Institute for Integrated Energy Systems (IESVic)

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The Institute for Integrated Energy Systems at the University of Victoria (IESVic) promotes feasible paths to sustainable energy systems by developing new technologies and perspectives to overcome barriers to the widespread adoption of sustainable energy. Founded in 1989, IESVic conducts original research to develop key technologies for sustainable energy systems and actively promotes the development of sensible, clean energy alternatives.

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IESVic's mission is to chart feasible paths to sustainable energy.

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Active magnetic regenerator experimental optimization
(2009-11-30T16:59:27Z) Tura, Armando; Rowe, Andrew Michael
A technology that has the potential to create more efficient and compact refrigeration devices is an Active Magnetic Regenerative Refrigerator (AMRR). An AMRR can operate over a broad range of temperatures, as long as the appropriate refrigerant is implemented. Thus this flexible technology can be used for small, efficient, and simple room temperature refrigerators, as well as efficient gas liquefaction plants (AMRLs). Active Magnetic Regenerator Refrigeration exploits the magnetocaloric effect displayed by magnetic materials whereby a reversible temperature change is induced when the material is exposed to a magnetic field. By using the magnetic materials in a regenerator as the heat storage medium and as the means of work input, one creates an Active Magnetic Regenerator (AMR). In this work, an experimental study of Active Magnetic Regenerators composed of single and multi-materials is carried out. AMRs made up of Gd, Gd.74Tb.26, and Gd.85Er.15 are studied in cycles rejecting heat between 270 K and 311 K. A variety of operating conditions were tested and regenerator performance with respect to heat load, utilization, and frequency was examined. AMR behavior was qualitatively interpreted and a path for performance improvement and future investigations laid.
Case study of wave power integration into the Ucluelet area electrical grid
(2009-12-07T23:36:17Z) St. Germain, Louise Anne; Rowe, Andrew Michael; Wild, Peter Martin
Technologies exist that can capture and convert wave energy but there are few studies examining systemic integration of wave energy devices. This work examines the potential to use wave energy as a renewable energy resource on Vancouver Island, specifically in the Tofino/Ucluelet area. A model of a wave energy conversion (WEC) device was developed as a module within TRNSYS™ where it can be coupled to a load as well as to a storage medium. For this particular study, wave profiles generated from hourly average data for a location on the west coast of Vancouver Island are used as a resource input. An analysis of the potential to use wave energy is carried out with an emphasis on overall system efficiency and resulting device scaling. The results of the wave energy conversion with and without storage, as well as the general economics of these scenarios, are used to make recommendations regarding technical feasibility of wave power projects on Vancouver Island.
A Comparison of methods for sizing energy storage devices in renewable energy systems
(2013-01-15) Bailey, Thomas; Rowe, Andrew Michael; Wild, Peter Martin
Penetration of renewable energy generators into energy systems is increasing. The intermittency and variability of these generators makes supplying energy reliably and cost effectively difficult. As a result, storage technologies are proposed as a means to increase the penetration of renewable energy, to minimize the amount of curtailed renewable energy, and to limit the amount of back-up supply. Therefore, methods for determining an energy system’s storage requirements are being developed. This thesis investigates and details four existing methods, proposes and develops a fifth method, and compares the results of all five methods. The results show that methods which incorporate cost, namely the Dynamic Optimization and the Abbey method, consistently yield the most cost effective solutions. Under excellent renewable energy conditions the results show that the cost-independent methods of Korpaas, Barton, and the Modified Barton method produce solutions that are nearly as cost effective but have greater reliability of energy supply than the Dynamic Optimization and Abbey solutions. This thesis recommends a new path of research for the Modified Barton method: the incorporation of cost through the confidence level. This thesis also recommends the development of new sizing methods from various aspects of the methods presented.
