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This study presents techno-economic analyses and life cycle assessments of four hydrogen production technologies using natural gas as a feedstock. Steam methane reforming, auto-thermal reforming and two innovative technologies: syngas chemical looping (SCL) and chemical looping reforming (CLR) are evaluated and compared. Thermodynamic analysis indicates that the CLR option can achieve the highest thermal efficiency (84%, LHV), even when CO 2 capture and liquefaction units are added. The financial analysis shows that the minimum hydrogen selling price of this system is 50%–90% of the price for the other technologies and finally, a carbon price of only $5/tonne CO 2 is required to make the CLR option (with zero direct carbon emissions) more financially attractive than SMR. While the analyses show that the CLR option is capable of achieving promising results there remain challenges to scale-up and commercialization of this technology including uniform flow distribution and reactivity of oxygen carrier. [ABSTRACT FROM AUTHOR]

This paper evaluates the financial viability of renewable jet fuel production, from two oilseed crops Camelina sativa (camelina) and Brassica carinata (carinata) and used cooking oil (UCO), by the hydrodeoxygenation pathway. A Monte Carlo analysis is performed to examine the robustness of the financial performance by taking into consideration key uncertain parameters, including capital cost, oil content of seeds, and prices of feedstocks, gas, electricity, water, meal co-product, and crude oil (indicator of fuel product prices). The Monte Carlo analysis revealed that under the conditions analyzed, the probabilities that the net present value would be positive are 29% for camelina, 18% for carinata and 8% for UCO, indicating that the three projects are risky for investors. Sensitivity analysis determined that the projects’ financial performance is highly sensitive to prices of fuel products and feedstocks. The impacts of two different hypothetical biofuel economic incentives were assessed: Carbon trading and tradable credits similar to the Renewable Identification Number (RIN). Income earned in the form of a RIN would have a large positive impact on the projects’ viabilities. By assuming an incentive of $0.20/L of renewable fuel, the probabilities that the NPV would be positive are 85% for camelina, 75% for carinata and 58% for UCO. [ABSTRACT FROM AUTHOR]

The focus of this work is to model the hydrodeoxygenation process to produce renewable jet fuel and co-products from low-input oilseeds, specifically camelina, carinata (non-edible oil) and used cooking oil (UCO), taking into account the fatty acid compositions by incorporating the stoichiometric hydrodeoxygenation reactions. This methodology provides insight into the effect of feedstock composition and hydrodeoxygenation reactions upon product yields, product distribution, hydrogen consumption and process utilities. The resulting product slates, hydrogen gas and utility demands are specific to each of the camelina, carinata and UCO feedstocks. The yield of kerosene-range alkanes ranged from 53 to 54% of the incoming oil, with 13–14% diesel range alkanes, 13–15% naphtha, and 7–9% liquefied petroleum gas, depending upon the fatty acid composition. The hydrogen consumption rate ranged from 26 to 30 kg per tonne of incoming oil, depending upon the degree of bond unsaturation. Thermal energy demand is 2.8 GJ/tonne oil when processing used cooking oil, versus 5.2 and 5.7 GJ/tonne of oil for carinata and camelina, respectively, owing to the additional energy required for oil extraction. Electricity demand was 73 kWh/tonne oil for UCO, versus 170 and 227 kWh/tonne oil for carinata and camelina. [ABSTRACT FROM AUTHOR]

The literature analyzes changes in vehicle attributes that can improve fuel economy to meet Corporate Average Fuel Economy (CAFE) standards. However, these analyses exclude either vehicle price, size, acceleration or technology advancement. A more comprehensive examination of the trade-offs among these attributes is needed, this case study focuses on technically feasible modifications to a reference 2012 vehicle to meet the 2025 fuel economy target. Scenarios developed to examine uncertainty in technology advancement indicate that expected technology cost reductions over time will be insufficient to offset the costs of additional fuel efficiency technologies that could be used to meet the 2025 fuel economy target while maintaining other vehicle attributes. The mid-price scenario results show the targeted 66% increase in fuel economy from 2012 to 2025 can be achieved with (i) a 10% ($2070) vehicle price increase (lightweight hybrid electric vehicle), (ii) a 31% (2.9 second) increase in the 0–97 km/h (60 mph) acceleration time (smaller engine), or (iii) a 17% (700 L) decrease in interior volume (smaller body) while maintaining other vehicle attributes. These results are consistent with those obtained using methods that generalize the US light-duty vehicle fleet, but are not a forecast of future vehicle attributes because combinations of less perceptible changes to vehicle price, acceleration and size would also be feasible. This study shows there are numerous ways that 2025 fuel economy targets can be met; therefore, the trade-offs quantified provide important insights on the implications of future CAFE standards. [ABSTRACT FROM AUTHOR]

