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Indicators of sustainability and environmental performance can be useful for comparing modes, discerning trends, and formulating appropriate policies. This paper considers the performance of U.S. transportation service sectors through use of 1992 and 1997 benchmark input–output models. Use of these models permits assessment of not only the direct performance of the sectors but also the supply chain impacts required for operation of the transportation sectors. Consideration of indirect impacts is critical for assessment of the overall costs and impacts of particular products or services. Six transportation service sectors (air, rail, water, truck, transit, and pipeline) are examined. Economic impact, energy, greenhouse gas emissions, and toxic emissions are examined. The transportation sectors use large amounts of energy, both in total and per dollar of output and on a per service basis. Pipeline and water transportation have particularly large energy requirements per dollar of output, likely reflecting higher energy intensity and lower labor intensity in these modes. Truck transportation is the most energy intensive of the freight transportation modes per ton-mile of service, but it has a trend toward greater energy efficiency. For greenhouse gas emissions, truck, water, and air transportation have the highest emissions per dollar of output. Water transportation freight rates are sufficiently low that emissions on a per ton-mile basis would be correspondingly low. Finally, the supply chain (indirect) toxic emissions per dollar of output are highest for rail and pipeline transportation. There is considerable work to be done to improve the overall sustainability of the different transportation modes.

In this study, a mixed integer linear programming model that integrates multimodal transport—truck and rail—into the switchgrass-based bioethanol supply chain was formulated. The objective of this study was to minimize the total cost for cultivation and harvesting, infrastructure, the storage process, bioethanol production, and transportation. Strategic decisions, including the number and location of intermodal facilities and biorefineries, and tactical decisions, such as the amount of biomass shipped, processed, and converted into bioethanol, were validated by using North Dakota as a case study. It was found that the multimodal transport scenario was more cost effective than a single mode of transport (truck) and resulted in a lower cost for bioethanol. A sensitivity analysis was conducted to demonstrate the impact of key factors in the decision to use multimodal transport in a switchgrass-based bioethanol supply chain and on the cost of bioethanol.

The paper analyses the impact of Electric Vehicle(EV) integration into different power systems and their flexibility potential in mitigating the uncertainty and variability of renewable Energy sources (RES) generation. The problem is cast as Mixed Integer Linear Programming (MILP) unit ommitment, modelling different generation mix/technologies over a number of scenarios. The results, as expected, show that different EV charging strategies have different impacts on power system operation and unit scheduling. In addition, the analyses support the premises that the greater number of EVs, with coordinated charging strategies, can have environmental enefits in terms of reducing CO2 emissions in addition to reducing wind curtailment and system operation costs. These benefits are more obvious in low flexible power systems characterized by dominantly thermal power plants, while they are less pronounced in balanced hydro thermal systems.

Marine spatial planning (MSP) in Europe is in a paradigm shift as all (coastal) European countries now have established practices for the production of marine spatial plans. Though international guidelines and an EU directive for MSP provides policy frameworks, the formulation of national policy designs for MSP remains a national responsibility resulting in vastly different practices. Focusing on three Northern European countries; Denmark, Germany and Norway, this paper presents examples of how national policy designs for marine spatial planning are structured, and how the current practice in each country is influenced by local planning cultures. This mapping gives insights to a number of challenges facing planning authorities when planning for sustainable development. Ambiguity dominates the framework of marine spatial planning and the central sustainability concepts it contains. This paper gives voice to the planning teams, as they are key-players in generating meaning in this ocean of ambiguity, giving insights to their understanding of sustainability in the planning of futures for sustainable seas.

