., 2017, Carbon Arbitrage with Stationary Batteries in the City of London, 27th European Symposium on Computer Aided Process Engineering, Publisher: Elsevier, Pages: 529-534, ISSN: 1570-7946
Stationary batteries could facilitate provision of carbon arbitrage services in cities. Such services offer a smart solution to integrate low-carbon energy technology into grid electricity supply and help tackle climate change. In this paper the environmental implications and overall profitability of this approach are assessed. A modelling framework has been developed to design an energy storage system with optimal capacity to maximise carbon savings. The City of London was used as a case study to demonstrate model applicability and analyse the potential effect of intermittent renewable energy sources in the supply system. The total savings obtained for the carbon arbitrage service were economically valorised using carbon market prices. In addition, a critical profitability thresholds for carbon trading prices are identified. Results show that this approach could bring environmental benefits depending on the carbon intensity of the grid, but that high carbon trading prices are required before it is economically feasible.
Puchongkawarin C, Vaupel Y, Guo M, et al., 2017, Towards the synthesis of wastewater recovery facilities using enviroeconomic optimization, The Water-Food-Energy Nexus - Processes, Technologies, and Challenges, Editors: Mujtaba, Srinivasan, Elbashir, ISBN: 9781498760843
The wastewater treatment industry is undergoing a major shift towards a proactive interest in recovering materials and energy from wastewater streams, driven by both economic incentives and environmental sustainability. With the array of available treatment technologies and recovery options growing steadily, systematic approaches to determining the inherent trade-off between multiple economic and environmental objectives become necessary, namely enviroeconomic optimization.The main objective of this chapter is to present one such methodology based on superstructure modeling and multi-objective optimization, where the main environmental impacts are quantified using life cycle assessment (LCA). This methodology is illustrated with the case study of a municipal wastewater treatment facility. The results show that accounting for LCA considerations early on in the synthesis problem may lead to dramatic changes in the optimal process configuration, therebysupporting LCA integration into decision-making tools for wastewater treatment alongside economical selection criteria.
Duan ML, Guo M, Stuckey D, 2017, Economic and Environmental Evaluation of Phosphorus Removal and Recovery Methods from Wastewate, IWA The 2nd International Resource Recovery Conference
Wang X, Guo M, van dam K, et al., 2017, Waste-Energy-Water systems in sustainable city development using the resilience.io platform, 27th European Symposium on Computer Aided Process Engineering
Farzad S, Mandegari MA, Guo M, et al., 2017, Multi‑product biorefineries from lignocelluloses: a pathway to revitalisation of the sugar industry?, Biotechnology for Biofuels, Vol: 10, ISSN: 1754-6834
BackgroundDriven by a range of sustainability challenges, e.g. climate change, resource depletion and expanding populations, a circular bioeconomy is emerging and expected to evolve progressively in the coming decades. South Africa along with other BRICS countries (Brazil, Russia, India and China) represents the emerging bioeconomy and contributes significantly to global sugar market. In our research, South Africa is used as a case study to demonstrate the sustainable design for the future biorefineries annexed to existing sugar industry. Detailed techno-economic evaluation and Life Cycle Assessment (LCA) were applied to model alternative routes for converting sugarcane residues (bagasse and trash) to selected biofuel and/or biochemicals (ethanol, ethanol and lactic acid, ethanol and furfural, butanol, methanol and Fischer–Tropsch synthesis, with co-production of surplus electricity) in an energy self-sufficient biorefinery system.ResultsEconomic assessment indicated that methanol synthesis with an internal rate of return (IRR) of 16.7% and ethanol–lactic acid co-production (20.5%) met the minimum investment criteria of 15%, while the latter had the lowest sensitivity to market price amongst all the scenarios. LCA results demonstrated that sugarcane cultivation was the most significant contributor to environmental impacts in all of the scenarios, other than the furfural production scenario in which a key step, a biphasic process with tetrahydrofuran solvent, had the most significant contribution.ConclusionOverall, the thermochemical routes presented environmental advantages over biochemical pathways on most of the impact categories, except for acidification and eutrophication. Of the investigated scenarios, furfural production delivered the inferior environmental performance, while methanol production performed best due to its low reagent consumption. The combined techno-economic and environmental assessments identified the performance-limiting steps in
Guo M, Richter GM, Holland RA, et al., 2016, Implementing land-use and ecosystem service effects into an integrated bioenergy value chain optimisation framework, Computers and Chemical Engineering, Vol: 91, Pages: 392-406, ISSN: 0098-1354
This study presents a multi-objective optimisation model that is configured to account for a range of interrelated or conflicting questions with regard to the introduction of bioenergy systems. A spatial-temporal mixed integer linear programming model ETI-BVCM (Energy Technologies Institute – Bioenergy Value Chain Model) (ETI, 2015b, Newton-Cross, 2015, Samsatli et al., 2015) was adopted and extended to incorporate resource-competing systems and effects on ecosystem services brought about by the land-use transitions in response to increasing bioenergy penetration over five decades. The extended model functionality allows exploration of the effects of constraining ecosystem services impacts on other system-wide performance measures such as cost or greenhouse gas emissions. The users can therefore constrain the overall model by metric indicators which quantify the changes of ecosystem services due to land use transitions. The model provides a decision-making tool for optimal design of bioenergy value chains supporting an economically and land-use efficient and environmentally sustainable UK energy system while still delivering multiple ecosystem services.
