Abstract

In literature, several mechanisms are proposed to prevent Plug-in Electric Vehicles (PEVs) from overloading the distribution grid. However, it is unclear how such technical mechanisms influence the market level control strategies of a PEV aggregator. Moreover, the presence of multiple aggregators in the same distribution grid further complicates the problem. Often, grid congestion management mechanisms are proposed to solve the potential interference between the technical and market objectives. Such methods come at the expense of additional complexity and costs, which is not beneficial for the large scale application of demand response. In our work, we investigate this problem by combining a simple low level voltage droop controller with an event driven control strategy for the coordination of charging PEVs. The approach is evaluated in different distribution grid settings, using two different market objectives for the aggregator. Document type: Part of book or chapter of book

Abstract

Sweden has the goal of reaching a fossil independent transportation sector by 2030. Two ways to reach the goal is to increase the use of electric vehicles or produce more biofuels. Both alternatives could be powered by forest residue, which is an underutilized resource in the country. Electricity could be produced in a biomass fired Combined Heat and Power (CHP) plant, and biofuel could be produced in a biorefinery through gasification of biomass and Fischer-Tropsch process. When located in Stockholm County, both system can also distribute heat to the district heating system. It is however important to use the biomass in an energy-efficient way. The scope of this work has been to analyze the efficiency together with environmental and economic aspects of the two systems.  To assess the efficiency and environmental impact of the two systems a forest to wheel study was made of the systems where the product was studied from harvesting of forest residue to driving the vehicle. The studied functional units were: kilometers driven by vehicle, kWh of district heating, CO2-equivalents of greenhouse gases and MWh of forest residue. The system using CHP technology and electric vehicles outperformed the biorefinery system on the two first functional units. Using the same amount of forest residue more than twice as much district heating and almost twice as many driven kilometers were produced in this system. The study also showed that both systems avoids significant greenhouse gas emissions and can be part of the solution to decrease emissions from road transportation.  The profitability of investing in a CHP plant or a biorefinery was calculated through the net present value method. It showed that the expected energy prices are too low for the investments to be profitable. The CHP plant investment has a net present value of -1.6 billion SEK and the biorefinery investment has a net present value of -4.6 billion SEK. Furthermore, the biorefinery investment entails higher risk due to the high investment cost and uncommercialized technology. Both systems face barriers for implementation, these barriers have been studied qualitatively.  Sverige har som mål att skapa en fossiloberoende fordonsflotta till år 2030. Två vägar som pekats ut för att nå målet är att öka användningen av eldrivna fordon eller att producera mer biobränsle. Båda alternativen kan drivas av skogsavfall, en råvara som det finns gott om i Sverige. Elektricitet kan produceras av skogsavfallet i ett kraftvärmeverk, och biobränsle i ett bioraffinaderi genom användning av förgasning och Fischer-Tropschmetoden. I Stockholms län skulle båda systemen dessutom kunna producera värme till Stockholms fjärrvärmesystem. Det är dock viktigt att använda skogsavfallet på ett resurseffektivt sätt. Därför undersöker detta arbete effektiviteten av de två olika systemen tillsammans med en analys av växthusgasutsläpp och ekonomiska förutsättningar.  För att kunna utvärdera effektiviteten och klimatpåverkan av de två olika systemen utfördes en ”skog-till-hjul”-analys där produkten undersöktes från ursprunget, till drivandet av ett fordon. För att utföra studien definierades fyra funktionella enheter. De funktionella enheterna var: körsträcka med bil mätt i kilometer, kWh fjärrvärmeproduktion, CO2 ekvivalenter av växthusgasutsläpp och MWh skogsavfall. Studien visade att systemet där skogsavfallet används i ett kraftvärmeverk för att producera elektricitet och ladda elbilar hade bättre resultat i de två första funktionella enheterna. Systemet producerade nästan dubbelt så lång körsträcka och mer än dubbelt så mycket fjärrvärme som systemet där skogsavfallet används i ett bioraffinaderi och biobränslet används i dieselbilar. Studien visade även att båda system kan bidra till att sänka växthusgasutsläppen från transportsektorn.  Lönsamheten att investera i ett kraftvärmeverk eller bioraffinaderi beräknades med nuvärdesmetoden. Studien visade att de förväntade framtida energipriserna är för låga för att investeringarna ska bli lönsamma. Kraftvärmeanläggningen hade ett nuvärde på -1.6 miljarder kronor, och bioraffinaderiet ett nuvärde på -4.6 miljarder kronor. Dessutom ansågs investeringen i ett bioraffinaderi vara en hög risk på grund av den höga investeringskostnaden och att tekniken idag inte är kommersialiserad. Det finns även en rad andra barriär för att genomföra de två olika systemen, dessa barriärer har studerats kvalitativt i arbetet. 