Dead Volume Effects in Passive Regeneration: Experimental and Numerical Characterization
(2015-09-17) Liu, Yifeng; Rowe, Andrew Michael
The regenerator is the key component in magnetic cycles for refrigeration and heat pumping. It works as temporal thermal energy storage and separates two thermal reservoirs. Regenerators are typically made up of porous structures which may create complex flow pathways for the heat transfer fluid through the regenerator. The periodically reversing flow allows the thermal energy exchange with the packing material in the regenerators. The performance of such thermal devices depends greatly on the geometry of the porous structure, material properties as well as operating conditions. This thesis is a study about the thermo-hydraulic properties of passive regenerators under oscillating flow conditions. The first part of the thesis presents a passive regenerator testing apparatus used to measure temperature distribution and pressure drop for various types of regenerators. Three kinds of loose spheres packed regenerator beds are characterized, and the regenerator effectiveness is evaluated. In the second part of the thesis, a numerical model is developed for the predictions of pressure drop and temperature field, and the theoretical findings are applied to experimentally obtained data to interpret regenerator performance. The dead volume is investigated quantitatively and considered to affect the regenerator performance adversely.
Design and Analysis of a Nested Halbach Permanent Magnet Magnetic Refrigerator
(2013-08-19) Tura, Armando; Rowe, Andrew Michael
A technology with the potential to create efficient and compact refrigeration devices is an active magnetic regenerative refrigerator (AMRR). AMRRs exploit the magnetocaloric effect displayed by magnetic materials whereby a reversible temperature change is induced when the material is exposed to a change in applied magnetic field. By using the magnetic materials in a regenerator as the heat storage medium and as the means of work input, one creates an active magnetic regenerator (AMR). Although several laboratory devices have been developed, no design has yet demonstrated the performance, reliability, and cost needed to compete with traditional vapor compression refrigerators. There are many reasons for this and questions remain as to the actual potential of the technology. The objective of the work described in this thesis is to quantify the actual and potential performance of a permanent magnet AMR system. A specific device configuration known as a dual-nested-Halbach system is studied in detail. A laboratory scale device is created and characterized over a wide range of operating parameters. A numerical model of the device is created and validated against experimental data. The resulting model is used to create a cost-minimization tool to analyze the conditions needed to achieve specified cost and efficiency targets. Experimental results include cooling power, temperature span, pumping power and work input. Although the magnetocaloric effect of gadolinium is small, temperature spans up to 30 K are obtained. Analysis of power input shows that the inherent magnetic work is a small fraction of the total work input confirming the assumption that potential cycle efficiencies can be large. Optimization of the device generates a number of areas for improvement and specific results depend upon targeted temperature spans and cooling powers. A competitive cost of cooling from a dual-nested-Halbach configuration is challenging and will depend on the ability to create regenerator matrices with near-ideal adiabatic temperature change scaling as a function of temperature.
Design Principles and Performance Metrics for Magnetic Refrigerators Operating Near Room Temperature
(2014-02-19) Arnold, Daniel Sean Robert; Rowe, Andrew Michael
In the past decade, active magnetic regenerative (AMR) refrigeration technology has progressed towards commercial application. The number of prototype systems and test apparatuses has steadily increased thanks to the worldwide research efforts. Due to the extensive variety of possible implementations of AMR, design methods are not well established. This thesis proposes a framework for approaching AMR device design. The University of Victoria now has three functional AMR Refrigerators. The newest system constructed in 2012 operates near-room-temperature and is intended primarily as a modular test apparatus with a broad range of control parameters and operating conditions. The design objectives, considerations and analysis are presented. Extensive data has been collected using the machines at the University of Victoria. Performance metrics are used to compare the devices. A semi-analytical relationship is developed that can be used as an effective modelling tool during the design process.
