The impact of plug-in vehicles on greenhouse gas and criteria pollutants emissions in an urban air shed using a spatially and temporally resolved dispatch model

With the introduction of plug-in vehicles (PEVs) into the light-duty vehicle fleet, the tail-pipe emissions of GHGs and criteria pollutants will be partly transferred to electricity generating units. To study the impact of PEVs on well-to-wheels emissions, the U.S. Western electrical grid serving the South Coast Air Basin (SoCAB) of California is modeled with both spatial and temporal resolution at the level of individual power plants. Electricity load is calculated and projected for future years, and the temporal electricity generation of each power plant within the SoCAB is modeled based on historical data and knowledge of electricity generation and dispatch.Due to the efficiency and pollutant controls governing the performance of the Western grid, the deployment of PEVs results in a daily reduction of greenhouse gases (GHGs) and tail-pipe emissions, especially in the critical morning and afternoon commute hours. The extent of improvement depends on charging scenarios, future grid mix, and the number and type of plug-in vehicles. In addition, charging PEVs using wind energy that would otherwise be curtailed can result in a substantial emissions reduction. Smart control will be required to manage PEV charging in order to mitigate renewable intermittencies and decrease emissions associated with peaking power production.     

Reducing the fuel use and greenhouse gas emissions of the US vehicle fleet

The unrelenting increase in the consumption of oil in the US light-duty vehicle fleet (cars and light trucks) presents an extremely challenging energy and environmental problem. A variety of propulsion technologies and fuels have the promise to reduce petroleum use and greenhouse gas emissions from motor vehicles. Even so, achieving a noticeable reduction on both fronts in the near term will require rapid penetration of these technologies into the vehicle fleet, and not all alternatives can meet both objectives simultaneously. Placing a much greater emphasis on reducing fuel consumption rather than improving vehicle performance can greatly reduce the required market penetration rates. Addressing the vehicle performance–size–fuel consumption trade-off should be the priority for policymakers rather than promoting specific vehicle technologies and fuels.     

Hydrogen storage technology options for fuel cell vehicles: Well-to-wheel costs, energy efficiencies, and greenhouse gas emissions

Five different hydrogen vehicle storage technologies are examined on a Well-to-Wheel basis by evaluating cost, energy efficiency, greenhouse gas (GHG) emissions, and performance. The storage systems are gaseous 350 bar hydrogen, gaseous 700 bar hydrogen, Cold Gas at 500 bar and 200 K, Cryo-Compressed Liquid Hydrogen (CcH2) at 275 bar and 30 K, and an experimental adsorbent material (MOF 177) -based storage system at 250 bar and 100 K. Each storage technology is examined with several hydrogen production options and a variety of possible hydrogen delivery methods. Other variables, including hydrogen vehicle market penetration, are also examined. The 350 bar approach is relatively cost-effective and energy-efficient, but its volumetric efficiency is too low for it to be a practical vehicle storage system for the long term. The MOF 177 system requires liquid hydrogen refueling, which adds considerable cost, energy use, and GHG emissions while having lower volumetric efficiency than the CcH2 system. The other three storage technologies represent a set of trade-offs relative to their attractiveness. Only the CcH2 system meets the critical Department of Energy (DOE) 2015 volumetric efficiency target, and none meet the DOE’s ultimate volumetric efficiency target. For these three systems to achieve a 480-km (300-mi) range, they would require a volume of at least 105-175 L in a mid-size FCV.     

The impact of fuel cell vehicle deployment on road transport greenhouse gas emissions: The China case

Considerable attention has been paid to energy security and climate problems caused by road vehicle fleets. Fuel cell vehicles provide a new solution for reducing energy consumption and greenhouse gas emissions, especially those from heavy-duty trucks. Although cost may become the key issue in fuel cell vehicle development, with technological improvements and cleaner pathways for hydrogen production, fuel cell vehicles will exhibit great potential of cost reduction. In accordance with the industrial plan in China, this study introduces five scenarios to evaluate the impact of fuel cell vehicles on the road vehicle fleet greenhouse gas emissions in China. Under the most optimistic scenario, greenhouse gas emissions generated by the whole fleet will decrease by 13.9% compared with the emissions in a scenario with no fuel cell vehicles, and heavy-duty truck greenhouse gas emissions will decrease by nearly one-fifth. Greenhouse gas emissions intensity of hydrogen production will play an essential role when fuel cell vehicles' fuel cycle greenhouse gas emissions are calculated; therefore, hydrogen production pathways will be critical in the future.     

