A comprehensive optimized model for on‐board solar photovoltaic system for plug‐in electric vehicles: energy and economic impacts

Environmental concerns along with high energy demand in transportation are leading to major development in sustainable transportation technologies, not the least of which is the utilization of clean energy sources. Solar energy as an auxiliary power source of on‐board fuel has not been extensively investigated. This study focuses on the energy and economic aspects of optimizing and hybridizing, the conventional energy path of plug‐in electric vehicles (EVs) using solar energy by means of on‐board photovoltaic (PV) system as an auxiliary fuel source. This study is novel in that the authors (i) modeled the comprehensive on‐board PV system for plug‐in EV; (ii) optimized various design parameters for optimum well‐to‐tank efficiency (solar energy to battery bank); (iii) estimated hybrid solar plug‐in EVs energy generation and consumption, as well as pure solar PV daily range extender; and (iv) estimated the economic return of investment (ROI) value of adding on‐board PVs for plug‐in EVs under different cost scenarios, driving locations, and vehicle specifications. For this study, two months in two US cities were selected, which represent the extremities in terms of available solar energy; June in Phoenix, Arizona and December in Boston, Massachusetts to represent the driving conditions in all the US states at any time followed by assessment of the results worldwide. The results show that, by adding on‐board PVs to cover less than 50% (around 3.2 m²) of the projected horizontal surface area of a typical passenger EV, the daily driving range could be extended from 3.0 miles to 62.5 miles by solar energy based on vehicle specifications, locations, season, and total time the EV remains at Sun. In addition, the ROI of adding PVs on‐board with EV over its lifetime shows only small negative values (larger than ?45%) when the price of electricity remains below Environmental concerns along with high energy demand in transportation are leading to major development in sustainable transportation technologies, not the least of which is the utilization of clean energy sources. Solar energy as an auxiliary power source of on‐board fuel has not been extensively investigated. This study focuses on the energy and economic aspects of optimizing and hybridizing, the conventional energy path of plug‐in electric vehicles (EVs) using solar energy by means of on‐board photovoltaic (PV) system as an auxiliary fuel source. This study is novel in that the authors (i) modeled the comprehensive on‐board PV system for plug‐in EV; (ii) optimized various design parameters for optimum well‐to‐tank efficiency (solar energy to battery bank); (iii) estimated hybrid solar plug‐in EVs energy generation and consumption, as well as pure solar PV daily range extender; and (iv) estimated the economic return of investment (ROI) value of adding on‐board PVs for plug‐in EVs under different cost scenarios, driving locations, and vehicle specifications. For this study, two months in two US cities were selected, which represent the extremities in terms of available solar energy; June in Phoenix, Arizona and December in Boston, Massachusetts to represent the driving conditions in all the US states at any time followed by assessment of the results worldwide. The results show that, by adding on‐board PVs to cover less than 50% (around 3.2 m²) of the projected horizontal surface area of a typical passenger EV, the daily driving range could be extended from 3.0 miles to 62.5 miles by solar energy based on vehicle specifications, locations, season, and total time the EV remains at Sun. In addition, the ROI of adding PVs on‐board with EV over its lifetime shows only small negative values (larger than ?45%) when the price of electricity remains below $0.18/kWh and the vehicle is driven in low‐solar energy area (e.g. Massachusetts in the US and majority of Europe countries). The ROI is more than 148% if the vehicle is driven in high‐solar energy area (e.g. Arizona in the US, most Africa countries, Middle East, and Mumbai in India), even if the electricity price remains low. For high electricity price regions ($0.35/kWh), the ROI is positive and high under all driving scenarios (above 560%). Also, the reported system has the potential to reduce electricity consumption from grid by around 4.5 to 21.0 MWh per EV lifetime. A sensitivity analysis has been carried out, in order to study the impacts of the car parked in the shade on the results. Copyright © 2016 John Wiley & Sons, Ltd.     