Patel B, Guo M, Chong C, et al., 2016, Hydrothermal upgrading of algae paste: inorganics and recycling potential in the aqueous phase, Science of the Total Environment, Vol: 568, Pages: 489-497, ISSN: 0048-9697
Hydrothermal Liquefaction (HTL) for algal biomass conversion is a promising technology capable of producing high yields of biocrude as well as partitioning even higher quantity of nutrients in the aqueous phase. To assess the feasibility of utilizing the aqueous phase, HTL of Nannochloropsis sp. was carried out in the temperature range of 275 to 350 °C and Residence Times (RT) ranging between 5 and 60 min The effect of reaction conditions on the NO3− , PO43 − , SO42 − , Cl− , Na+ , and K+ ions as well as Chemical Oxygen Demand (COD) and pH was investigated with view of recycling the aqueous phase for either cultivation or energy generation via Anaerobic Digestion (AD), quantified via Lifecycle Assessment (LCA). It addition to substantial nutrient partitioning at short RT, an increase in alkalinity to almost pH 10 and decrease in COD at longer RT was observed. The LCA investigation found reaction conditions of 275 °C/30 min and 350 °C/10 min to be most suitable for nutrient and energy recovery but both processing routes offer environmental benefit at all reaction conditions, however recycling for cultivation has marginally better environmental credentials compared to AD.
Lin YZ, Guo M, Shah N, et al., 2016, Economic and environmental evaluation of nitrogen removal and recovery methods from wastewater, Bioresource Technology, Vol: 215, Pages: 227-238, ISSN: 1873-2976
The driver for waste-based economic growth is long-term strategic design, and a paradigm-shift from waste treatment to resource recovery. This study aims to use an integrated modelling approach to evaluate the holistic economic and environmental profiles of three alternative nitrogen removal and recovery methods integrated into wastewater treatment systems, including conventional nitrification-denitrification, Anammox, and the anaerobic ion exchange route, to provide insights into N recovery system designs which are key elements in building a sustainable circular economy. Our results suggest that ion exchange is a promising technology showing high N removal-recovery efficiency from municipal wastewater and delivering competitive sustainability scores. In comparison with the well-developed conventional route, ion exchange and Anammox are undergoing significant research and development; as highlighted in sensitivity analyses, there is considerable room for process design and optimization of ion exchange systems to achieve economically and environmentally optimal performance.
Patel B, Guo M, Shah N, et al., 2016, Environmental Profile of Algal Hydrothermal Liquefaction – A Country Specific Case Study, Algal Research-Biomass Biofuels and Bioproducts, Vol: 16, Pages: 127-140, ISSN: 2211-9264
Microalgae are known to be an important feedstock not just for biofuel but also biochemical production. In this investigation we utilise a cradle-to-biorefinery-gate attributional LCA (aLCA) methodology to evaluate the environmental impacts of Nannochloropsis sp. derived algal biocrude production. A database of primary experimental data for continuous fast Hydrothermal Liquefaction (HTL) and Hydrotreating (HDT) is combined with secondary data from literature to investigate the overall environmental profiles of cultivation, dewatering, HTL and HDT for various scenarios based on the energy generation mix of 5 countries (Brazil, UK, Spain, China and Australia) as well as a comparison with fossil crude. The investigation found that Brazil delivers best environmental profiles for all scenarios, primarily due to its significant contribution from hydropower. Furthermore, the cultivation and HTL processes account for nearly 90% of environmental burdens whereas dewatering and HDT only contribute less than 8%. The research findings highlight the importance of the several factors on the resulting 3G biofuel profiling e.g. energy resource, processing technology choice and the co-product(s) and emissions profiling methodology. Algal biocrude is still undergoing research and development compared to the well-developed fossil crude industry. Via integration and optimisation at process and value chain levels, algae-derived biocrude has the potential to deliver an environmentally sustainable alternative to the fossil crude, provided the energy input for processing is from a renewable source.
