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There is growing interest in the use of hydrogen as a transportation fuel but the environmental benefits of using hydrogen depend critically on how it is produced and distributed. Leading alternatives to using fossil natural gas to make hydrogen through the conventional method of steam methane reforming include using electrolyzers to split water into hydrogen and oxygen, and the use of biogas as an alternative feedstock to fossil natural gas. This report examines the latest carbon intensity (CI) estimates for these and various other hydrogen production processes, adding important nuances to the general “colors of hydrogen” scheme that has been used in recent years. CI values for hydrogen production can vary widely both within and across hydrogen production pathways. The lowest CI pathways use biomass or biogas as a feedstock, and solar or wind power. The report also analyses jobs creation from new hydrogen production facilities and shows that these benefits can be significant for large-scale facilities based on either future biomass/biogas-to-hydrogen or solar-hydrogen production technologies. Recommendations include setting stricter goals for the state’s Low Carbon Fuel Standard (LCFS) program to continue to reduce the carbon footprint of California’s transportation fuels.

We have conducted a study to review and synthesize the current state of data availability for cradle-to-grave life-cycle emissions from major building technologies and electricity generation and storage technologies as specific to California as could be found. Results from 280 building technologies (120 unique) were organized across 9 categories and 27 subcategories. Many of the technologies in the list are common building materials, appliances, and process equipment used in the construction and operation of agricultural, residential, commercial, and industrial buildings. Target electricity generation technologies covered the GHG emissions from natural gas, solar, wind, geothermal, biomass and storage technologies for the California context. The search for relevant environmental impact data was in the form of Environmental Product Declarations (EPD) (if available), peer-reviewed journal articles, and publicly available reports from government and industry for each technology. In general, the “Building Materials” category in the building technologies area and “Wind Turbines” in the electricity generation and storage area have the most current and relevant data for California. However, we have identified several data gaps in our survey of the remaining categories. Due to lack of relevant data for California in building systems, there is an urgent need for policy makers and industry stakeholders to replicate policies such as AB 2446 to expand the coverage of availability of EPDs for products. Similarly, to achieve the SB 350 (Clean Energy and Pollution Reduction Act) goals and to support the state’s efforts to reduce GHG emissions by 80% below 1990 levels by the year 2050, we need to account for embodied emissions together with the other important life-cycle stages of renewable energy sources.

California must operate and maintain an effective and efficient transportation infrastructure while ensuring that the health of communities and the planet are not compromised. By assessing transportation projects using a life-cycle perspective, all relevant emission sources and activities from the construction, operation, maintenance, and end-of-life phases can be analyzed and mitigated. This report presents a framework to assess the life-cycle human health and climate change impacts from six types of transportation projects: (1) Roadways; (2) Marine ports; (3) Logistical distribution centers; (4) Railyards; (5) Bridges and overpasses; and (6) Airports. The framework was applied using an integrated model to assess fine particulate matter (PM2.5) and greenhouse gas (GHG) emissions, noise impacts, and monetized damages (Value of Statistical Life, Social Cost of Carbon) from two case studies: routine resurfacing and vehicle operations on road segments within the San Francisco Bay Area using 2019 data, and annual marine, cargo, rail, trucking, and infrastructure maintenance operations at the Port of Oakland in 2020. The results suggest that emission sources in a project’s supply chain and construction (material production and deliveries, construction activities, fuel refining) can significantly contribute to the full scope of impacts from transportation systems. Equitable mitigation policies (e.g., electrification, pollution control technologies) need to be tailored to address the sources that impact communities the most.