This study evaluated the viability of n-butanol production integrated within a first and second generation sugarcane biorefinery. The evaluation included a deterministic analysis as well as a stochastic approach, the latter using Monte Carlo simulation. Results were promising for n-butanol production in terms of revenues per tonne of processed sugarcane, but discouraging with respect to internal rate of return (IRR). The uncertainty analysis determined there was high risk involved in producing n-butanol and co-products from ethanol catalysis. It is unlikely that these products and associated production route will be financially attractive in the short term without lower investment costs, supportive public policies and tax incentives coupled with biofuels’ production strategies. [ABSTRACT FROM AUTHOR]

Up to 500 litres of water may be consumed at the batching plant per cubic meter of ready mix concrete, if water for washing mixing trucks and equipment is included. Demand for concrete is growing almost everywhere, regardless of local availability of freshwater. The use of freshwater for concrete production exacerbates stress on natural water resources. In water-stressed coastal countries such as Israel, desalinated seawater (DSW) is often used in the production of concrete. However, the environmental impacts of this practice have not yet been assessed. In this study the effect of using DSW on the water and carbon footprints of concrete was investigated using life cycle assessment. Water footprint results highlight the benefits of using DSW rather than freshwater to produce concrete in Israel. In contrast, because desalination is an energy intensive process, using DSW increases the greenhouse gas intensity of concrete. Nevertheless, this increase (0.27 kg CO2e/m³ concrete) is small, if compared to the life cycle greenhouse gas emissions of concrete. Our results show that using untreated seawater in the mix (transported by truck from the coast) in place of DSW, would be beneficial in terms of water and carbon footprints if the batching plant were located less than 13 km from the withdrawal point. However, use of untreated seawater increases steel reinforcement corrosion, resulting in loss of structural integrity of the reinforced concrete composite. Sustainability of replacing steel with non-corrosive materials should be explored as a way to reduce both water and carbon footprints of concrete. [ABSTRACT FROM AUTHOR]

Despite international efforts to increase the adoption of alternative fuel vehicles, global gasoline internal combustion engine vehicles (ICEV-Gs) sales are projected to remain strong for the coming decades, with electric vehicles (EV) sales remaining well below 50% under International Energy Agency projections for 2030. The current study analyzes the cumulative reduction of greenhouse gas emissions that can be obtained by 2050 from policies targeting these gasoline powered vehicles. The analysis is applied to the case of the U.S. light-duty vehicles (LDV) fleet, a representative country with a large LDV fleet and slow EV penetration; the work considers technological, decisional and behavioral solutions. Technological pathways include fuel economy improvements, vehicle lightweighting and a greater provision of ethanol blends. Decisional pathways include purchasing decisions related to vehicle size and relative (best-in-class) fuel economy among available models. Behavioral pathways include improvements in driving habits. This study demonstrates the transitional and complementary role to fleet electrification that ICEV-Gs can play to meet climate targets, starting from vehicle models in the market today. A scenario-based analysis confirms that effective and diverse mitigation pathways targeting ICEV-G decarbonisation may lessen the need for aggressive fleet electrification rates – reducing the required cumulative electric vehicle sales through 2050 by at least 10% and by as much as 98% under extreme scenarios in the U.S. The analysis also identifies the limit of the ICEV-G fleet decarbonisation at 40% of cumulative lifecycle emissions from 2021 to 2050 in a very optimistic scenario, suggesting that these measures can complement but not replace the need to develop alternative fuels and powertrains. • Examined GHG mitigation measures targeting gasoline vehicle (ICEV-G) technology • Higher efficiency, hybridization & downsizing help ICEV-Gs meet GHG targets • Such measures can reduce cumulative fleet GHG emissions through 2050 by 5 to 30% • Plausible ICEV-G measures can delay need for full electrification by 5–25 years • Effective policy requires both technological improvements and behavioral changes [ABSTRACT FROM AUTHOR]