Abstract

Electric vehicles have existed for over 100 years as a disruptive innovation. Even though they have always been easier to use, quieter and cleaner, gasoline cars have beaten it in price, range and faster fueling. As gasoline cars have been the technological standard for the past 150 years there has been no motivation by car manufacturers to advance electric vehicles. By producing electric vehicles Tesla Motors has appropriately become the first successful startup car manufacturer in over 100 years. This research studies the systemic innovating of electric vehicles by Tesla Motors. Disruptive innovation is widely researched and often connected to electric vehicles. However systemic innovation has been rarely researched and none has shown that electric vehicles can be seen as one since they require significant adjustments to the business system they are embedded in to succeed as a disruptive innovation. Therefore I suggest that in certain instances a disruptive innovation requires systemic innovating. In the context of electric vehicles systemic innovating can be done on the disruptive technology level of batteries, on the finished product level of the car and on the external level of services such as charging stations. Tesla Motors is doubling the world’s lithium-ion battery production to enable inexpensive electric vehicles. It has produced an electric vehicle platform architecture that has advantages not seen in gasoline cars. It is also creating the standard for charging stations and its battery swapping technology is providing almost instant charging. As Tesla Motors is solving the challenges of high price, low range and slow charging, at the same time it is capitalizing and building on the unique advantages electric vehicles have always had and ultimately proving electric vehicles superiority. This is largely the result of the visionary of Tesla Motor’s CEO Elon Musk who is aiming to transform the world into sustainable energy and transportation through solar panels and batteries.

Abstract

The Swedish transportation sector needs to undergo major changes in order to achieve the established goals for climate and environment. The largest change is the replacement of fossil-fuelled vehicles to vehicles propelled by renewable energy sources, such as biofuels and electricity. To account for an increase in local electric power consumption, the electric power infrastructure of Sweden needs to adapt through expansion and reconstruction of the electric power grid. However, changes in infrastructure are usually expensive. It is therefore suitable to also examine alternative solutions, which could potentially be more cost efficient. One of these solutions are vehicle-to-grid (V2G), where electric vehicles acts as local electric power control and provides auxiliary services to the electric power grid. This thesis is a case study of a part of a low-voltage electric power grid on Gotland, with the goal of analysing the potential of V2G in the investigated area. The study focused on utilizing V2G for balancing electric power consumption and generation, and for adjusting voltage levels. Simulations of the area were executed in PSS®E for three different cases; one high-load case, low-load case and average-load case. It was found that by utilizing V2G a ramp up of electric power during mornings was delayed by approximately one hour, making the electric power grid potentially more compatible with photovoltaics (PV). However, the overall effects from V2G was fairly low. This outcome can partly be explained by the assumptions made in the report, and also due to some odd behaviour of the system model. 

Abstract

How many Teslas will it take to crash the Los Angeles, California, grid? This thesis conducts a thought experiment to explore whether rapid adoption of electric vehicles (EVs) in Los Angeles will reduce the reliability of electric power in the Los Angeles Department of Water and Power (LADWP) service territory. Federal and state regulations are encouraging the shift to electric transportation in support of policy priorities that include reducing greenhouse gas emissions and reducing dependence on foreign energy sources. However, high market penetration by EVs will change the patterns of electricity use, especially in urban areas. Under some scenarios, EVs could pose a risk to the reliability and resilience of the electric grid serving these areas. To explore this issue, I developed a model that projects the impact of EVs on the peak power load in Los Angeles in 2030 under different scenarios of EV market penetration and constraints on demand for vehicle charging (e.g., time-of-day pricing). I found that even with moderate EV penetration, if vehicle charging is unconstrained, the load placed on the LADWP grid will exceed the established reserve margin in 2030. Only by adopting some form of incentives for EV drivers to shift their power demands from the normal end-of-day charging routine will the LADWP be able to maintain the reliability and resilience of the power grid. http://archive.org/details/hittingtheaccele1094563490 Civilian, Department of Homeland Security Approved for public release; distribution is unlimited.