Long-term greenhouse gas emission and petroleum reduction goals: Evolutionary pathways for the light-duty vehicle sector

To meet long-term environmental and energy security goals, the United States must reduce petroleum use in the light-duty vehicle fleet by 70% and greenhouse gas emissions by a factor of ten compared to business-as-usual growth projections for the year 2050. A wedge-based approach was used to quantify the scope of the problem in real terms, and to develop options for meeting mid-century targets. Four mitigation mechanisms were considered: (1) improvements in near-term vehicle technologies; (2) emphasis on low-carbon biofuels; (3) de-carbonization of the electric grid; and (4) demand-side travel-reduction initiatives. Projections from previous studies were used to characterize the potential of individual mitigation mechanisms, which were then integrated into a light-duty vehicle fleet model; particular emphasis was given to systemic constraints on scale and rates of change.     

A tank in series model for alkaline fuel cell in cogeneration of hydrogen peroxide and electricity

This work presents a Tank in Series Reactor (TSR) model for the alkaline fuel cell operating in potentiostatic mode in cogeneration of H₂O₂ and electricity. The developed TSR model accounts for the component and the energy balances in gas channels, liquid alkaline and catalyst layers together with charge balances at electrode/electrolyte interfaces. The TSR model is able to predict the limiting two-dimensional profiles in alkaline fuel cell. The simulation results indicate the influence of mass transfer on the distribution of concentration, temperature and current density.     

Hydrogen gas dispersion studies for hydrogen fuel cell vessels II: Fuel cell room releases and the influence of ventilation

Results are presented for computational fluid dynamics (CFD) modeling for varying hydrogen leaks within a hydrogen vessel's Fuel Cell Rack inside a Fuel Cell Room. In the limiting case of no room ventilation, modeling shows that the flammable region produced by the hydrogen leak is initially limited by self-induced entrainment and recirculation of air caused by the buoyant rising of hydrogen. Locally and at shorter times (minutes), this effect can be even more influential in limiting the size of the flammable envelope than Fuel Cell Room ventilation. Interestingly, the more diffuse detectable (but sub-flammable) region is not self-limited. This indicates the recirculation pattern required for the self-limiting effect requires a sufficient concentration of hydrogen to establish and differentiate the rising hydrogen mass from the surrounding air, thereby establishing the recirculation pattern that self-limits the flammable region at short times. Modeling results with the Fuel Cell Room ventilation activated shows that several seconds after a hydrogen leak is initiated, the flammable region reaches a steady state, with only minor fluctuations due to the air currents created by ventilation. The expected trends with ventilation rate are found: for a given leak size, a decreasing flammable envelope is found as ventilation is increased and for a given level of ventilation, an increasing hydrogen leak rate produces a larger flammable region. For the cases and ventilation rates examined, flammable H₂/air mixtures greater than 4% clear the Fuel Cell Room within 1.5 s after the hydrogen leak is turned off. The CFD modeling results for the detectable level of hydrogen that would trigger an alarm showed that higher ventilation rates might have the unintended consequence of making a hydrogen leak harder to detect, depending on the location of the gas detector in the Fuel Cell Room For the hydrogen leak rates considered in this study, we find that a ventilation rate of 15 ACH provides timely hydrogen evacuation while allowing the leak to be detected by the ceiling-mounted hydrogen monitor (for most monitor locations).     

Sustainable practices: Solar hydrogen fuel and education program on sustainable energy systems

Owing to the increasingly apparent climate change, it becomes imperative to use renewable energy in the production of fuel that is environmentally friendly. At the same time, there is a need to introduce the related education programs to develop the skills of the technical staff working at the front line of rapidly developing renewable energy technologies.     