Abstract: We evaluate the implications of a range of driving patterns on the tank-to-wheel energy use of plug-in hybrid electric vehicles. The driving patterns, which reflect short distance, low speed, and congested city driving to long distance, high speed, and uncongested highway driving, are estimated using an approach that involves linked traffic assignment and vehicle motion models. We find substantial variation in tank-to-wheel energy use of plug-in hybrid electric vehicles across driving patterns. Tank-to-wheel petroleum energy use on a per kilometer basis is lowest for the city and highest for the highway driving, with the opposite holding for a conventional internal combustion engine vehicle. [Copyright &y& Elsevier]

We examined life cycle environmental and economic implications of two near-term scenarios for converting cellulosic biomass to energy, generating electricity from cofiring biomass in existing coal power plants, and producing ethanol from biomass in stand-alone facilities in Ontario, Canada. The study inventories near-term biomass supply in the province, quantifies environmental metrics associated with the use of agricultural residues for producing electricity and ethanol, determines the incremental costs of switching from fossil fuels to biomass, and compares the cost-effectiveness of greenhouse gas (GHG) and air pollutant emissions abatement achieved through the use of the bioenergy. Implementing a biomass cofiring rate of 10% in existing coal-fired power plants would reduce annual GHG emissions by 2.3 million metric tons (t) of CO2 equivalent (7% of the province's coal power plant emissions). The substitution of gasoline with ethanol/ gasoline blends would reduce annual provincial light-duty vehicle fleet emissions between 1.3 and 2.5 million t of CO2 equivalent (3.5-7% of fleet emissions). If biomass sources other than agricultural residues were used, additional emissions reductions could be realized. At current crude oil prices ($70/barrel) and levels of technology development of the bioenergy alternatives, the biomass electricity cofiring scenario analyzed is more cost-effective for mitigating GHG emissions ($22/t of CO2 equivalent for a 10% cofiring rate) than the stand-alone ethanol production scenario ($92/t of CO2 equivalent). The economics of biomass cofiring benefits from existing capital, whereas the cellulosic ethanol scenario does not. Notwithstanding this result, there are several factors that increase the attractiveness of ethanol. These include uncertainty in crude oil prices, potential for marked improvements in cellulosic ethanol technology and economics, the province's commitment to 5% ethanol content in gasoline, the possibility of ethanol production benefiting from existing capital, and there being few alternatives for moderate-to-large-scale GHG emissions reductions in the transportation sector. [ABSTRACT FROM AUTHOR]

Municipal wastewater treatment may lead to the emission of greenhouse gases. The current Intergovernmental Panel on Climate Change (Geneva, Switzerland) approach attributes only methane emissions to wastewater treatment, but this approach may overestimate greenhouse gas emissions from the highly aerobic processes primarily used in North America. To better estimate greenhouse gas emissions, a procedure is developed that can be used either with plant-specific data or more general regional data. The procedure was evaluated using full-scale data from 16 Canadian wastewater treatment facilities and then applied to all 10 Canadian provinces. The principal greenhouse gas emitted from municipal wastewater treatment plants was estimated to be carbon dioxide (CO2), with very little methane expected. The emission rates ranged from 0.005 kg CO2-equivalent/m³ treated for primary treatment facilities to 0.26 kg CO2-equivalent/m³ for conventional activated sludge, with anaerobic sludge digestion to over 0.8 kg CO2-equivalent/m³ for extended aeration with aerobic digestion. Increasing the effectiveness of biogas generation and use will decrease the greenhouse gas emissions that may be assigned to the wastewater treatment plant. [ABSTRACT FROM AUTHOR]