While recognized as important, calculation of embodied energy and greenhouse gas (GHG) emissions associated with buildings, especially at a large scale, has scant literature. A model has been created for estimating the inventory of structural and non-structural materials and building components and their associated embodied energy and GHG emissions for the approximately 807,400 office buildings constructed in the United States between 1946 and 2018. The buildings were modeled using eight prototypical designs. We estimate that 1100–1300 million metric tons of materials are embodied in these 807,000 buildings (90% of which have just 1–3 floors), as well as 6–7 years' worth of national construction and demolition waste. In total, 6.5 billion Gigajoules of primary energy use (∼6% of the U.S.’s 2021 energy consumption) and 0.5 billion metric tons of carbon dioxide equivalent emissions (∼8% of the U.S.’s 2020 total GHG emissions) are estimated to be embodied in these buildings. One-floor steel and wood buildings were about equally GHG intensive from structural materials as well as combined structural and non-structural materials perspectives, while reinforced concrete (RC) buildings were 50% and 27%–47% more GHG intensive, respectively. From the all-materials-use perspective, 5-floor steel buildings were 54% more GHG intensive to construct than wood buildings, and in turn RC buildings were 68% more GHG intensive than steel buildings. Non-structural material contributions were significant. Increasing economies of scale in embodied impacts can be observed as the number of floors increases. Results constitute points of reference for those who seek to find ways of reducing the carbon footprint of buildings.

Increasingly stringent limits on nutrient discharges are motivating water resource recovery facilities (WRRFs) to consider the implementation of sidestream nutrient removal or recovery technologies. To further increase biogas production and reduce landfilled waste, WRRFs with excess anaerobic digestion capacity can accept other high-strength organic waste (HSOW) streams. The goal of this study was to characterize and evaluate the life-cycle global warming potential (GWP), eutrophication potential, and economic costs and benefits of sidestream nutrient management and biosolid management strategies following digestion of sewage sludge augmented by HSOW. Five sidestream nutrient management strategies were analyzed using environmental life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) for codigestion of municipal sewage sludge with and without HSOW. As expected, thermal stripping and ammonia stripping were characterized by a much lower eutrophication potential than no sidestream treatment; significantly higher fertilizer prices would be needed for this revenue stream to cover the capital and chemical costs. Composting all biosolids dramatically reduced the GWP relative to the baseline biosolid option but had slightly higher eutrophication potential. These complex environmental and economic tradeoffs require utilities to consider their social, environmental, and economic values in addition to present or upcoming nutrient discharge limits prior to making decisions in sidestream and biosolids management.

As interest in hydrogen as an energy carrier has increased, the various ways that hydrogen is made are being categorized as “green,” “blue,” “gray,” and other colors in relation to their environmental impact. While these categorizations are somewhat useful to indicate the environmental and climate change impacts of different production pathways, they are not especially useful for policy making or industry decisionmaking purposes because they are subjective. For example, most definitions of green pathways for hydrogen production only include electrolysis from renewable electricity sources; however, Figure 1 indicates additional production pathways with some of these having near-zero or even negative greenhouse gas (GHG) emissions as well as low or no other emissions of concern. To help clarify the role of hydrogen in decarbonizing California, this brief summarizes the latest scientific findings from recent and in-progress research across the University of California Institute of Transportation Studies (UC ITS) concerning the relative carbon intensity (CI) of hydrogen production pathways. It also briefly covers the availability of biomass and biogas in California that could be applied to the production of low-CI hydrogen.

In 2015, California established a mandate that requires on-road greenhouse gas (GHG) emissions to be reduced by 40% below 1990 levels by 2030. We explore the feasibility of meeting this goal by large-scale commercialization of drop-in biofuels. Drop-in biofuels, although not clearly defined, are a class of fuels that can be produced from biomass and blended with either crude oil or finished fuels without requiring equipment retrofits. This article focuses on thermochemical routes at or near commercialization. We provide a bottom-up, spatially explicit cost analysis to evaluate whether California can meet its 2030 GHG reduction target with drop-in fuels alone. A takeaway from our analysis is that drop-in fuels, if their performance is consistent with small-scale and simulated results, can be viable low-carbon substitutes for gasoline and diesel. We find that California can meet, and even exceed, its 2030 GHG emissions target for on-road vehicles with drop-in biofuels alone, but this requires use of biomass resources located outside the state. Meeting the 40% reduction target in a cost-effective manner requires pyrolysis of herbaceous agricultural residues (96% of total fuel output) and the conversion of woody residues via methanol-to-gasoline (4%). This scale of production would require 58 million metric tons of biomass feedstock, or 20% of total available biomass residues in the United States. For comparison, California is responsible for 11% of transportation-related petroleum consumption in the US. The approximately 5 billion gallons (19 billion liters) per year of drop-in fuel would displace 30% of gasoline and 60% of diesel demand in California. If electricity offset credits are eliminated, the target can be met with a similar scale of production, but methanol-to-gasoline becomes the dominant route (>99%), biomass requirements increase by 33%, and average production costs increase by 20%. Following this policy pathway would increase national biofuel production by 30% relative to 2015 production levels.