The effects of CO2 abatement policies on power system expansion
(2011-08-31) Fox, Conrad; Rowe, Andrew Michael; Wild, Peter Martin
Human development owes a great debt to cheap plentiful energy. Historically, abundant and energy dense materials such as coal, oil and more recently natural gas, have played an important role in powering our economies. To this day, any study analysing the short-term costs and benefits of energy system expansion, will continue to favour fossil fuels. At the same time, there is increasing concern about the levels of human made greenhouse gasses such as CO2 (the major by product of burning fossil fuels) and their forecasted effects on the global climate. This thesis investigates the consequences of using political intervention to internalize the cost of future negative effects of anthropogenic CO2 emissions. More specifically, this thesis investigates the effects of regulatory and market based instruments for curbing CO2 emissions from electric power systems in terms of both cost and efficacy. A model is developed to approximate the yearly changes in generation capacity and electricity supply mixture of a power system subject to the constraints of carbon abatement policies. The model proposes a novel approach for incorporating investment in non-dispatchable, intermittent wind generation capacity as a decision variable in the planning process. The model also investigates the effects of the stochastic nature of input parameters through the use of Monte Carlo simulation. To explore many features of this model, the Ontario power system is chosen for a case study because of its diverse portfolio of both generation technologies and political objectives. Five policies are simulated and compared with a ‘business-as-usual’ base case in which no carbon abatement policy is imposed. No single policy can meet all of the political objectives being investigated; however, some policies are clear winners in terms of specific objectives. Due to the broad scope of this work, the study finds many conclusions, such as: - Aggressive policies do not always promote heavy investment in intermittent wind generation sources. - On a $/tCO2 avoided basis, aggressive policies are expensive. Modest policies (very small penalties for CO2 emissions) are very sensitive to the uncertainties in future fuel prices and load profiles. - Investment in nuclear capacity is very responsive to the severity of CO2 penalty. The study also concludes that the most aggressive policies produce the greatest overall reductions in CO2 emissions.
Energy input, carbon intensity, and cost for ethanol produced from brown seaweed
(2013-01-15) Philippsen, Aaron; Wild, Peter Martin; Rowe, Andrew Michael
Brown macroalgae or brown seaweed is a promising source of ethanol that may avoid the challenges of arable land use, water use, lignin content, and the food vs. fuel debate associated with first generation and cellulosic ethanol sources; however, this promise is challenged by seaweed’s high water content, high ash content, and natural composition fluctuations. Notably, lifecycle studies of seaweed ethanol are lacking in the literature. To address this gap, a well-to-wheel model of ethanol production from farmed brown seaweed was constructed and applied to the case of Saccharina latissima farming in British Columbia (BC), Canada, to determine energy return on energy invested (EROI), carbon intensity (CI), and near shore seaweed farming production potential for seaweed ethanol and to examine the production cost of seaweed ethanol. Seaweed farming and ethanol production were modeled based on current BC farming methods and the dry grind corn ethanol production process; animal feed was included as an ethanol co-product, and co-product credits were considered. A seaweed ethanol yield calculation tool that accounts for seaweed composition was proposed, and a sensitivity study was done to examine case study data assumptions. In the case study, seaweed ethanol had lower CI than sugarcane, wheat, and corn ethanol at 10.1 gCO2e/MJ, and it had an EROI comparable to corn ethanol at 1.78. Seaweed ethanol was potentially profitable due to significant revenue from animal feed sales; however, the market for seaweed animal feed was limited by the feed’s high sodium content. Near shore seaweed farming could meet the current demand for ethanol in BC, but world near shore ethanol potential is likely an order of magnitude lower than world ethanol production and two orders of magnitude lower than world gasoline production. Composition variation and a limited harvest season make solar thermal or geothermal seaweed drying and storage necessary for ethanol production in BC. Varying seaweed composition, solar thermal drying performance, co-product credits, the type of animal feed produced, transport distances, and seaweed farming performance in the sensitivity study gave an EROI of over 200 and a CI of -42 gCO2e/MJ in the best case and an EROI of 0.64 and CI of 33 gCO2e/MJ in the worst case. Co-product credits and the type of animal feed produced had the most significant effect overall, and the worst cases of seaweed composition and solar thermal seaweed drying system performance resulted in EROI of 0.64 and 1.0 respectively. Brown seaweed is concluded to be a potentially profitable source of ethanol with climate benefits that surpass current ethanol sources; however, additional research into seaweed animal feed value, co-product credits, large scale seaweed conversion, and the feasibility of solar thermal or geothermal seaweed drying is required to confirm this conclusion.