Alternative hydrogen production technologies are sought in part to reduce the greenhouse gas (GHG) emissions intensity compared with Steam Methane Reforming (SMR), currently the most commonly employed hydrogen production technology globally. This study investigates hydrogen production via High Temperature Steam Electrolysis (HTSE) in terms of GHG emissions and cost of hydrogen production using a combination of Aspen HYSYS® modelling and life cycle assessment. Results show that HTSE yields life cycle GHG emissions from 3 to 20 kg CO 2e /kg H 2 and costs from $2.5 to 5/kg H 2 , depending on the system parameters (e.g., energy source). A carbon price of $360/tonne CO 2e is estimated to be required to make HTSE economically competitive with SMR. This is estimated to potentially decrease to $50/tonne CO 2e with future technology advancements (e.g., fuel cell lifetime). The study offers insights for technology developers seeking to improve HTSE, and policy makers for decisions such as considering support for development of hydrogen production technologies. • Highlighting economic and environmental trade-offs of high temperature electrolysis. • Aspen HYSYS® modelling and life cycle assessment of high temperature electrolysis. • Emissions of 3–20 kgCO 2 e/kgH 2 and cost of $2.5–5/kgH2 are possible. • Carbon price of $50-$360 might been needed to make the process competitive with SMR. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) analysts are increasingly being asked to conduct life cycle‐based systems level analysis at the earliest stages of technology development. While early assessments provide the greatest opportunity to influence design and ultimately environmental performance, it is the stage with the least available data, greatest uncertainty, and a paucity of analytic tools for addressing these challenges. While the fundamental approach to conducting an LCA of emerging technologies is akin to that of LCA of existing technologies, emerging technologies pose additional challenges. In this paper, we present a broad set of market and technology characteristics that typically influence an LCA of emerging technologies and identify questions that researchers must address to account for the most important aspects of the systems they are studying. The paper presents: (a) guidance to identify the specific technology characteristics and dynamic market context that are most relevant and unique to a particular study, (b) an overview of the challenges faced by early stage assessments that are unique because of these conditions, (c) questions that researchers should ask themselves for such a study to be conducted, and (d) illustrative examples from the transportation sector to demonstrate the factors to consider when conducting LCAs of emerging technologies. The paper is intended to be used as an organizing platform to synthesize existing methods, procedures and insights and guide researchers, analysts and technology developer to better recognize key study design elements and to manage expectations of study outcomes. [ABSTRACT FROM AUTHOR]

Emerging oil sands technologies could influence industry-wide greenhouse gas emissions, however projecting future emissions is difficult due to limited public reporting of expected performance and deployment of emerging technologies. An expert elicitation was conducted to gauge how experts anticipate emerging in situ, surface mining and upgrading technologies will be deployed and perform compared to current technologies. All experts project the majority (60–98%) of in situ bitumen production in 2034 will be produced using current technologies or hybrid steam-solvent processes. Experts built boxplots to show how they project commercial projects employing emerging technologies would perform in 2034 compared to a current project employing steam-assisted gravity drainage. Across experts, the median reduction in steam-to-oil ratio for hybrid steam-solvent projects and current in situ projects employing process changes (e.g., better well placement) ranged from 3 to 30% and from 12 to 14%, respectively. Median projections from experts about the change in bitumen recovery rate compared to a current (2014) steam-assisted gravity drainage project ranged from 3 to 30% for hybrid steam-solvents and up to 15% for electro-thermal and in situ combustion projects. The responses show that a slight reduction in energy consumption from the adoption of hybrid steam-solvent processes is expected by experts. Experts projected that emerging in situ technologies, which have the largest potential for adoption, will be used primarily for accessing marginal resources and increasing overall production levels, rather than targeting greenhouse gas emissions reductions. Therefore, deployment of emerging technologies is not expected to contribute substantially to meeting greenhouse gas emissions reduction targets for the industry by 2034 under the regulatory conditions at the time of the elicitation, a key insight for policy makers. [ABSTRACT FROM AUTHOR]

Forest bioenergy can contribute to climate change mitigation by reducing greenhouse gas ( GHG) emissions associated with energy production. We assessed changes in GHG emissions resulting from displacement of coal with wood pellets for the Atikokan Generating Station located in Northwestern Ontario, Canada. Two contrasting biomass sources were considered for continuous wood pellet production: harvest residue from current harvest operations (residue scenario) and fibre from expanded harvest of standing live trees (stemwood scenario). For the stemwood scenario, two metrics were used to assess the effects of displacing coal with forest biomass on GHG emissions: (i) time to carbon sequestration parity, defined as the time from the beginning of harvest to when the combined GHG benefit of displacing coal with biomass and the amount of carbon in regenerating forest equalled the amount of forest carbon without harvest for energy production; and (ii) time to carbon debt repayment, defined as the time from the beginning of harvest to when the combined GHG benefit of displacing coal with biomass and the amount of carbon in the regenerating forest equalled forest carbon at the time of harvest. Only time to carbon sequestration parity was used for the residue scenario. In the residue scenario, carbon sequestration parity was achieved within 1 year. In the stemwood scenario, times to carbon sequestration parity and carbon debt repayment were 91 and 112 years, respectively. Sensitivity analysis showed that estimates were robust when parameter values were varied. Modelling experiments showed that increasing growth rates for regenerating stands in the stemwood scenario could substantially reduce time to carbon sequestration parity. We discuss the use of the two metrics (time to carbon sequestration parity and time to carbon debt repayment) for assessing the effects of forest bioenergy projects on GHG emissions and make recommendations on terminology and methodologies for forest bioenergy studies. [ABSTRACT FROM AUTHOR]