Nonpotable water reuse (NPR) is one option for conserving valuable freshwater resources. Decentralization can improve distribution system efficiency by locating treatment closer to the consumer; however, small treatment systems may have higher unit energy and greenhouse-gas (GHG) emissions. This research explored the trade-off between residential NPR systems using a life-cycle approach to analyze the energy use and GHG emissions. Decentralized and centralized NPR options are compared to identify where decentralized systems achieve environmental advantages over centralized reuse alternatives, and vice versa, over a range of scales and spatial and demographic conditions. For high-elevation areas far from the centralized treatment plant, decentralized NPR could lower energy use by 29% and GHG emissions by 28%, but in low-elevation areas close to the centralized treatment plant, decentralized reuse could be higher by up to 85% (energy) and 49% (GHG emissions) for the scales assessed (20-2000 m3/day). Direct GHG emissions from the treatment processes were found to be highly uncertain and variable and were not included in the analysis. The framework presented can be used as a planning support tool to reveal the environmental impacts of integrating decentralized NPR with existing centralized wastewater infrastructure and can be adapted to evaluate different treatment technology scales for reuse.

Public transit systems with high occupancy can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. In previous work, we explored the unintended consequences of lowering transit LOS on emissions in a single-technology transit system. Herein, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, we provide a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and societal costs. We find that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We find that the potential for unintended consequences increases with the size of the city. Our results are robust to uncertainties in the costs and emissions parameters.

Public transit systems with efficient designs and operating plans can reduce greenhouse gas (GHG) emissions relative to low-occupancy transportation modes, but many current transit systems have not been designed to reduce environmental impacts. This motivates the study of the benefits of design and operational approaches for reducing the environmental impacts of transit systems. For example, transit agencies may replace level-of-service (LOS) by vehicle miles traveled (VMT) as a criterion in evaluating design and operational changes. Previous studies have demonstrated in an idealized singletechnology transit system the potential of reducing GHG emissions by lowering the transit level-of-service (LOS) provided to the users. In this research, we extend the analysis to account for a more realistic case: a transit system with a hierarchical structure (trunk and feeder lines) providing service to a city where demand is elastic. By considering the interactions between the trunk and the feeder systems, the study provides a quantitative basis for designing and operating integrated urban transit systems that can reduce GHG emissions and costs to both transit users and agencies. The study shows that highly elastic transit demand may cancel emission reduction potentials resulting from lowering LOS, due to demand shifts to lower occupancy vehicles, causing unintended consequences. However, for mass transit modes, these potentials are still significant. Transit networks with buses, bus rapid transit or light rail as trunk modes should be designed and operated near the cost-optimal point when the demand is highly elastic, while this is not required for metro. We also find that the potential for unintended consequences increases with the size of the city. The results are robust to uncertainties in the costs and emissions parameters. The study also includes a discussion of a current transit system. Since many current transit systems have not yet been optimally designed, it should be possible to reduce their GHG emissions without sacrificing the LOS. A case study of the MUNI bus system in San Francisco is used to validate this conjecture. The analysis shows that reductions in GHG emissions can be achieved when societal costs are reduced simultaneously. The cost-optimal MUNI bus system has a societal cost of 0.15 billion $/year and emits 1680 metric tons of greenhouse gases. These figures only amount to about half of the cost and a third of the emissions in the current MUNI bus system. The optimal system has a lower spatial availability but a higher temporal availability of bus service than the current system, which highlights the potential benefits of providing more frequent express bus services.