Abstract

Deploying an adequate electric vehicle (EV) charging infrastructure to support the increasing EV market is one of the major strategic goals of the U.S. government. This requires a well-designed EV charging network. The distribution and capability of the existing charging networks in terms of EV population, location, charging rate, and time of charging in San Diego is examined. A mathematical model to calculate the demand number of public Level 2 chargers universally applicable is developed. The study showed that although San Diego has sufficient chargers to accommodate the existing EV’s charging demand, the current public charging distribution network is neither well designed nor effectively used. To eliminate the waste resulting from the inefficiently designed charging infrastructure and maximize the usage rate of each charger, it is recommended that the designed optimal model to be utilized and the charging location priority be implemented to improve the availability and accessibility of charging network in the City of San Diego. Introduction: The purpose of this study is to identify current problems with the existing electric vehicle public charging stations and come up with solutions to improve the availability and accessibility of public charging stations in the City of San Diego. The objective of this research project is also to develop a mathematical model to predict the demand of EV chargers in any city including in the City of San Diego. Methods: A mix of quantitative and qualitative research methods are used to analyze the problem. The first phase of this project is to determine the study area by identifying the existing problems and issues from existing sources, and formulating hypothesis. Results: The distribution and capability of the existing charging networks in terms of EV population, location, charging rate, and time of charging in San Diego was examined. A mathematical model to calculate the demand number of public Level 2 chargers for the City of San Diego and for each zip code was developed. Among 361 tested public Level 2 chargers distributed in 34 communities, 66 chargers located at 37 charging stations distributed in 22 communities were found to be nonoperational or damaged but still operational. They accounted for 18% of the total number of tested EV charging stations and 12.7% of the total public Level 2 in San Diego. The model tested using data from San Francisco Bay Area, and Los Angeles County matched well to the predictions. Conclusions: The conclusion is that although San Diego has sufficient chargers to accommodate the existing EV’s charging demand, the current public charging distribution network is neither well designed nor effectively used. To eliminate the waste resulting from the inefficiently designed charging infrastructure and maximize the usage rate of each charger, it is recommended that the designed optimal model to be utilized and the charging location priority be implemented to improve the availability and accessibility of charging network in the City of San Diego. This model is easily applicable in the European environment since all the five significant independent variables (B/E - Battery capacity to EV Range Ratio, D-Driver Traveling Distance, β - Ratio of EV driver charges away from home, PrefL2 - percentage that EV driver prefers to charge on Level 2 stations, and TL2- duration of public Level 2 chargers’ work per day) are easy to obtain. Hence this proposed model has universal applicability. Document type: Article

Abstract

The share of renewable energy sources (RES)’ production in energy mixes, especially the ones of PV panels and wind farms, has been continuously increasing during the last few years. Similarly, a strong development of battery electric vehicles (EV) is expected within the next years. However, these two new innovations could trigger security issues on electrical grids, in particular local congestions and voltage deviations from the required standards. One way to mitigate these problems could be to combine the charging periods of the EVs with the local RES production. This paper aims at analysing the possibility to implement this kind of smart charging strategy in France by 2020, taking into account the wide diversity of local energy mixes in France and their seasonal dependencies. First, the authors identify four different energy mixes representative of most of the local French mixes, each one related to a region in France. Then, we model the charging load curves of the EVs at the substation level for the same regions. We deduce the “green charging ratio” (GCR) without any charging management strategy. The same ratio is then computed assuming that an Energy Management System (EMS), which goal is to maximize this ratio, controls the EV charging patterns. The results are provided for each region and seasons. They show a wide diversity of green charging ratio achievable: in very windy regions, the GCR without any EMS is already rather high on the contrary, in sunny regions, the GCR is much improved with the implementation of the EMS. In such regions, the GCR can also be enhanced with the penetration of charging stations at working places. Document type: Article

Abstract

SUMMARY This article investigates charging strategies for plug-in hybrid electric vehicles (PHEV) as part of the energy system. The objective was to increase the combined all-electric mileage (total distance driven using only the traction batteries in each PHEV) when the total charging power at each workplace is subject to severe limitations imposed by the energy system. In order to allocate this power optimally, different input variables, such as state-of-charge, battery size, travel distance, and parking time, were considered. The required vehicle mobility was generated using a novel agent-based model that describes the spatiotemporal movement of individual PHEVs. The results show that, in the case of Helsinki (Finland), smart control strategies could lead to an increase of over 5% in the all-electric mileage compared to a no-control strategy. With a high prediction error, or with a particularly small or large battery, the benefits of smart charging fade off. Smart PHEV charging strategies, when applied to the optimal allocation of limited charging power between the cars of a vehicle fleet, seem counterintuitively to provide only a modest increase in the all-electric mileage. A simple charging strategy based on allocating power to PHEVs equally could thus perform sufficiently well. This finding may be important for the future planning of smart grids as limiting the charging power of larger PHEV fleets will sometimes be necessary as a result of grid restrictions. Copyright © 2013 John Wiley & Sons, Ltd.

Abstract

© The Institution of Engineering and Technology. One of the main problems in electric vehicles is the volume of their electrical systems because their bulky components carry additional mass and high cost to the total system. On this topic, interleaving-phases and magnetic coupling techniques have been reported as effective methods for increasing the power density of the DC-DC converters that work between the storage unit and the motor inverter. In that sense, a volume assessment of these topologies would provide a better understanding of the problems to be faced when an electric power train is designed. In this paper, a volume modelling methodology is introduced with the purpose of comparing four different DC-DC converters: Single-Phase Boost, Two-Phase Interleaved with non-coupled inductors, Loosely Coupled Inductor (LCI), and Integrated Winding Coupled Inductor (IWCI). The analysis considers the volume of magnetic components, power devices (conventional and next-generation), cooling devices and capacitors. The methodology can be used as a part of an optimization procedure to minimize the volume of DC-DC converters. Conclusively, LCI and IWCI were found effective to miniaturize power converters with a power density of 8.4 W/cc and 9.66 W/cc, respectively. Moreover, a maximum efficiency of 98.04% and 97.61% was obtained for a 1kW LCI and IWCI prototypes, respectively. ispartof: IET POWER ELECTRONICS vol:10 issue:14 pages:2010-2020 status: published