Carbonate reservoirs, and in particular, saline aquifers are globally abundant and promising for carbon dioxide (CO 2 ) storage. Pore network modeling of CO 2 storage in porous networks extracted from imaged carbonates provides a tool for evaluating potential storage sites. Capturing the multi-scale porosities (porosity at multiple length scales from nanometers to millimeters) inherent in carbonates is key to producing reliable pore network simulation results. Thresholding techniques that can extract the multi-scale pore space from micro computed tomography (microCT) or scanning electron microscopy (SEM) are needed. In this work, the application and evaluation of thresholding techniques originally developed for sandstones were applied and evaluated for Indiana Limestone and Pink Dolomite, carbonates that exhibit dual porosities (porosities that represent two distinct pore size distributions). The objective was to determine whether there is a single method or imaging technique that can reliably evaluate the porosity of carbonate rocks. The evaluation of the thresholding techniques applied to carbonate rocks showed that one single imaging technique or thresholding method cannot be solely used for all carbonate rocks. Instead, the evaluated porosity is a function of the microporosity, rock type and image resolution. The sensitivities of existing methods to thresholding techniques, imaging method and material structure were shown. This work provides a preliminary assessment of thresholding dual porosity carbonates. [ABSTRACT FROM AUTHOR]

This paper examines impacts of regional factors affecting biomass and process input supply chains and ongoing technology development on the life cycle greenhouse gas (GHG) emissions of ethanol production from corn stover in the U.S. Corn stover supply results in GHG emissions from −6 gCO 2 eq./MJ ethanol (Macon County, Missouri) to 13 gCO 2 eq./MJ ethanol (Hardin County, Iowa), reflecting location-specific soil carbon and N 2 O emissions responses to stover removal. Biorefinery emissions based on the 2011 National Renewable Energy Laboratory (NREL) process model are the single greatest emissions source (18 gCO 2 eq./MJ ethanol) and are approximately double those assessed for the 2002 NREL design model, due primarily to the inclusion of GHG-intensive inputs (caustic, ammonia, glucose). Energy demands of on-site enzyme production included in the 2011 design contribute to reducing the electricity co-product and associated emissions credit, which is also dependent on the GHG-intensity of regional electricity supply. Life cycle emissions vary between 1.5 and 22 gCO 2 eq./MJ ethanol (2011 design) depending on production location (98%–77% reduction vs. gasoline). Using system expansion for co-product allocation, ethanol production in studied locations meet the Energy Independence and Security Act emissions requirements for cellulosic biofuels; however, regional factors and on-going technology developments significantly influence these results. [ABSTRACT FROM AUTHOR]

Automated vehicles can facilitate vehicle sharing within and between households, thus decreasing ownership rates, albeit increasing miles travelled. While electrification can achieve deep reductions in transportation-related greenhouse gas emissions, shared automated electric vehicles will have different charging needs considering their higher mileage. In this study, travel survey data collected in Toronto is used to optimize the charging needs of shared automated electric vehicles, with the objective of reducing greenhouse gas emissions from electricity generation by choosing charging times that are associated with lower marginal emission factors. Optimized charging schedules reduce greenhouse gas emissions by at least 50% relative to vehicles charging once they return home. Life cycle assessment of multiple sharing scenarios indicates that higher levels of sharing increase emissions. Indeed, empty mileage associated with vehicle relocation and higher deterioration lead to a higher fleet turnover. With vehicle sharing, there is a risk of increasing mileage and vehicle production emissions. [ABSTRACT FROM AUTHOR]