Transportation agencies are being urged to reduce their greenhouse gas (GHG) emissions. One possible solution within their scope is to alter their pavement management system to include environmental impacts. Managing pavement assets is important because poor road conditions lead to increased fuel consumption of vehicles. Rehabilitation activities improve pavement condition, but require materials and construction equipment, which produce GHG emissions as well. The agency's role is to decide when to rehabilitate the road segments in the network. In previous work, we sought to minimize total societal costs (user and agency costs combined) subject to an emissions constraint for a road network, and demonstrated that there exists a range of potentially optimal solutions (a Pareto frontier) with tradeoffs between costs and GHG emissions. However, we did not account for the case where the available financial budget to the agency is binding. This letter considers an agency whose main goal is to reduce its carbon footprint while operating under a constrained financial budget. A Lagrangian dual solution methodology is applied, which selects the optimal timing and optimal action from a set of alternatives for each segment. This formulation quantifies GHG emission savings per additional dollar of agency budget spent, which can be used in a cap-and-trade system or to make budget decisions. We discuss the importance of communication between agencies and their legislature that sets the financial budgets to implement sustainable policies. We show that for a case study of Californian roads, it is optimal to apply frequent, thin overlays as opposed to the less frequent, thick overlays recommended in the literature if the objective is to minimize GHG emissions. A promising new technology, warm-mix asphalt, will have a negligible effect on reducing GHG emissions for road resurfacing under constrained budgets.

With increased awareness of the emissions of greenhouse gases (GHGs) and the significant contribution from the cement industry, research efforts are being advanced to reduce the impacts associated with concrete production and consumption. A variety of methods have been proposed, one of the most common being the replacement of cement as a binder in concrete with supplementary cementitious materials, such as fly ash (FA), which can have lower environmental effects. The use of FA can change the kinetics of the hydration reactions and, consequently, modify the evolution of the concrete strength over time. Yet the influence of designing structural elements to obtain the required strength at later ages has not been examined in terms of their influence on global warming potential (GWP) of concrete. This research investigates the influence of design age, in addition to mix proportions and geometric aspects, on the GWP associated with making beams, columns, and a concrete building frame. Findings suggest that while the GWP for beams is not highly dependent on concrete mixture strength, the GWP for columns is dependent on strength, thus the influence of required strength at later ages influences GWP of making columns more so than beams. For the concrete frame analyzed, a potential 45% reduction in GWP, depending on mix proportions and design age, was found. Using the findings from this research, the GWP associated with production of concrete in California could be reduced by approximately 1.8 million metric tons of CO2-eq emissions, equivalent to approximately 2% of all industrial GHG emissions in California.

Passenger cars in the United States (U.S.) rely primarily on petroleum-derived fuels and contribute the majority of U.S. transportation-related greenhouse gas (GHG) emissions. Electricity and biofuels are two promising alternatives for reducing both the carbon intensity of automotive transportation and U.S. reliance on imported oil. However, as standalone solutions, the biofuels option is limited by land availability and the electricity option is limited by market adoption rates and technical challenges. This paper explores potential GHG emissions reductions attainable in the United States through 2050 with a county-level scenario analysis that combines ambitious plug-in hybrid electric vehicle (PHEV) adoption rates with scale-up of cellulosic ethanol production. With PHEVs achieving a 58% share of the passenger car fleet by 2050, phasing out most corn ethanol and limiting cellulosic ethanol feedstocks to sustainably produced crop residues and dedicated crops, we project that the United States could supply the liquid fuels needed for the automobile fleet with an average blend of 80% ethanol (by volume) and 20% gasoline. If electricity for PHEV charging could be supplied by a combination of renewables and natural-gas combined-cycle power plants, the carbon intensity of automotive transport would be 79 g CO2e per vehicle-kilometer traveled, a 71% reduction relative to 2013.

Vehicle manufacturing effects are critical life-cycle components in the total costs of vehicle travel and future manufacturing processes should be evaluated for travel forecasts. With efforts to introduce lightweight materials, increased fuel economy, and new technologies such as electric vehicles, understanding the energy and environmental effects of these expected vehicles is critical. Current vehicle manufacturing energy use and greenhouse gas emissions are summarized from existing research for passenger (conventional gasoline vehicles, hybrid electric vehicles, aircraft, high-speed rail) and freight (trucks, trains, and ocean going vessels) modes. Future vehicle manufacturing effects are then determined incorporating the aforementioned modes as well as plug-in hybrid and battery electric vehicles.