Performance optimization of hybrid hydrogen fuel cell-electric vehicles in real driving cycles

In this research study, a fuel cell-electric hybrid car is studied. This car includes an electric motor that is connected to a fuel cell and a complex which includes a battery pack and an Ultracapacitor. The assessment of this hybrid vehicle is conducted by using various driving cycles such as FTP-75 driving cycle, NEDC driving cycle and SFTP-SC03 driving cycle. Battery state of charge (SoC) and hydrogen fuel consumption are the effective parameters influencing the vehicle performance. For analysing the performance of this vehicle, an innovative computational model is considered. In this innovative computational model, an accurate control strategy is considered in order to control the power demand, staying the battery packs and the Ultracapacitor state of charge in a limited domain. Results show that in NEDC driving cycle, by means of using Ultracapacitor in this model, 3.3% reduction in fuel consumption and 20.2% decrease in the difference between initial and final State of Charge (SoC) in battery pack can be achieved. In addition, a robust regenerative braking control strategy is used in order to recover some parts of the wasted energy in braking driving modes.     

Hybrid,plug-in hybrid,or electric—What do car buyers want?

We use a survey to compare consumers’ stated interest in conventional gasoline (CV), hybrid (HEV), plug-in hybrid (PHEV) and pure electric vehicles (EV) of varying designs and prices. Data are from 508 households representing new vehicle buyers in San Diego County, California in 2011. The mixed-mode survey collected information about access to residential recharge infrastructure, three days of driving patterns, and desired vehicle designs and motivations via design games. Across the higher and lower price scenarios, a majority of consumers designed and selected some form of PHEV for their next new vehicle, smaller numbers designed an HEV or a conventional vehicle, and only a few percent designed an EV. Of those who did not design an EV, the most frequent concerns with EVs were limited range, charger availability, and higher vehicle purchase prices. Positive interest in HEVs, PHEVs and EVs was associated with vehicle images of intelligence, responsibility, and support of the environment and nation (United States). The distribution of vehicle designs suggests that cheaper, smaller battery PHEVs may achieve more short-term market success than larger battery PHEVs or EV. New car buyers’ present interests align with less expensive first steps in a transition to electric-drive vehicles.     

Efficient model predictive control for real-time energy optimization of battery-supercapacitors in electric vehicles

Integration of batteries and supercapacitors (B-SCs) is widely used to improve performance of electric vehicles (EVs). In this article, we consider the energy optimization problem of B-SCs in EVs and propose an efficient model predictive control (MPC) algorithm for real-time energy optimization of the hybrid energy storage system of EVs. Back propagation neural network is firstly adopted to learn the velocity prediction ability over a finite horizon by standard driving cycles. Then real-time energy optimization of B-SCs in EVs is formulated as the finite horizon optimal control problem by taking into account the constraints, the cost function on battery current, and the predicted velocity of the EV. Moreover, to lessen the computational burden of online solving the problem, the Pontryagin's Minimum Principle is used in a fashion of receding horizon. Compared with traditional nonlinear MPC, simulation results verify the effectiveness of the proposed MPC algorithm for real-time energy optimization of B-SCs in EVs.     

Total cost of ownership of electric vehicles compared to conventional vehicles: A probabilistic analysis and projection across market segments

While electric vehicles (EV) can perform better than conventional vehicles from an environmental standpoint, consumers perceive them to be more expensive due to their higher capital cost. Recent studies calculated the total cost of ownership (TCO) to evaluate the complete cost for the consumer, focusing on individual vehicle classes, powertrain technologies, or use cases. To provide a comprehensive overview, we built a probabilistic simulation model broad enough to capture most of a national market. Our findings indicate that the comparative cost efficiency of EV increases with the consumer's driving distance and is higher for small than for large vehicles. However, our sensitivity analysis shows that the exact TCO is subject to the development of vehicle and operating costs and thus uncertain. Although the TCO of electric vehicles may become close to or even lower than that of conventional vehicles by 2025, our findings add evidence to past studies showing that the TCO does not reflect how consumers make their purchase decision today. Based on these findings, we discuss policy measures that educate consumers about the TCO of different vehicle types based on their individual preferences. In addition, measures improving the charging infrastructure and further decreasing battery cost are discussed.     