Experimental and numerical determination of thermohydraulic properties of regenerators subjected to oscillating flow
(2011-08-26) Schopfer, Sandro; Rowe, Andrew Michael
Regenerators are key components in many thermal devices such as Stirling cryocoolers, magnetic refrigeration devices etc. They act as temporal thermal energy storage and therewith separate two thermal reservoirs. Regenerators are typically made up of porous structures referred to as the packing material that can lead to complex flow pathways of the heat transfer fluid through the regenerator. The nonisothermal and periodically reversing flow type allows for thermal energy exchange with the packing material of the regenerator. The performance of such devices depends greatly on the geometry of the porous structure, itsmaterial properties, length scales involved as well as operating conditions. This thesis is a study of thermohydraulic properties of thermal regenerators under oscillating flow conditions. In the first part of this thesis, thermodynamic models are developed for the extraction of the friction factor and Nusselt number from an experiment based on a harmonic approximation technique. These models are verified using a two dimensional pore scale model that allows to calculate friction factor and Nusselt number on a theoretical basis independent from an experiment. The second part of this thesis is devoted to the application of the models presented in part one to an experiment. A test apparatus that allows to measure temperature and pressure drop for various types of regenerators is presented. The measurements for a microchannel and packed bed of spheres regenerator are characterized using spectral analysis. Friction factor and Nusselt numbers are evaluated and parametrized using the models derived in the first part of this thesis. Themethodology presented in this thesis reveals insights in the dynamic effects of oscillating flow type heat transfer. The theoretical findings are applied to experimentally obtained data for a correct interpretation of friction factor and Nusselt number.
Integration of wave and tidal power into the Haida Gwaii electrical grid
(2009-08-31T21:19:28Z) Boronowski, Susan M.; Rowe, Andrew Michael; Wild, Peter Martin
Rising energy demand, fossil fuel costs, and greenhouse gas emissions have led to a growing interest in renewable energy integration. Remote communities, often accompanied by high energy costs and abundant renewable energy resources, are ideal cases for renewable energy integration. The Queen Charlotte Islands, also known as Haida Gwaii, are a remote archipelago off the northwest coast of British Columbia, Canada that relies heavily on diesel fuel for energy generation. An investigation is done into the potential for electricity generation using both tidal stream and wave energy in Haida Gwaii. A mixed integer optimization network model is developed in a Matlab and GAMS software environment, subject to set of system constraints including minimum operational levels and transmission capacities. The unit commitment and economic dispatch decisions are dynamically solved for four periods of 336 hours, representing the four annual seasons. Optimization results are used to develop an operational strategy simulation model, indicative of realistic operator behaviour. Results from both models find that the tidal stream energy resource in Haida Gwaii has a larger potential to reduce energy costs than wave energy; however, tidal steam energy is more difficult to integrate from a system operation point of view and, in the absence of storage, would only be practical at power penetration levels less than 20%.
Investigation of calculated adiabatic temperature change of MnFeP1-xAsx alloys
(2015-04-30) Campbell, David Oliver; Rowe, Andrew Michael
Magnetic refrigeration is an alternative cooling technology to vapour compression. Due to the large operating space of magnetic refrigeration devices, modelling is critical to predict results, optimize device parameters and regenerator design, and understand the physics of the system. Modeling requires accurate material data including specific heat, magnetization and adiabatic temperature change, . For a reversible material can be attained directly from measurement or indirectly through calculation from specific heat and magnetization data. Data sets of nine MnFeP1-xAsx alloys are used to compare calculated against measured . MnFeP1-xAsx is a promising first order material because of a tunable transition temperature, low material cost and large magnetocaloric properties. Because MnFeP1-xAsx alloys exhibit thermal hysteresis there are four possible calculation protocols for adiabatic temperature change; , , and . deviates the most from measured data and therefore it is assumed that this case is not representative of the material behavior. Results show and align with measured data as well as . The three protocols that align best with measured data have two consistent errors including a colder peak and a larger . With more data sets and analysis a preferred calculation protocol may be found.