The US parking infrastructure is vast and little is known about its scale and environmental impacts. The few parking space inventories that exist are typically regionalized and no known environmental assessment has been performed to determine the energy and emissions from providing this infrastructure. A better understanding of the scale of US parking is necessary to properly value the total costs of automobile travel. Energy and emissions from constructing and maintaining the parking infrastructure should be considered when assessing the total human health and environmental impacts of vehicle travel. We develop five parking space inventory scenarios and from these estimate the range of infrastructure provided in the US to be between 105 million and 2 billion spaces. Using these estimates, a life-cycle environmental inventory is performed to capture the energy consumption and emissions of greenhouse gases, CO, SO2, NOX, VOC (volatile organic compounds), and PM10 (PM: particulate matter) from raw material extraction, transport, asphalt and concrete production, and placement (including direct, indirect, and supply chain processes) of space construction and maintenance. The environmental assessment is then evaluated within the life-cycle performance of sedans, SUVs (sports utility vehicles), and pickups. Depending on the scenario and vehicle type, the inclusion of parking within the overall life-cycle inventory increases energy consumption from 3.1 to 4.8 MJ by 0.1–0.3 MJ and greenhouse gas emissions from 230 to 380  g CO2e by 6–23 g CO2e per passenger kilometer traveled. Life-cycle automobile SO2 and PM10 emissions show some of the largest increases, by as much as 24% and 89% from the baseline inventory. The environmental consequences of providing the parking spaces are discussed as well as the uncertainty in allocating paved area between parking and roadways.

A life-cycle energy consumption analysis of a Bridgeport manual mill and a Mori Seiki DuraVertical 5060 has been conducted. The use phase incorporated three manufacturing environments: a community shop, a job shop, and a commercial facility. The CO2-equivalent emissions were presented per machined part. While the use phase comprised the majority of the overall emissions, the manufacturing phase emissions were significant especially for the job shop, which is not as efficient as the other facilities due to its inherent need for flexibility. Since the Mori Seiki is heavier, the manufacturing phase of this machine tool had a greater impact on emissions than the Bridgeport. Transportation was small relative to the use phase, which was dominated by cutting, HVAC, and lighting. These results highlight areas for energy reductions in machine tool design as well as the importance of facility type to the manufacture of any product.

Pavements comprise an essential and vast infrastructure system supporting our transportation network, yet their impact on the environment is largely unquantified. Previous life-cycle assessments have only included a limited number of the applicable life-cycle components in their analysis. This research expands the current view to include eight different components: materials extraction and production, transportation, onsite equipment, traffic delay, carbonation, lighting, albedo, and rolling resistance. Using global warming potential as the environmental indicator, ranges of potential impact for each component are calculated and compared based on the information uncovered in the existing research. The relative impacts between components are found to be orders of magnitude different in some cases. Context-related factors, such as traffic level and location, are also important elements affecting the impacts of a given component. A strategic method for lowering the global warming potential of a pavement is developed based on the concept that environmental performance is improved most effectively by focusing on components with high impact potentials. This system takes advantage of the fact that small changes in high-impact components will have more effect than large changes in low-impact components.

In recent years, the reduction of freight truck trips has been a common policy goal. To this end, policies aimed at influencing load consolidation, load factors and increasing maximum truck weight limits have been suggested and implemented, resulting in higher gross vehicle weights. The purpose of such policies has generally been to mitigate congestion and environmental impacts. However, trucks cause most of the damage incurred by pavements. The supply chain associated with pavement maintenance and construction releases significant air emissions, raising the question of whether increased vehicle weights may cause unintended environmental consequences. This paper presents scenarios with estimated emissions resulting from load consolidation and changes in load factors. These scenarios reveal several points having to do with the tradeoff between tailpipe versus pavement supply‐chain emissions. In some cases, unintended emissions from the pavement supply‐chain are found to be significant. Emissions associated with pavement construction are also found to increase as a result of pavement design specifications that account for heavier trucks.