Assessing the operation and different refuelling cost scenarios of a fuel cell electric bicycle under low-pressure hydrogen storage

The transition to low- or zero-emission vehicles in the transportation sector is a challenging task toward meeting the greenhouse gas emission targets set by the majority of countries. One way of achieving this goal is to utilise hydrogen gas via fuel cell electric vehicles. This paper investigates the operation, driving range and refuelling process of a fuel cell electric bicycle. The methodology applied includes an estimation of the bike's range under different routes and riders, the riders' opinions and a financial evaluation of the hydrogen fuel cost compared to other urban vehicle alternatives. The results showed a minimum median range-to-energy consumption ratio of 20.5 km/kWh, while the maximum hydrogen cost was found to reach 0.025 €/km when refuelling the hydrogen bicycle in an autonomous hydrogen station. The outcome of this study indicates that the introduction of light-duty hydrogen vehicles in urban transportation may adequately meet the average daily driving distance of city residents.     

Energy performance and well-to-wheel analysis of different powertrain solutions for freight transportation

In this paper we compare energy performance and environmental impact of four nominal weight classes of commercial vehicles with different powertrain solutions: conventional diesel internal combustion engine (ICE), Plug-In Electric Vehicle (PHEV), Battery Electric Vehicle (BEV) and Plug-In Fuel Cell Vehicle (PFCV). First, the sizing of the various powertrain components is performed adopting a simplified calculation based on a rule-based model. Then, the energy performances are evaluated through simulation over different driving cycles carried out with a self-developed Matlab/Simulink® simulator tool based on a forward-looking approach, that implements a control strategy that targets the instant velocity specified by the driving cycle. We show that when the optimal control strategy based on the Pontryagin's Minimum Principle is adopted, the fuel consumption significantly reduces with respect to the simplified rule-based control strategy approach. Finally, the overall specific energy consumption and the corresponding greenhouse gases (GHG) emissions are evaluated by means of a well-to-wheel analysis, considering various possible scenarios, covering the main traditional and low emission solutions for production, transportation and distribution of diesel, electricity and hydrogen. As expected, the highest GHG emissions are obtained in case of fossil origin of the energy carrier, with maximum value of 270 gCO₂/km/kg in case of 3.5 ton truck with traditional diesel ICE, due to the low powertrain efficiency compared to the other considered solutions. Moreover, both the specific primary energy consumption and GHG emissions proportionally reduce with tonnage, as a consequence of the progressive reduction of the fraction of the powertrain weight with respect to the total vehicle mass.     

A grand design of future electric vehicle to reduce urban warming and CO2 emissions in urban area

In the present study, the new environmentally-compatible vehicle was designed to mitigate urban warming, air pollution and carbon dioxide (CO₂) emissions in the urban area. Principal specifications for its optimal design will be clarified and it will be shown that urban environment is improved with dissemination of such vehicles. First, we evaluate optimal specifications of the new conceptual hybrid EV (Electric Vehicle) equipped with the flywheel and photovoltaic (PV) cell and also report the results of the driving simulation of the proposed vehicles. The energy density of the flywheel made of Carbon Fiber Reinforced Plastics (CFRP) is three times higher than Pb battery, which has been used for the EVs. The most noticeable feature of the flywheel is that it has very high charging rate. By employing the flywheel and PV cell as energy regeneration, the electric power consumption rate of the vehicle can be 188 km/l in the community-driving schedule, and over 50 km/l in the long-driving schedules (the electric power consumption rate is converted to the fuel consumption rate of gasoline). Furthermore, three-dimensional computer simulation of urban atmosphere is conducted and it is shown that the dissemination of the proposed vehicle reduce the concentration of CO₂ in the urban area and mitigate urban warming.     

Experimental assessment of energy-management strategies in fuel-cell propulsion systems

The limitations of electric vehicles equipped with electrochemical batteries justify strong research interest for new solutions, based on hydrogen fuel-cell technology that are able to improve vehicle range, and reduce battery recharging time, while maintaining the crucial advantages of high efficiency and local zero emissions. The best working of a fuel-cell propulsion system, in terms of optimum efficiency and performance, is based on specific strategies of energy management, that are designed to regulate the power flows between the fuel cells, electric energy-storage systems and electric drive during the vehicle mission. An experimental study has been carried out on a small-size electric propulsion system based on a 2.5-kW proton exchange membrane fuel cell stack and a 2.5-kW electric drive. The fuel-cell system has been integrated into a powertrain comprising a dc–dc converter, a lead–acid battery pack, and brushless electric drive. The experiments are conducted on a test bench that is able to simulate the vehicle behaviour and road characteristics on specific driving cycles. The experimental runs are carried out on the European R40 driving cycle using different energy-management procedures and both dynamic performance and energy consumption are evaluated.     