Effect of hydrogen addition on criteria and greenhouse gas emissions for a marine diesel engine

Hydrogen remains an attractive alternative fuel to petroleum and a number of investigators claim that adding hydrogen to the air intake manifold of a diesel engine will reduce criteria emissions and diesel fuel consumption. Such claims are appealing when trying to simultaneously reduce petroleum consumption, greenhouse gases and criteria pollutants. The goal of this research was to measure the change in criteria emissions (CO, NO_x, and PM_2.5) and greenhouse gases such as carbon dioxide (CO₂), using standard test methods for a wide range of hydrogen addition rates. A two-stroke Detroit Diesel Corporation 12V-71TI marine diesel engine was mounted on an engine dynamometer and tested at three out of the four loads specified in the ISO 8178-4 E3 emission test cycle and at idle. The engine operated on CARB ultra-low sulfur #2 diesel with hydrogen added at flow rates of 0, 22 and 220 SLPM.     

Microalgae-microbial fuel cell (mMFC): an integrated process for electricity generation,wastewater treatment,CO2 sequestration and biomass production

The world today is facing a crisis of energy and environmental pollution. Conventional or photosynthetic microbial fuel cell (MFC) is an advanced “green” energy technology that utilizes living microorganisms to convert biochemical or light energy into electricity through metabolic reaction and photosynthesis, offering a potential solution for the above-mentioned crisis. Further incorporating microalgae into MFC, microalgae-microbial fuel cell (mMFC) integrates electricity generation, wastewater treatment, CO₂ sequestration and biomass production in a single, self-sustainable technology. This review first describes the fundamentals of MFC as well as its applications in treating domestic, municipal, agricultural and industrial wastewaters. Then, mMFC-based configurations and applications with its advantages compared with MFC are explained in particular, together with the parameters governing its performance. Lastly, the opportunities and challenges involved in the development of mMFCs are also explored.     

Transportation options in a carbon-constrained world: Hybrids,plug-in hybrids,biofuels, fuel cell electric vehicles,and battery electric vehicles

Multiple alternative vehicle and fuel options are being proposed to alleviate the threats of climate change, urban air pollution, and oil dependence caused by the transportation sector. We report here on the results from an extensive computer model developed over the last decade to simulate and compare the societal benefits of deploying various alternative transportation options including hybrid electric vehicles and plug-in hybrids fueled by gasoline, diesel fuel, natural gas, and ethanol, and all-electric vehicles powered by either batteries or fuel cells. These simulations compare the societal benefits over a 100-year time horizon of each vehicle/fuel combination in terms of reduced local air pollution, greenhouse gas pollution, and oil consumption compared to gasoline cars.     

Spatial and temporal optimization of hydrogen fuel supply chain for light duty passenger vehicles in British Columbia

British Columbia is well positioned to capitalize on its natural resources and its carbon policies towards the development of a hydrogen fueling network. A multi-period optimization model was developed to design a hydrogen fuel supply chain based on a mixed integer linear programming formulation. The model was applied to the light duty passenger vehicle sector in British Columbia under three hydrogen demand scenarios. As part of the objective function, the model incorporated the current provincial emissions mitigation policies, i.e., a carbon tax and a low-carbon fuel standard (LCFS). Based on cost, our model indicates that steam methane reforming (SMR) is the least costly hydrogen production technology even with carbon policies in place. However, SMR would result in higher emissions (compared to other pathways). Coupling the carbon tax with the LCFS can be a suitable policy option when hydrogen price and GHG emissions are weighted equally.     