The development of life-cycle energy and emissions factors for passenger transportation modes is critical for understanding the total environmental costs of travel. Previous life-cycle studies have focused on the automobile given its dominating share of passenger travel and have included only few life-cycle components, typically related to the vehicle (i.e., manufacturing, maintenance, end-of-life) or fuel (i.e., extraction, refining, transport). Chester (2009) provides the first comprehensive environmental life-cycle assessment of not only vehicle and fuel components but also infrastructure components for automobiles, buses, commuter rail systems, and aircraft. Many processes were included for vehicles (manufacturing, active operation, inactive operation, maintenance, insurance), infrastructure (construction, operation, maintenance, parking, insurance), and fuels (production, distribution). The vehicles inventoried were sedans, pickups, SUVs, urban diesel buses, light rail (San Francisco’s Muni Metro and Boston’s Green Line, both electric), heavy rail (San Francisco Bay Area’s BART and Caltrain), and aircraft (small, medium, and large-sized planes are disaggregated). Given the methodological framework in Chester (2009), the question of applicability of these systems to other U.S. modes, and the data availability of other modes, is extended in this study to motorcycles, light duty diesel vehicles, school buses, electric buses, Chicago commuter rail modes, and New York City commuter rail modes.

The passenger transportation modes of rail and air are critical systems relied upon for business and leisure. When considering their environmental effects, most studies and policy focus on the fuel use of the vehicles, and ignore the energy and other resource inputs and environmental outputs from the life cycles of other components. Vehicle manufacturing and maintenance, infrastructure construction and operation, and fuel production are rarely included in environmental factors for transportation systems.The goal of this project is to develop a comprehensive life-cycle assessment model to quantify the energy inputs and emissions from rail and air transportation in the U.S. associated with the life-cycle components (raw materials extraction, manufacturing, construction, operation, maintenance) of the vehicles, infrastructures, and fuels involved in these systems. Energy inputs are quantified as well as greenhouse gas and criteria air pollutant outputs. Inventory results are normalized to effects per passenger-mile traveled.Results show that energy and greenhouse gas emissions increase by as much as 2.1 times for heavy rail, 1.4 times for high speed rail, and 1.3 times for air when life-cycle components are included. Criteria air pollutant emissions increase between 1.1-29 times for heavy rail, 1.2-1.4 times for high speed rail, and 1.5-9 times for air.

Cooling buildings with large airflow rates of outside air when temperatures are favorable is an established energy-saving measure. In data centers, this strategy is not widely used, owing to concerns that it would cause increased indoor levels of particles of outdoor origin, which could damage electronic equipment. However, environmental conditions typical of data centers and the associated potential for equipment failure are not well characterized. This study presents the first published measurements of particle concentrations in operating data centers. Indoor and outdoor particle measurements were taken at eight different sites in northern California for particulate matter 0.3-5.0 μm in diameter. One of the data centers has an energy-efficient design that employs outside air for cooling, while the rest use conventional cooling methods. Ratios of measured particle concentrations in the conventional data centers to the corresponding outside concentrations were significantly lower than those typically found in office or residential buildings. Estimates using a material-balance model match well with empirical results, indicating that the dominant particle sources and losses have been identified. Measurements taken at the more energy-efficient site show nearly an order of magnitude increase in particle concentration when ventilation rates were high. The model indicates that this increase may be even higher when including particles smaller than the monitoring-equipment size limitation. Even with the increases, the measured particle concentrations are still below concentration limits recommended in industry standards. © 2008 Elsevier Ltd.

The passenger transportation modes of auto, bus, heavy rail, light rail and air are critical systems relied upon for business and leisure. When considering their environmental effects, most studies and policy focus on the fuel use of the vehicles, and ignore the energy and other resource inputs and environmental outputs from the life cycles of necessary infrastructures, fuels, and vehicles. The goal of this project is to develop comprehensive life-cycle assessment (LCA) models to quantify the energy inputs and emissions from autos, buses, heavy rail, light rail and air transportation in the U.S. associated with the entire life cycle (design, raw materials extraction, manufacturing, construction, operation, maintenance, end-of-life) of the vehicles, infrastructures, and fuels involved in these systems. Energy inputs are quantified as well as greenhouse gas and criteria air pollutant outputs. Inventory results are normalized to effects per vehicle-lifetime, VMT, and PMT. Current results show that total energy and greenhouse gas emissions increase by as much as 1.6X for automobiles, 1.4X for buses, 2.6X for light rail, 2.1X for heavy rail, and 1.3X for air over operation. Criteria air pollutant emissions increase up to 30X for automobiles, 7X for buses, 10X for light rail, 29X for heavy rail, and 9X for air.This working paper is superceded by UCB-ITS-DS-2008-1, the Ph.D. dissertation of Mikhail Vin Chester.