A comparative review on power conversion topologies and energy storage system for electric vehicles

Fossil fuel depletion and its adverse impact on global warming is a major driving force for a recent upsurge in the development of hybrid electric vehicles technologies. This paper is a conglomeration of the recent literature in the usages of an energy storage system and power conversion topologies in electric vehicles (EVs). An EV requires sources that have high power and energy density to decrease the charging time. Commonly used energy storage devices in EVs are fuel cells, batteries, ultracapacitors, flywheel, and photovoltaic arrays. The power output from energy storage sources is conditioned to match load characteristics with the source for maximum power delivery. A DC-DC converter topology performs this task by way of transforming voltage under the condition of power invariance. In addition, power electronics is also required to power DC/AC motors efficiently with precise control as these motors provide tractive efforts and acts as prime movers. This paper therefore brings out a critical review of the literature on EV's power conversion topologies and energy storage systems with challenges, opportunities and future directions by systematic classification of EVs and energy storage.     

Willingness to pay and preferences for alternative incentives to EV purchase subsidies: An empirical study in China

The transport sector's promotion of electric vehicles (EVs) is an important tool in reducing greenhouse gas emissions. The high monetary subsidies widely used to promote EV diffusion in many countries are not sustainable in the long term. Therefore, effective alternative incentives are needed as subsidies are gradually phased out. In this paper, consumers' willingness to pay (WTP) for alternative incentives is studied based on a questionnaire survey. Using a discrete choice experiment, 1719 Chinese consumer questionnaires were collected. Consumers' WTP for nine alternative policies was calculated by applying the multinomial logit model and mixed logit model, and the mixed logit model is used as the main model of this study because of its better statistical performance. Finally, the relationship between the respondent heterogeneity and policy preferences was studied. The results show that alternative incentives can fill the gap produced by subsidy reductions. EV privileges like no restrictions on driving and purchases, which have the lowest implementation cost, are suitable for first- and second- tier cities. For second-tier cities, construction of more charging stations is the most appropriate choice. The heterogeneous features of the respondents, including cities of residence, type of vehicle owned, recognition of the environmental benefits of EVs, gender, and whether the family has children, had a significant impact on policy preferences.     

A comprehensive review on theoretical framework‐based electric vehicle consumer adoption research

Green vehicles, such as electric vehicles (EVs), are getting noteworthy popularity among consumers worldwide. The purpose of this paper is to establish EVs as a feasible long‐term solution for the future of technology in the vehicle industry, which can decrease the current dependency on fossil fuels and also decrease greenhouse gas (GHG) emissions. As a part of long‐term benefits, the adoption of EVs gives environmentally friendly innovation to society. Despite positive environmental implications, the total number of EVs in usage is still inadequate. One of the major causes of this insubstantial adoption of EVs is largely dependent on the perceptions of consumers regarding EVs. However, this particular research study offers an inclusive outline on the existing hurdles for consumer adoption of EVs as well as a framework of the theoretical standpoints that were developed for the adoption behaviour, in addition to considering consumer intentions in the direction of EVs. In this particular study, the researcher found that the literature regarding EV adoption tried to address only the diffusion method of EVs. Whereas this study highlights consumer innovations, which provides a wide insight on consumer emotions to overlook the major aspect in consumer EVs' adoption research. The theme of this particular literature can be implemented in order to better understand the consumers' emotions and behaviour towards the adoption of EVs. The scholars further stated that there is a possible cause for more recent developments within the technological adoption part that can assist to be a standard for upcoming developments. For the last few years, knowledge regarding the problems surrounding the adoption and diffusion of EVs has gained less attention. This study expands this line of research by focusing on making a chance for developing the theoretical frameworks in terms of adding emotions in a psychological perspective where consumer behaviour and ethics are considered. Copyright © 2016 John Wiley & Sons, Ltd.     