Mathematical modelling of a metal hydride hydrogen storage system
(2009-11-19T21:50:00Z) MacDonald, Brendan David; Rowe, Andrew Michael
In order for metal hydride hydrogen storage systems to compete with existing energy storage technology, such as gasoline tanks and batteries, it is important to have fast reaction rates, especially quick refill times. Improving the hydriding rate involves enhancing the heat transfer within the reaction bed. To complement experimental investigations, a two-dimensional transient model has been developed to describe the heat and mass transfer phenomena within a metal hydride bed. The metal hydride model is thermally coupled to a fuel cell through heat transfer relations and utilized to compare different heat transfer enhancements and storage tank configurations. Three cases are simulated: a base case with no heat transfer enhancements, a case with fins attached to the outside of the tank, and a case with an annular tank design. The results demonstrate that the annular metal hydride tank meets the requirements of the fuel cell while providing a robust and compact hydrogen storage system.
Simplified modeling of active magnetic regenerators
(2012-08-29) Burdyny, Thomas; Rowe, Andrew Michael
Active magnetic regenerator (AMR) refrigeration is an alternative technology to conventional vapor-compression refrigerators that has the potential to operate at higher efficiencies. Based on the magnetocaloric effect, this technology uses the magnetization and demagnetization of environmentally neutral solid refrigerants to produce a cooling effect. To become competitive however, a large amount of research into the optimal device configurations, operating parameters and refrigerants is still needed. To aid in this research, a simplified model for predicting the general trends of AMR devices at a low computational cost is developed. The derivation and implementation of the model for an arbitrary AMR is presented. Simulations from the model are compared to experimental results from two different devices and show good agreement across a wide range of operating parameters. The simplified model is also used to study the impacts of Curie temperature spacing, material weighting and devices on the performance of multilayered regenerators. Future applications of the simplified AMR model include costing and optimization programs where the low computational demand of the model can be fully exploited.
Simulation of energy use in residential water heating systems
(2011-08-30) Schneyer, Carolyn Dianarose; Rowe, Andrew Michael
Current federal and provincial efficiency standards for residential water heating are based solely on the tested efficiency of individual water heating devices. Additional energy expended or saved as the water cycles through the home is not taken into account. This research, co-funded by British Columbia’s Ministry of Energy, Mines and Petroleum Resources (MEMPR), is a first step toward the Province’s goal of developing a new energy efficiency standard for water heating systems in new construction. This groundbreaking new standard would employ a “systems” approach, establishing guidelines for new construction based on the total energy used for water heating within the building envelope The research team has developed a Simulink computer model which, using a one-minute time-step, simulates 24-hour cycles of water heating in a single-family home. The objectives of this thesis are to use that model to simulate a variety of water heating technology combinations, and to devise methods of utilizing the resulting data to evaluate water heating systems as a whole and to quantify each system’s relative energy impact. A metric has been developed to evaluate the efficiency of the system: the system energy factor (SEF) is the ratio of energy used directly to heat water over the amount of energy drawn from conventional fuel sources. The CO2 impact of that energy draw is also considered. Data is generated for cities in three different climates around BC: Kamloops, Victoria and Williams Lake. Electric and gas-fired tank water heaters of various sizes and efficiencies are simulated, along with less traditional energy-saving technologies such as solar-assisted pre-heat and waste water heat recovery components. A total of 7,488 six-day simulations are run, each representing a unique combination of technology, load size, location and season. The resulting data is presented from a variety of angles, including the relative impacts of water heater rating, additional technology type, location and season on the SEF of the system. The interplay between SEF and carbon dioxide production is also examined. These two factors are proposed as the basis for devising performance tiers by which to rank water heating systems. Two proposals are made regarding how these tiers might be organized based on the data presented here, though any tiers will have to be re-evaluated pending data on a wider range of technology combinations. A brief financial analysis is also offered, exploring the potential payback period for various technology combinations in each location. Given current equipment and energy costs, the financial savings garnered by the increase in energy efficiency are not, in most cases, found to be sufficient to justify the expense to the homeowner from a purely fiscal perspective. Additional changes would need to take place to ensure the financial viability of these technologies before large-scale adoption of systems-based standards could be employed.