With the emergence of extended producer responsibility regulations for electronic devices, it is becoming increasingly important for electronics manufacturers to apply design for recycling (DFR) methods in the design of plastic enclosures. This paper presents an analytical framework for quantifying the environmental and economic benefits of DFR for plastic computer enclosures during the design process, using straightforward metrics that can be aligned with corporate environmental and financial performance goals. The analytical framework is demonstrated via a case study of a generic desktop computer enclosure design, which is recycled using a typical US "take-back" system for plastics from waste electronics. The case study illustrates how the analytical framework can be used by the enclosure designer to quantify the environmental and economic benefits of two important DFR strategies: choosing high-value resins and minimizing enclosure disassembly time. Uncertainty analysis is performed to quantify the uncertainty surrounding economic conditions in the future when the enclosure is ultimately recycled.

The passenger transportation modes of auto, bus, heavy rail, light rail and air are critical systems relied upon for business and leisure. When considering their environmental effects, most studies and policy focus on the fuel use of the vehicles, and ignore the energy and other resource inputs and environmental outputs from the life cycles of necessary infrastructures, fuels, and vehicles. The goal of this project is to develop comprehensive life-cycle assessment (LCA) models to quantify the energy inputs and emissions from autos, buses, heavy rail, light rail and air transportation in the U.S. associated with the entire life cycle (design, raw materials extraction, manufacturing, construction, operation, maintenance, end-of-life) of the vehicles, infrastructures, and fuels involved in these systems. Energy inputs are quantified as well as greenhouse gas and criteria air pollutant outputs. Inventory results are normalized to effects per vehicle-lifetime, VMT, and PMT. Current results show that energy and greenhouse gas emissions increase by as much as 1.3X for automobiles, 1.4X for buses, 2.6X for light rail, 2.1X for heavy rail, and 1.3X for air. Criteria air pollutant emissions increase up to 25X for automobiles, 7X for buses, 220X for light rail, 98X for heavy rail, and 11X for air.This working paper is superceded by UCB-ITS-DS-2008-1, the Ph.D. dissertation of Mikhail Vin Chester.

Goal, Scope and Background. LEED (Leadership in Energy and Environmental Design) is a scoring system that evaluates the environmental friendliness of,buildings. It is composed of 69 credits, each one providing a score of one (i.e., one point) if implemented. However, since each credit does not always provide the same type and magnitude of benefits for the environment, a higher rating is not always synonymous with lower impacts. The goal of this paper is to evaluate the actual extent of the benefits and burdens of LEED, identify the critical credits and develop a new scale that will correct these miscorrelations.Methods. The various LEED credits are qualitatively analysed. It is possible to quantify the actual outcomes and thus perform a lifecycle assessment (LCA) on 45 credits applied to an actual California office building. This allows comparing the benefits of the different credits among each other. Commuting of the employees is included in the system. The LCA is performed with the help of SimaPro 7, combining the ecoinvent 1.2 inventory database and the impact assessment methodology IMPACT 2002+ v2.1, adapted to North America. Impacts are evaluated for human health, ecosystems quality, climate change, and resource consumption. Impacts of the different credits are aggregated in one indicator to allow the design of a new scoring system that assigns to the different credits an amount of points (i.e., a score) that are related to the actual benefits. A school and a residential building are also modeled in order to perform a sensitivity study.Results and Discussion. Operation, especially employee commuting and electricity consumption, dominates the impacts associated with the building. It appears that waste generation have limited but not negligible impacts, whereas water consumption has small impacts. Since the building is situated in California, heating is not an important source of impacts. As a result, credits that provide the most environmental benefits are the ones geared toward increasing the fraction of green electricity, reducing energy consumption, reducing employee commuting, and increasing waste recycling, along with the ones favoring the reuse and recycling of the building structure. The ones targeting reduction of water and land use, and recycling content in the furniture appear to be less beneficial. The scores of the different LEED credits range from -128 to 606. Negative credits are due to credits that lead to more burdens than benefits, for example, the one requiring the construction of a multifloor parking lot (with a score of -128). The most beneficial credit (with a score of 606) is the one requiring that electricity comes from at least 50% green power.Conclusions and Outlook. Comparing the new scale with the observations on site shows that the LEED credits actually implemented are not always the most beneficial for the environment. This issue should be addressed in order to make LEED more efficient. The proposed rating system should help correct these discrepancies. The amount of reduction in employee commuting that the related credits really achieve, actual impacts of land and water use, along with the benefits of improved indoor air quality are among the main future challenges of the present study.