Nguyen R, Guo M, Musikavong C, et al., 2016, Supply Chain Optimisation of Nipa-based bioethanol industry in Thailand, 26th European Symposium on Computer Aided Process Engineering (ESCAPE 26), ISSN: 1570-7946
Delval F, Guo M, van Dam KH, et al., 2016, Integrated multi-level bioenergy supply chain modelling applied to sugarcane biorefineries in South Africa, 26th European Symposium on Computer Aided Process Engineering, ISSN: 1570-7946
Patel B, Guo M, Izadpanah A, et al., 2016, A Review on Hydrothermal Pre-treatment Technologies and Environmental Profiles of Algal Biomass Processing, Bioresource Technology, Vol: 199, Pages: 288-299, ISSN: 1873-2976
The need for efficient and clean biomass conversion technologies has propelled Hydrothermal (HT) processing as a promising treatment option for biofuel production. This manuscript discussed its application for pre-treatment of microalgae biomass to solid (biochar), liquid (biocrude and biodiesel) and gaseous (hydrogen and methane) products via Hydrothermal Carbonisation (HTC), Hydrothermal Liquefaction (HTL) and Supercritical Water Gasification (SCWG) as well as the utility of HT water as an extraction medium and HT Hydrotreatment (HDT) of algal biocrude. In addition, the Solar Energy Retained in Fuel (SERF) using HT technologies is calculated and compared with benchmark biofuel. Lastly, the Life Cycle Assessment (LCA) discusses the limitation of the current state of art as well as introduction to new potential input categories to obtain a detailed environmental profile.
Bustos G, Guo M, van Dam KH, et al., 2016, Incorporating life cycle assessment indicators into optimal electric vehicle charging strategies: An integrated modelling approach, Editors: Kravanja, Bogataj, Publisher: ELSEVIER SCIENCE BV, Pages: 241-246
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Guo M, Li CS, Facciotto G, et al., 2015, Bioethanol from poplar clone Imola: an environmentally viable alternative to fossil fuel?, Biotechnology for Biofuels, Vol: 8, Pages: 1-21, ISSN: 1754-6834
Background: Environmental issues, e.g. climate change, fossil resource depletion have triggered ambitious national/regional policies to develop biofuel and bioenergy roles within the overall energy portfolio to achieve decarbonising the global economy and increase energy security. With the 10 % binding target for the transport sector, the Renewable Energy Directive confirms the EU’s commitment to renewable transport fuels especially advanced biofuels. Imola is an elite poplar clone crossed from Populus deltoides Bartr. and Populus nigra L. by Research Units for Intensive Wood Production, Agriculture Research Council in Italy. This study examines its suitability for plantation cultivation under short or very short rotation coppice regimes as a potential lignocellulosic feedstock for the production of ethanol as a transport biofuel. A life cycle assessment (LCA) approach was used to model the cradle-to-gate environmental profile of Imola-derived biofuel benchmarked against conventional fossil gasoline. Specific attention was given to analysing the agroecosystem fluxes of carbon and nitrogen occurring in the cultivation of the Imola biomass in the biofuel life cycle using a process-oriented biogeochemistry model (DeNitrification-DeComposition) specifically modified for application to 2G perennial bioenergy crops and carbon and nitrogen cycling.Results: Our results demonstrate that carbon and nitrogen cycling in perennial crop–soil ecosystems such as this example can be expected to have significant effects on the overall environmental profiles of 2G biofuels. In particular, soil carbon accumulation in perennial biomass plantations is likely to be a significant component in the overall greenhouse gas balance of future biofuel and other biorefinery products and warrants ongoing research and data collection for LCA models. We conclude that bioethanol produced from Imola represents a promising alternative transport fuel offering some savings ranging from 35 to 1
Guo M, Shah N, 2015, Bringing Non-energy Systems into a Bioenergy Value Chain Optimization Framework, 12th International Symposium on Process Systems Engineering and 25th European Symposium on Computer Aided Process Engineering, ISSN: 1570-7946
Zeng X, Guo M, Gao H, 2015, Rapid Direct Aperture Optimization Via Piecewise Linear Dose Calculation Based On the Dose Influence Matrix, 57th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM), Publisher: AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS, Pages: 3740-3741, ISSN: 0094-2405
Guo M, Craft D, Gao H, 2015, Plan Averaging for Multi-Criteria Navigation of Step-And-Shoot IMRT, 57th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM), Publisher: WILEY, Pages: 3477-3477, ISSN: 0094-2405
Guo M, Li R, Xing L, et al., 2015, A GPU-Based Iterative Image Reconstruction Solver with 4D Regularization for Low-Dose Helical 4DCT, 57th Annual Meeting and Exhibition of the American-Association-of-Physicists-in-Medicine (AAPM), Publisher: AMER ASSOC PHYSICISTS MEDICINE AMER INST PHYSICS, Pages: 3728-3729, ISSN: 0094-2405
Thornley P, van Zyl E, Benton T, et al., 2015, A Bioenergy Research Prospectus for Southern Africa, A Bioenergy Research Prospectus for Southern Africa
Patel B, Guo M, Shah N, et al., 2015, Environmental Profile of Algal Hydrothermal Liquefaction, 21th International Symposium on Alcohol Fuels
Guo M, Littlewood J, Joyce J, et al., 2014, The environmental profile of bioethanol produced from current and potential future Poplar feedstocks in the EU, Green Chemistry
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