An energy matching method for battery electric vehicle and hydrogen fuel cell vehicle based on source energy consumption rate

The smart cities development requires reducing energy consumption and using as much renewable energy as possible, so the widespread use of new energy vehicles is a very important measure. In this work, for the energy system configuration and energy efficiency balance of new energy vehicles, we propose an energy matching method to study its energy efficiency from the view point for energy life cycle. Nowadays, new energy vehicles mainly include battery electric vehicles (BEV) and hydrogen fuel cell vehicles (HFCEV). Firstly, we proposed the Source to Range (STR) model. Then, based on STR model, we used energy efficiency analysis chart to visually represent the conversion, delivery and consumption of the vehicle energy life cycle. Furthermore, we proposed a Source Energy Consumption Rate (SECR), which is used to evaluate the vehicles energy efficiency. Finally, based on STR model, we obtained the dividing line of the same SECR for new energy vehicles and equivalent fuel vehicles, which provides constraints on the vehicle energy system design. The results show that STR model can provide an effective tool for energy matching and energy efficiency analysis of new energy vehicles, and has a reference for product development of new energy vehicles.     

A dual objective global optimization algorithm based on adaptive weighted hybrid surrogate model for the hydrogen fuel utilization in hydrogen fuel cell vehicle

Current engineering optimizations mainly use surrogate models (SMs) to approximate complex black-box problems. However, SMs with different approximate characteristics may make the designers unable to accurately judge which type of SMs is more suitable for the actual optimization design. A reasonable combination of different SMs might be one of the solutions. To this end, a global optimization algorithm based on an adaptive weighted hybrid surrogate model (GOA-AWHS) is proposed. In each iteration, a hybrid model based on kriging and RBF is first constructed by adaptively selecting weight coefficients. Next, two objectives consisting of predicted objective, root mean square error and distance parameters are optimized to generate the Pareto frontier. Finally, further selection of data points on the Pareto front yields multiple promising optimal solutions. A series of standard numerical functions and hydrogen fuel utilization in hydrogen fuel cell vehicles are tested to demonstrate the effectiveness and robustness of the GOA-AWHS method.     

Scenario analysis on alternative fuel/vehicle for China’s future road transport: Life-cycle energy demand and GHG emissions

The rapid growth of vehicles has resulted in continuing growth in China’s oil demand. This paper analyzes future trends of both direct and life cycle energy demand (ED) and greenhouse gas (GHG) emissions in China’s road transport sector, and assesses the effectiveness of possible reduction measures by using alternative vehicles/fuels. A model is developed to derive a historical trend and to project future trends. The government is assumed to do nothing additional in the future to influence the long-term trends in the business as usual (BAU) scenario. Four specific scenarios are used to describe the future cases where different alternative fuel/vehicles are applied. The best case scenario is set to represent the most optimized case. Direct ED and GHG emissions would reach 734 million tonnes of oil equivalent and 2384 million tonnes carbon dioxide equivalent by 2050 in the BAU case, respectively, more than 5.6 times of 2007 levels. Compared with the BAU case, the relative reductions achieved in the best case would be 15.8% and 27.6% for life cycle ED and GHG emissions, respectively. It is suggested for future policy implementation to support sustainable biofuel and high efficient electric-vehicles, and the deployment of coal-based fuels accompanied with low-carbon technology.     

Adaptive maximum power point tracking based on Kalman filter for hydrogen fuel cell in hybrid unmanned aerial vehicle applications

In this paper, an adaptive real-time estimation method based on Kalman filter is proposed for tracking the maximum power point (MPP) of a hydrogen fuel cell (FC) in hybrid unmanned aerial vehicle (UAV) applications. To achieve the adaptive MPP tracking (MPPT), a mathematical model for the hydrogen FC is established. Then, the recursive least square method is employed to identify the initial values of model parameters. On this basis, the MPP of the hydrogen FC under steady conditions can be derived. Furthermore, the state and observation equations based on Kalman filter are introduced to adaptively estimate the model parameters in real-time. Moreover, the real-time model parameters would be used to optimize the MPP in accordance with the operating conditions such that the adaptive MPPT can be achieved. Finally, various simulations and experiments are conducted to verify the effectiveness and accuracy of the adaptive MPPT for the hydrogen FC in hybrid UAV applications. Results show that the adaptive MPPT can not only track the MPP accurately in real-time, but also reduce the oscillation of the hydrogen FC. Compared with the MPPT methods based on perturb and observe (P&O) and particle swarm optimization (PSO), the maximum power tracking error of the adaptive MPPT can be improved by 2.83% and 1.10%, respectively.     