Transition strategy of the transportation energy and powertrain in China

The problems of the transportation energy and environment are the major challenges faced globally in the 21st century and are especially serious for China. The future 20 years is the strategic opportunity period of the transition of the transportation energy and powertrain system for China. The greatest characteristics of hydrogen economy lie in its diversity of the primary energy source, the unification of energy carrier and the greening of energy transformation. Development of hydrogen energy transportation powertrain system is suitable for China from the views of the situation of Chinese resources and energy sources, the urban and rural layouts, the superiority of later development and the successful practices of clean cars and electric vehicle development projects. The transition of the transportation energy powertrain system includes three parts: the transition of the energy structure, the transition of the powertrain system and the transition of the fuel infrastructure. The technical pathways of energy powertrain system transition includes expending the use of gaseous fuel to prompt the multiform of the transportation energy and to prepare for the transition of the infrastructure simultaneously, developing and promoting the hybrid technology to solve the current energy and environment problems and to prepare for the transition of powertrain system, and focusing on the research and development and demonstration of fuel cell vehicles and the hydrogen energy technology to prompt the earlier formation of the market of fuel cell vehicles. The goal in the near and medium term of transition is to reduce the fuel consumption by 100 million ton in 2020 by substituting and saving, and the long-term goal is to setup the infrastructure of hydrogen and fuel cell vehicle as the main one replacing the petroleum internal combustion engine vehicle. In order to realize the strategic goals of the transition, the four-phases strategic periods and research and development activities are discussed and proposed.     

Review on non-isolated multi-input step-up converters for grid-independent hybrid electric vehicles

The increase in temperature, regulations of CO2 emissions, and the cost of conventional fuels forced the transportation industry to move towards the electrical energy sector. The increasing nature of electrification of transportation will increase the stress on the existing power system because of the charging of battery-based electric vehicles (EV). This paper briefly reviews the effect of electrification of transportation on the existing power system. The Lion's share of the EVs is battery-based, and these EVs extensively depend on Lithium. The Lithium is a non-renewable energy source just like fossil fuels, and reserves may last one day. The availability of Lithium reserves across the world and alternate for the grid-dependent EVs are illustrated in this paper. This paper also briefly discusses the fuel cell-based EVs, solar PV based EVs along with battery-based EVs and compare the battery with fuel cell.There is a significant need for research and development on grid-independent hybrid electric vehicles (GIHEV). From the last few years, the extensive part of the hybrid electric vehicles is making use of multi-input DC-DC converters to interface multiple sources to enhance the performance and reliability of the vehicle. Among different types of multi-input DC-DC converters, non-isolated multi-input DC-DC converters are best suited for low and medium power electric vehicle applications. This paper displays the synthesizing process of multi-input converters. Some of the existing efficient non-isolated multi-input high step-up DC-DC converter topologies are immensely discussed and compared. This review is intended to serve as a suitable guideline and reference for future work in the field of non-isolated multi-input high step-up DC-DC converter topologies for GIHEVs.     

电动汽车电池的充电状态和健康状况评估：关键问题和挑战

使用电动汽车（EV）进行运输被视为实现可持续发展和解决环境问题的必要组成部分。当前对环境的关注,例如化石燃料的快速消耗,空气污染的增加,能源需求的加速增长,全球变暖和气候变化,为交通运输部门的电气化铺平了道路。电动汽车可以解决上述问题。电源已成为电动汽车发展的关键,尤其是锂离子（Li-ion）电池。由于其能量密度、功率...     

Quantitative analysis of fuel-saving potential for waste heat recovery system integrated with hybrid electric vehicle

Hybrid electric vehicles (HEVs) with low fuel consumption, low emissions, and long driving range are the ideal transition models between conventional fuel vehicles and pure electric vehicles. The growing demand for increased vehicle efficiency has motivated the introduction of waste heat recovery (WHR) technology in the automotive industry, with the organic Rankine cycle (ORC) as the most promising measure for recycling waste energy. Currently, only a few studies have been conducted to couple HEV and WHR systems. These studies have mainly focused on the hybrid powertrain control strategy, but lack quantitative methods to comprehensively analyze the fuel-saving potential due to the WHR system. In this study, an HEV-WHR integrated system that includes a mechanism-based dynamic model of ORC and a hybrid diesel-electric truck model is established. Further, a quantitative evaluation method that simultaneously considers the negative integrated effects (increased vehicle weight and increased exhaust back pressure) and the positive impact values of the engine, motor, and WHR system on the fuel-saving potential is proposed. Finally, the influence of two environmental factors (wind speed and ambient temperature) on the fuel-saving performance is analyzed. The results reveal that under the standard highway driving cycle (HWY), the negative integrated effects reduce the ideal fuel-saving potential of the HEV-WHR system from 6.10% to 5.42%. However, the optimized performances of the engine, motor, and WHR system improve the fuel-saving rate by 0.39%, 1.81%, and 3.22%, respectively. The results also indicate that the fuel-saving potential increases from 1.62% to 8.60% with increasing wind speed and decreases from 6.70% to 4.25% with increasing ambient temperature.     