Sizing storage and wind generation capacities in remote power systems
(2011-10-18) Gassner, Andy; Rowe, Andrew Michael; Wild, Peter Martin
Global adoption of renewable energy is increasing due to growing concern over climate change, increasing costs associated with conventional generation, and decreasing capital investment costs of renewable energy technologies. Specifically, wind power represents the most technologically mature renewable alternative and is recognized as a cost effective generation source in both large and small power systems. However, the variability due to the stochastic nature of the wind resource introduces technological limitations to the amount of wind power which can be integrated in a power system. Energy storage is seen as a solution to mitigate the variability in wind power output. Wind power and energy storage devices have the potential to contribute a substantial amount of renewable generation to meet the electricity demand in remote power systems. Remote power systems are characterized by their self reliance on electrical generation. The basic function of a remote power system is to provide the necessary power to satisfy the community’s electricity demand requirements as economically as possible with an adequate level of continuity and reliability.
The techno-economic impacts of using wind power and plug-in hybrid electric vehicles for greenhouse gas mitigation in Canada
(2010-11-30T17:18:08Z) Kerrigan, Brett William; Rowe, Andrew Michael; Wild, Peter Martin
The negative consequences of rising global energy use have led governments and businesses to pursue methods of reducing reliance on fossil fuels. Plug-In Hybrid Electric Vehicles (PHEVs) and wind power represent two practical methods for mitigating some of these negative consequences. PHEVs use large onboard batteries to displace gasoline with electricity obtained from the grid, while wind power generates clean, renewable power that has the potential to displace fossil-fuel power generation. The emissions reductions realized by these technologies will be highly dependent on the energy system into which they are integrated, and also how they are integrated. This research aims to assess to cost of reducing emissions through the integration of PHEVs and wind power in three Canadian jurisdictions, namely British Columbia, Ontario and Alberta. An Optimal Power Flow (OPF) model is used to assess the changes in generation dispatch resulting from the integration of wind power and PHEVs into the local electricity network. This network model captures the geographic distribution of load and generation in each jurisdiction, while simulating local transmission constraints. A linear optimization model is developed in the MATLAB environment and is solved using the ILOG CPLEX Optimization package. The model solves a 168-hour generation scheduling period for both summer and winter conditions. Simulation results provide the costs and emissions from power generation when various levels of PHEVs and/or wind power are added to the electricity system. The costs and emissions from PHEV purchase and gasoline displacement are then added to the OPF results and an overall GHG reduction cost is calculated. Results indicate that wind power is an expensive method of GHG abatement in British Columbia and Ontario. This is due to the limited environmental benefit of wind over the nuclear and hydro baseload mixtures. The large premium paid for displacing hydro or nuclear power with wind power does little to reduce emissions, and thus CO2e costs are high. PHEVs are a cheaper method of GHG abatement in British Columbia and Ontario, since the GHG reductions resulting from the substitution of gasoline for hydro or nuclear power are significant. In Alberta, wind power is the cheaper method of GHG abatement because wind power is closer in price to the coal and natural gas dominated Alberta mixture, while offering significant environmental benefits. PHEVs represent a more expensive method of GHG abatement in Alberta, since substituting gasoline for expensive, GHG-intense electricity in a vehicle does less to reduce overall emissions. Results also indicate that PHEV charging should take place during off-peak hours, to take advantage of surplus baseload generation. PHEV adoption helps wind power in Ontario and British Columbia, as overnight charging reduces the amount of cheap, clean baseload power displaced by wind during these hours. In Alberta, wind power helps PHEVs by cleaning up the generation mixture and providing more environmental benefit from the substitution of gasoline with electricity.
Techno-economic optimization of integrating wind power into constrained electric networks
(2010-02-23T19:52:07Z) Maddaloni, Jesse David; Rowe, Andrew Michael; Van Kooten, G. C.