Life cycle environmental performance of lignocellulosic ethanol produced through different production pathways and having different co-products has rarely been reported in the literature, with most studies focusing on a single pre-treatment and single co-product (electricity). The aim of this paper is to understand the life cycle energy use and greenhouse gas (GHG) emissions implications of alternative pre-treatment technologies (dilute acid hydrolysis, ammonia fiber expansion and autohydrolysis) and co-products (electricity, pellet, protein and xylitol) through developing a consistent life cycle framework for ethanol production from corn stover. Results show that the choices of pre-treatment technology and co-product(s) can impact ethanol yield, life cycle energy use and GHG emissions. Dilute acid pathways generally exhibit higher ethanol yields (20-25%) and lower net total energy use (15-25%) than the autohydrolysis and ammonia fiber expansion pathways. Similar GHG emissions are found for the pre-treatment technologies when producing the same co-product. Xylitol co-production diverts xylose from ethanol production and results in the lowest ethanol yield (200 L per dry t of stover). Compared to producing only electricity as a co-product, the co-production of pellets and xylitol decreases life cycle GHG emissions associated with the ethanol, while protein production increases emissions. The life cycle GHG emissions of blended ethanol fuel (85% denatured ethanol by volume) range from -38.5-37.2 g CO2 eq/MJ of fuel produced, reducing emissions by 61-141% relative to gasoline. All ethanol pathways result in major reductions of fossil energy use relative to gasoline, at least by 47%. [ABSTRACT FROM AUTHOR]

Replacement of fossil fuels with sustainably produced biomass crops for energy purposes has the potential to make progress in addressing climate change concerns, nonrenewable resource use, and energy security. The perennial grass Miscanthus is a dedicated energy crop candidate being field tested in Ontario, Canada, and elsewhere. Miscanthus could potentially be grown in areas of the province that differ substantially in terms of agricultural land class, environmental factors and current land use. These differences could significantly affect Miscanthus yields, input requirements, production practices, and the types of crops being displaced by Miscanthus establishment. This study assesses implications on life cycle greenhouse gas ( GHG) emissions of these differences through evaluating five Miscanthus production scenarios within the Ontario context. Emissions associated with electricity generation with Miscanthus pellets in a hypothetically retrofitted coal generating station are examined. Indirect land use change impacts are not quantified but are discussed. The net life cycle emissions for Miscanthus production varied greatly among scenarios (−90-170 kg CO2eq per oven dry tonne of Miscanthus bales at the farm gate). In some cases, the carbon stock dynamics of the agricultural system offset the combined emissions of all other life cycle stages (i.e., production, harvest, transport, and processing of biomass). Yield and soil C of the displaced agricultural systems are key parameters affecting emissions. The systems with the highest potential to provide reductions in GHG emissions are those with high yields, or systems established on land with low soil carbon. All scenarios have substantially lower life cycle emissions (−20-190 g CO2eq kWh−1) compared with coal-generated electricity (1130 g CO2eq kWh−1). Policy development should consider the implication of land class, environmental factors, and current land use on Miscanthus production. [ABSTRACT FROM AUTHOR]

Life cycle assessments can help inform decision-making about greenhouse gas (GHG) emission reduction opportunities but are often not embraced by stakeholders associated with industries where study results are highly scrutinized and often contentious. This project was motivated by stakeholder interest in understanding open source life cycle models (the Oil Production Greenhouse Gas Emissions Estimator, OPGEE, and the Petroleum Refinery Life Cycle Inventory Model, PRELIM) and how accurately they can estimate emissions for existing oil sands projects and emerging technologies. We evaluate the robustness of these models and improve them using data from three existing oil sands projects (mining + upgrading, mining + dilution, and steam assisted gravity drainage, SAGD, + dilution). The models are then applied to estimate the GHG emissions reduction potential for two emerging in situ oil sands technologies. We find that, when boundaries are aligned, OPGEE can generate upstream GHG emissions estimates for the projects modeled within 1-4% of company reported GHG emissions data. Extending the boundary to include indirect (life cycle) emissions can lead to a doubling in upstream GHG emissions intensity. The two emerging technologies evaluated in the study can reduce upstream emissions by 14-19% compared to a SAGD project operating at the same reservoir, or 1.4-1.9% on a well-to-wheel basis. This work contributes a revised process of conducting LCAs that includes stakeholder input throughout and results in more robust and transparent estimates of emissions from deploying existing and emerging technologies. • New method to engage stakeholders in life cycle assessment of oil sands projects. • Open source models estimate emissions within 1–4% of reported upstream emissions. • New technologies reduce upstream emissions 14–19% relative to current technology. • Well-to-wheel emissions decrease 1.6–1.9% with adoption of new technologies. • Adopting regional factors in open source models reduces upstream emissions 14–35%. [ABSTRACT FROM AUTHOR]