Analyzing public awareness and acceptance of alternative fuel vehicles in China: The case of EV

The aim of this paper is to analyze consumers' awareness towards electric vehicle (EV) and examine the factors that are most likely to affect consumers' choice for EV in China. A comprehensive questionnaire survey has been conducted with 299 respondents from various driving schools in Nanjing. Three binary logistic regression models were used to determine the factors that contribute to consumers' acceptance of EVs, their purchase time and their purchase price. The results suggest that:     

Does energy storage provide a profitable second life for electric vehicle batteries?

Electric vehicles (EVs) are increasingly being seen as part of the solution to address environmental issues related to fossil fuel use. At the forefront of the EV revolution is China where EV sales have witnessed a dramatic increase. A direct consequence of a larger number of EVs on the roads is the growth in retired batteries once they have reached the end of their useful life inside an EV. This increasing stockpile of retired batteries raises the question of whether and how they can be disposed of, reused, repurposed or recycled. In this paper we investigate under which circumstances the use of second life batteries in stationary energy storage systems in China can be profitable using an operational optimization model. Our results show that an EV battery could achieve a second life value of 785 CNY/kWh (116 USD/kWh) if it is purchased with a remaining capacity of 80% and being abandoned when the capacity reaches 50%. Profit margins for energy storage firms are reduced if the acquisition costs of second life batteries are considered. The price range for second life batteries is assumed to range between a lower limit of the ‘Willing to sell’ price from the perspective of EV owners and an upper limit being the ‘Market evaluation’ price based on battery condition and the market price for a new EV battery. It's found that when the remaining capacity in retirement is below 87%, the application of retired battery energy storage can achieve pareto improvement from the perspective of social welfare. In addition, it's estimated that the optimal remaining capacity in retirement would be 77%. Our results suggest that EV adoption rates can be improved if a second life market can be successfully established.     

Innovative design of an hydrogen powertrain via reverse engineering

In this paper the powertrain of a zero emission vehicle powered by hydrogen has been designed with an innovative approach via reverse engineering.The use of a zero environmental impact vehicles is particularly stringent in urban area where high air pollutant concentrations could be reached. In particular, in this paper, the use of fuel cell vehicles plus ultracapacitors has been considered to minimize the TTW (Tank to Wheels) global efficiency in comparison with the conventional vehicles powered by ICE.A zero emissions city-car is designed by optimization of the components (in particular the energy storage) in order to minimize both its weight and its bulk with particular reference to the functions (passenger vehicles, minibus, freight distribution), the areas where the vehicle is driven (characteristic drive cycles, traffic) and the users (different driving style). In particular the design discussed in this paper was carried out through a process of reverse engineering. The energy needs, in fact, were calculated starting from real drive cycles obtained during an on-board data acquisition campaign carried out in Rome urban area.In this paper the powertrain is designed starting from the acquisition of real drive cycles obtained during acquisitions campaign in an urban area. The data collected by the on-board acquisitions systems has been used to evaluate the power required by the wheels as a function of time in a generic urban drive cycle and the energy needs of an urban vehicle. Thus, the analysis performed takes into account not only global energy consumption, but also the power needs that are affected by both the congested traffic conditions and the driving style.     

Micro-hybrid electric vehicle application of valve-regulated lead–acid batteries in absorbent glass mat technology: Testing a partial-state-of-charge operation strategy

The BMW Group has launched two micro-hybrid functions in high volume models in order to contribute to reduction of fuel consumption in modern passenger cars. Both the brake energy regeneration (BER) and the auto-start-stop function (ASSF) are based on the conventional 14 V vehicle electrical system and current series components with only little modifications. An intelligent control algorithm of the alternator enables recuperative charging in braking and coasting phases, known as BER. By switching off the internal combustion engine at a vehicle standstill the idling fuel consumption is effectively reduced by ASSF. By reason of economy and package a lead–acid battery is used as electrochemical energy storage device.