Influence of the electrode systems parameters on the electricity generation and the possibility of hydrogen production in a plant-microbial fuel cell

The work is devoted to the creation of plant-microbial fuel cell (PMFC). A design of а PMFC has been developed, which makes it possible to study the effect of the configuration and material of electrode systems on the values of bioelectric potentials (BEP) generated in the system of root environment-plant. The possibility of using the developed technology for measuring BEP to create long-term plant-microbial fuel cells based on the use of plants electrical activity as an electromotive force is shown. The electrodes were made of various carbon materials and stainless steel. The created experimental PMFCs are capable of generating voltages at the level of 230 mV in soil systems and 150 mV in hydroponic ones. The output power was about 50 mW/m² at a load of 10 kΩ, which did not cause significant deviations in the state of the plants. The calculated possible yield of hydrogen per m³ of the root environment was 0.2 mmol/day. Thus, PMFC can become a promising source of green energy that can be combined with significant production processes for obtaining plant products or hydrogen.     

Blending blue hydrogen with natural gas for direct consumption: Examining the effect of hydrogen concentration on transportation and well-to-combustion greenhouse gas emissions

Jurisdictions are looking into mixing hydrogen into the natural gas (NG) system to reduce greenhouse gas (GHG) emissions. Earlier studies have focused on well-to-wheel analysis of H₂ fuel cell vehicles, using high-level estimates for transportation-based emissions. There is limited research on transportation emissions of hythane, a blend of H₂ and NG used for combustion. An in-depth analysis of the pipeline transportation system was performed for hythane and includes sensitivity and uncertainty analyses. When hythane with 15% H₂ is used, transportation GHG emissions (gCO2eq/GJ) increase by 8%, combustion GHG emissions (gCO2eq/GJ) decrease by 5%, and pipeline energy capacity (GJ/hr) decreases by 11% for 50–100 million m³/d pipelines. Well-to-combustion (WTC) emissions increase by 2.0% without CCS, stay the same with a 41% CCS rate, decrease by 2.8% for the 100% CCS scenario, and decrease by 3.6% in the optimal CO₂-free scenario. While hythane contains 15% H₂ by volume only 5% of the gas’ energy comes from H₂, limiting its GHG benefit.     

Analyzing potential lead markets for hydrogen fuel cell vehicles in Europe: Expert views and spatial perspective

The paper presents spatially explicit results for 27² countries of European Union indicating the potential lead markets for hydrogen fuel cell vehicles in 2030 and 2050. The assessment combined an expert elicitation survey results and a decision-making rule applied on a regional level using region specific characteristics. It has been shown that in 2030 the EU15 countries have a higher hydrogen FCV lead market score than EU12, with the difference of the lead market potential between EU15 and EU12 reduced in 2050. The results of the study can help policy makers to identify measures that could foster the deployment of hydrogen regions in specific lead markets. This is especially crucial as a large scale deployment of hydrogen vehicles and the related infrastructure needs to develop with lead markets as nuclei for further market replication and spread.     

Policy effectiveness on emissions and cost reduction for hydrogen supply chains: The case for British Columbia

Hydrogen-specific policies are required to accelerate the adoption of low-carbon hydrogen. In this study, a range of economic instruments and regulations were incorporated explicitly to optimize a hydrogen supply chain. The effectivenes of policies aiming to enhance the financial viability of low-carbon hydrogen production was quantified. A spatially explicit, multi-period cost optimization model was developed for light duty hydrogen hydrogen vehicle deployment in British Columbia under three demand scenarios. Subsidies and regulations were coupled to current provincial policies (a carbon tax and a low carbon fuel standard). The results indicated that production tax credits and electricity incentives were up to 24 times more effective in facilitating low-carbon hydrogen production compared to capital subsidies, bans on steam methane reforming or the adoption of higher carbon taxes. The strategic deployment of policies over time was found to be more effective than cumulative subsidies.