As the largest renewable electricity source, hydropower represents an alternative to fossil fuels to achieve a low-carbon future. However, increasing evidence suggests that hydropower reservoirs are an important source of biogenic greenhouse gases (GHGs), albeit with large uncertainties. Combining spatially resolved assessments of GHG fluxes and hydroelectric capacity databases, we assessed that global GHG emissions from reservoirs is 0.38 Pg CO2 eq.yr−1, accounting for 1.0% of global anthropogenic emissions. The median carbon intensity for hydropower is ∼63.0 kg CO2eq. MWh−1, which is lower than that for fossil fuels, but higher than that for other renewable energy sources. High carbon intensity is mostly linked to shallow (water storage depth <20 m) and eutrophic reservoirs. Furthermore, we found that the reservoir carbon intensity (CI) value would be markedly increased to 131.5 kg CO2eq. MWh−1 when considering the dams under construction and planning. A low-carbon future will benefit from optimal dam planning and management measures, i.e., applying sludge removal treatments, thereby reducing the proportion of shallow reservoirs and anthropogenic pollution.

Despite the fact that microgrids are growing in popularity, their integration in distribution networks is problematic because of the omnipresent variability of renewable energy sources. New research focuses on viewing microgrids as having an active role in the system and providing additional services, such as the concept of low-carbon microgrid nodes. The paper presents a mixed integer linear programming optimization algorithm for determining the optimal size of the distributed generation unit and battery storage system based on operational savings and investment costs, as well as estimation of environmental benefits. The flexibility of the analyzed power node comes not only from its capability to store electricity in the battery banks but to optimally schedule flexible loads such as electric vehicles (EVs). Stochasticity of EV arrival and their state of charge are modeled daily and seasonally. The results show that active market signal-driven integration of such nodes is still not feasible without incentives. But as additional services start creating profits, the gap to feasibility will become smaller.

Many cities in the United States are facing challenges associated with antiquated urban arterials, whose purpose has changed greatly since their development. Once considered the main streets of the city, with thriving businesses and attractive residential development, many have deteriorated over the decades for a number of reasons, including shifting demand for housing and retail development and the construction of parallel high-speed urban expressways. Because of the complexity of the problems associated with these arterials, a great challenge of transportation and land use planners is to develop a systems-level approach to revitalize and reinvent these arterials in a manner that encourages environmental, economic, and social sustainability. Presented is a methodology to revitalize multimodal urban arterials that includes land use planning, traffic and transit operations management, street redesign, and community participation to improve the conditions of such arterials. Analysis is carried out by using these principles on San Pablo Avenue, a major arterial in the San Francisco Bay Area in California. By using these analysis techniques, land use and transportation recommendations are made that will facilitate sustainable development along this corridor.

This paper explores the utility of qualitative scenario approaches to examine the potential impacts of climate change on marine biodiversity conservation on the east coast of Australia. This region is large and diverse, with considerable variation in marine biodiversity and, concomitantly, considerable diversity in the likely impacts from climate change. The results reinforce a number of key points. Engaging with stakeholders in scenario planning provides not only a focus to discuss the future in a disciplined way, but also provides ongoing reference points for contemporary decision making and planning. The paper illustrates how qualitative scenario planning provides opportunities to address the challenges of marine biodiversity conservation in a changing environment.

This paper analyzes the relationships between the speed of passenger trains (especially high-speed trains), their energy consumption, and their greenhouse gas emissions. After an outline of the special energy consumption characteristics of high-speed railway systems, the amounts of energy consumed by conventional and high-speed passenger railway systems are compared. The comparison includes an empirical verification of the differences between high-speed and conventional rail systems and an analysis based on theoretical models. It is shown that, on average, high-speed railway systems usually consume 29% less energy than conventional railway systems. With a comparison of the levels of energy consumption and emissions of high-speed passenger trains with those of all other modes of transportation with which it competes (including conventional passenger trains), the net effects on emissions of high-speed train service on any corridor in the study can be analyzed. This is important because even if the difference in the energy consumption of the Spanish high-speed rail system, Alta Velocidad Española (AVE), and that of conventional rail system is not significant or even if AVE consumes more energy, the diversion of passengers from air travel ultimately yields significant reductions in energy consumption and emissions on a route. The study concludes that each high-speed train passenger accounts for an emissions reduction of approximately 30 kg of CO2 and that this reduction increased on the routes on which AVE reaches higher speeds.