The refurbished Don Valley Brick Works' Kiln Building, in Toronto, Canada, now the TD Future Cities Centre, is designed to have net zero carbon emissions. This is to be achieved through the reuse of existing materials and structures, selection of lower-carbon materials purchased from local sources, installation of renewable energy systems, natural lighting and improved thermal insulation of the building's envelope, as well as developing a carbon offset strategy. The heritage designation of the building imposed restrictions on the design of the project (e.g., preventing insulation of exterior walls). In collaboration with the owner and constructor, the project team completed a life cycle assessment (LCA) consisting of an assessment of embodied emissions of the building's restoration from cradle to grave, accompanied by a scoping estimate of greenhouse gas emissions associated with its future operational energy use. Primary construction data for the newly-added materials, transport, and construction activities were used. Life cycle inventory analysis and impact assessment were implemented in the One Click LCA software. Use phase carbon intensity was estimated using design and literature data. In addition to the 'core and shell' LCA scope typically applied to buildings, the team also tracked materials and processes that are often not included in building LCA studies such as HVAC, plumbing, and renewable energy systems. Embodied carbon for the restoration project, assuming a 60-year lifetime, is calculated as 1250 tonnes carbon dioxide equivalent (tCO 2 e). Sixty-nine percent of the carbon comes from the materials (extraction to manufacturing) used in construction, 20% is due to replacement of materials during the building's service life, and most of the remaining 11% is from on-site construction energy (5%) and waste disposal at end-of-life (4%). The main building elements contributing to the embodied carbon are the renewable energy systems (31%) and the raised concrete floor (26%). Building envelope and foundation play minor roles, as they are mostly pre-existing. The embodied carbon added to the building through the restoration project is forecast to be balanced by savings in operational energy related to heating, cooling and lighting, within 3–13 years, depending on whether natural gas or electricity use are avoided, respectively. Uncertainties in the analysis arise from partial or missing data, modeling assumptions and future scenario unknowns. The model is sensitive to the useable lifetime of the building, local or non-local sourcing of building materials, modeling of certain components used in large quantities, and changes in the recycled content of steel. This study of a net zero carbon refurbishment project of a heritage building provides insights for assessments of future projects as such refurbishments become more commonplace. The methods and recommendations regarding data sources, data collection, and approach to uncertainty evaluation will be useful for LCA of any construction project. • A brick kiln building was refurbished as an event space targeting net zero carbon. • Existing structures were upgraded and a geo-solar exchange system installed. • Total project embodied carbon is estimated at 255 kgCO 2 e/m2, given a 60-year lifetime. • 69% of estimated GHG emissions are embodied in materials purchased during construction. • Results are sensitive to building lifetime, datapoint modeling and other parameters. [ABSTRACT FROM AUTHOR]

Replacing conventional gasoline with mid-level ethanol blends (15–30% ethanol by volume) can reduce fossil fuel use and greenhouse gas (GHG) emissions but require vehicle compatibility. This study quantifies the changes in fuel volumes and well-to-wheel (WTW) GHG emissions associated with potential mid-level ethanol blend deployment in Canada's light-duty vehicle fleet from 2018 to 2030. We develop a Canadian fleet model that projects the number of vehicles by vehicle technology and production year from 2015 to 2030, their fuel blend compatibilities, and their annual fuel use, considering the potential effects of ethanol blend level on vehicle fuel consumption and associated GHG emissions. The results show that the deployment of low and mid-level ethanol blends, such as E10, E15 or E25, could reduce petroleum gasoline use by 12% in 2030, while tripling ethanol use, from 2.6 to 7.2 billion liters annually. Incorporating emission factors from the GHGenius model suggests that mid-level blends can reduce fleet WTW GHG emissions in 2030 by 7.2% assuming the use of corn and wheat ethanol, and by up to 13.4% assuming cellulosic ethanol. The octane enhancing effect of ethanol is responsible for up to 30% of the reductions. Achieving the above reductions would require coordination among vehicle manufacturers, refiners and policymakers. Overall, mid-level blends can materially reduce GHG emissions of the Canadian light-duty fleet, but represent less than 1/5 of the reductions required for the light-duty fleet to achieve emissions that are 30% below 2005 levels (Canada's pledge under the Paris Agreement). • We estimate the GHG emission implications of mid-level ethanol blends in Canada. • Conventional mid-level ethanol blends could reduce WTW GHG emissions 7.2% in 2030. • Cellulosic mid-level ethanol blends could reduce WTW GHG emissions 13.4% in 2030. • Octane enhancing effect of ethanol accounts for 30% of GHG emissions reduction. • Reductions require coordination among vehicle manufacturers, refiners and policymakers. [ABSTRACT FROM AUTHOR]