Planning electricity supply is important because power demand continues to increase while there is a concomitant desire to increase reliance on renewable sources. Extant, research pays particular attention to highly variable, low-carbon energy sources such as wind and small-scale hydroelectric power. Models generally employ only a simple load leveling technique, ensuring that generation meets demand in every period. The current research considers the power transmission system as well as load leveling. A network model is developed to simulate the integration of highly variable non-dispatchable power into an electrical grid that relies on traditional generation sources, while remaining within the network's operating constraints. The model minimizes a quadratic cost function over two periods of 336 hours, with periods representing low (summer) and high (winter) demand, subject to various linear constraints. The model is numerically solved using Matlab and GAMS software environments. Results indicate that the economic benefit of introducing zero cost wind into an existing system heavily depends on the existing generation mixture, with system cost reductions favoring wind penetration into thermally dominated mixtures. Results also show that integrating wind power into a generation mixture with a large percentage of coal capacity can increase emissions for moderate wind penetrations, and that coal facilities may economically replace lower cost alternatives under certain conditions.
Using mobile distributed pyrolysis facilities to deliver a forest residue resource for bio-fuel production
(2013-12-10) Brown, Duncan; Rowe, Andrew Michael; Wild, Peter Martin
Distributed mobile conversion facilities using either fast pyrolysis or torrefaction processes can be used to convert forest residues to more energy dense substances (bio-oil, bio-slurry or torrefied wood) that can be transported as feedstock for bio-fuel facilities. All feedstock are suited for gasification, which produces syngas that can be used to synthesise petrol or diesel via Fischer-Tropsch reactions, or produce hydrogen via water gas shift reactions. Alternatively, the bio-oil product of fast pyrolysis may be upgraded to produce petrol and diesel, or can undergo steam reformation to produce hydrogen. Implementing a network of mobile facilities reduces the energy content of forest residues delivered to a bio-fuel facility as mobile facilities use a fraction of the biomass energy content to meet thermal or electrical demands. The total energy delivered by bio-oil, bio-slurry and torrefied wood is 45%, 65% and 87% of the initial forest residue energy content, respectively. However, implementing mobile facilities is economically feasible when large transport distances are required. For an annual harvest of 1.717 million m3 (equivalent to 2000 ODTPD), transport costs are reduced to less than 40% of the total levelised delivered feedstock cost when mobile facilities are implemented; transport costs account for up to 80% of feedstock costs for conventional woodchip delivery. Torrefaction provides the lowest cost pathway of delivering a forest residue resource when using mobile facilities. Cost savings occur against woodchip delivery for annual forest residue harvests above 2.25 million m3 or when transport distances greater than 250 km are required. Important parameters that influence levelised delivered costs of feedstock are transport distances (forest residue spatial density), haul cost factors, thermal and electrical demands of mobile facilities, and initial moisture content of forest residues. Relocating mobile facilities can be optimised for lowest cost delivery as transport distances of raw biomass are reduced. The overall cost of bio-fuel production is determined by the feedstock delivery pathway and also the bio-fuel production process employed. Results show that the minimum cost of petrol and diesel production is 0.86 $ litre-1 when a bio-oil feedstock is upgraded. This corresponds to a 2750 TPD upgrading facility requiring an annual harvest of 4.30 million m3. The minimum cost of hydrogen production is 2.92 $ kg-1, via the gasification of a woodchip feedstock and subsequent water gas shift reactions. This corresponds to a 1100 ODTPD facility and requires an annual harvest of 947,000 m3. The levelised cost of bio-fuel strongly depends on the size of annual harvest required for bio-fuel facilities. There are optimal harvest volumes (bio-fuel facility sizes) for each bio-fuel production route, which yield minimum bio-fuel production costs. These occur as the benefits of economies of scale for larger bio-fuel facilities compete against increasing transport costs for larger harvests. Optimal harvest volumes are larger for bio-fuel production routes that use feedstock sourced from mobile facilities, as mobile facilities reduce total transport requirements.

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