This paper presents a discussion directed at determining the most progressive options for shifting the freight logistics industry towards having more sustainable-oriented goals. The authors first discuss transportation sustainability and the concept of green logistics. This is followed by a discussion on externalities resulting from vehicle emissions and indirect environmental externalities. The problem of environmental externalities is then examined, with focus on emissions and other related data. The authors then examine options for reducing environmental externalities. They discuss impact considerations, options focused on emissions reduction, changing freight sector operations, and considerations regarding demand and economic development.

The use of an indicator that is based on global climate change effects is important to support decision-makers committed to sustainable development. Our project demonstrated the use of life-cycle assessment (LCA) as a systematic approach to analyzing the construction and upgrade, operation, maintenance, and ultimate decommissioning of electric power plants. A case study of a hydroelectric power plant (Glen Canyon) was completed, including sensitivity analysis.The LCA performed in this research quantified emissions during different phases of the life of a power plant. The emissions of greenhouse gases (GHGs) were then characterized using the global warming potential (GWP) method. GWP is a method to compare the global climate change effects of different GHGs to that of CO2. It provides a relative assessment of impacts based on selection of specific time frames. However, because the GWP compares the potential impacts of any GHG to the potency of CO2, we decided to use a different name for our indicator that assesses the potential impact of electricity generation technologies. The global warming effect (GWE) combines LCA and GWP, and was used in comparative assessments of electricity generation technologies.

The public, industry and governments have become increasingly interested in green design and engineering as approaches towards better environmental quality and sustainable development. Pavement construction is one of the largest consumers of natural resources. Recycling of pavements represents an important opportunity to save the mining and use of virgin materials, conserve energy, divert materials away from landfills, and save scarce tax dollars. How much pollution, energy, natural resources, and money could be saved by using secondary materials in road construction? What are the engineering limits of using recycled materials in roads? Can we recycle over and over again pavements that contain rubber, glass, and other secondary materials? This research will quantify the environmental and economic costs and benefits of recycling asphalt pavements, and using secondary materials for their construction. The impacts will be traced through the related life-cycles and supply chains for material and energy inputs, water consumption, hazardous and non-hazardous waste generation, toxic discharges, and greenhouse gas as well as particulate matter emissions. Life-cycle environmental and economic assessment methods will be coupled with construction process models. Stakeholders will be able to use the resulting computer tool for decision-making and scenario analysis as parameters of the pavement recycling model change over time and from region to region.

Reducing the environmental effects of construction is a continuing professional and social concern to promote sustainable development. In this paper, we estimate the major commodity and service inputs, resource requirements, and environmental emissions and wastes for four major U.S. construction sectors as defined by the Department of Commerce: (1) highway, bridge, and other horizontal construction [0.6% of the 1992 U.S. gross domestic product (GDP)]; (2) industrial facilities and commercial and office buildings (1.5% of GDP); (3) residential one-unit buildings (1.9% of GDP); and (4) other construction (towers, water, sewer and irrigation systems, railroads, etc.) (2.4% of GDP). Our estimates include the entire supply chain of material, energy, and service suppliers for these sectors with the use of a detailed 1992 input-output model of the U.S. economy and publicly available environmental data. We find that in general, the four major U.S. construction sectors appear to use fewer resources and have lower rates of environmental emissions and wastes than their share of the GDP might suggest.