Although the life cycle greenhouse gas (GHG) emissions associated with Canadian oil sands have been investigated in recent years, questions remain regarding the source and impact of variability in emissions in this industry over time. This study combines publicly-available data from the fifteen largest operating in situ extraction projects, i.e., cyclic steam stimulation (CSS) and steam assisted gravity drainage (SAGD) with a statistically-enhanced life cycle model to investigate variability in well-to-wheel (WTW) GHG emissions. We estimate that the WTW GHG emissions from CSS-derived gasoline range from 99 to 114 g CO 2 eq/MJ (80% confidence interval), 6–22% higher than the RFS2 baseline. The corresponding range for SAGD-derived gasoline is 98–133 g CO 2 eq/MJ, 5–42% higher than the RFS2 baseline. SAGD-derived gasoline has more variability as some operators "upgrade" their crudes, emitting GHGs, whereas no CSS operator employs upgrading. Without upgrading, the 90th percentile for SAGD emissions would be 114 g CO 2 eq/MJ. Upstream variability in GHG emissions drives the positively skewed WTW GHG distributions. This demonstrates the importance of understanding the nature and magnitude of variability and uncertainty in decision making. • Source and impact of variability in oil sands LC GHG estimates are understudied. • SAGD LC GHG emissions 5–22% higher than EPA RFS2 gasoline (w/o upgrading). • CSS LC GHG emissions 6–22% higher than EPA RFS2 gasoline (w/o upgrading). • LC emissions variability driven by upstream inputs and if upgrading is used. [ABSTRACT FROM AUTHOR]

Existing life cycle assessments of concrete containing supplementary cementitious materials (SCMs) hinge on methodological procedures that might skew the results towards the conclusion that increasing the use of SCMs in concrete always decreases greenhouse gas (GHG) emissions. These procedures relate to the treatment of co-products and selection of functional units. Co-production is typically addressed via cut-off procedures and by-products are always considered to be unconstrained resources, while functional units often do not account for exposure conditions and concrete properties such as strength and workability. To address this limitation, the aim of this study was to investigate the GHG benefits of using SCMs by (1) adopting different approaches to solve multifunctionality (cut-off vs. substitution) and (2) including strength, workability and exposure conditions of concrete in the functional unit. Ontario (Canada) was used as case study, and both SCMs currently used there (i.e., slag, silica fume and metakaolin) and a wide range of alternative cementitious materials used around the world (i.e., fly ash, oil shale ash, calcium carbide residue, volcanic ash, coal bottom ash and rice husk ash) were investigated. The new contribution of this study reveals that different conclusions can be drawn when different methodological procedures are adopted. If the market for SCM is constrained (i.e., by-products are already fully utilized) and the unconstrained alternative on the market is Portland cement, the benefits of using SCM are greatly reduced, or even reversed, if the substitution approach is adopted. In contrast, unconstrained SCMs result in considerable GHG savings unless they significantly reduce the water-to-binder ratio to reach a prescribed strength and require long distance transport. • Market constraints of SCMs should be included in LCA studies of concrete. • Concrete properties and exposure conditions must be included in the functional unit. • If the SCM is constrained, overall GHG benefits of using it are greatly reduced. • Increasing SCMs in concrete does not always decrease its GHG emissions. • The use of alternative unconstrained SCMs should be further explored and promoted. [ABSTRACT FROM AUTHOR]