V2G | Publications

This section has articles and reports by the University of Delaware GIV group and our industrial partners, on integrating EVs with the grid, and also on EV design, use, and policy. They are divided into peer-reviewed articles, reports, and conference presentations.

Peer-reviewed articles

GIVs and Power Markets

Parsons, George R., Michael K. Hidrue, Willett Kempton and Meryl P. Gardner. 2014. “Willingness to pay for vehicle-to-grid (V2G) electric vehicles and their contract terms”. Energy Economics , 42 (2014), p313-324. Published doi: 10.1016/j.eneco.2013.12.018, may require payment. This article reports on a survey of 3,000+ respondents regarding possible V2G contracts. Findings included that drivers did not like fixed requirements like “required plug-in time per month”, even if those fixed requirements would be easy for most drivers to meet. They seemed prefer arrangements such as being paid more or less depending on the amount of time they stayed plugged in, for example.

Tomić, Jasna and Willett Kempton, 2007, “Using fleets of electric-drive vehicles for grid support” Journal of Power Sources, 168 (20), p459-468. Published doi: 10.1016/j.jpowsour.2007.03.010., may require payment. Proof with minor errors. Examines two actual electric vehicle fleets, their operating cycles, and the value of revenue from these vehicles if they were equipped for V2G power (the fleets examined were electric but not equipped for V2G). This is a realistic analysis of real fleets in use today, and gives the revenue potential in the electric markets in which they operate.

Letendre. Steven, Paul Denholm, and Peter Lilienthal, 2006.“Electric and Hybrid Vehicles: New Load or New Resource?”, Public Utilities Fortnightly, December 2006., p28-37. (This article is co-authored by employees of the U.S. Government and is not subject to copyright.) PDF of published article. Review of V2G principles and new analysis of how it affects the load curve of electric utilities, also brief analysis of how plug power capacity affects V2G revenue. Clear and readable. Sidebar interview with CEO of Tesla Motors. The subtitle, inserted by the editors of this utility industry journal, is “The industry must join a growing chorus in calling for new technology.””

Kempton, Willett and Jasna Tomić. 2005. “Vehicle to Grid Power Implementation: from stabilizing the grid to supporting large-scale renewable energy”. Journal of Power Sources, Volume 144, Issue 1, 1 June 2005, p280-294. Published doi:10.1016/j.jpowsour.2004.12.022, may require payment. Final proof. Overall size of V2G in comparison to electric generation and load, control strategies and business models for implementation, analysis of V2G as storage for large-scale renewable electricity. Appendix gives practical considerations and capacity of power connections.

Kempton, Willett and Jasna Tomić. 2005. “Vehicle to Grid Fundamentals: Calculating Capacity and Net Revenue”, Journal of Power Sources, Volume 144, Issue 1, 1 June 2005, Pages 268-279. Published doi:10.1016/j.jpowsour.2004.12.025, may require payment. Final proof. This is our best exposition of the fundamentals of both the vehicle fleet and electric markets. The basic 17 equations of V2G are derived. Correction to published version: Page 275, Table 3, line 3: should be “27.4 kWh” not “27.4 $/kWh”.

Letendre, Steven and Willett Kempton, 2002. “The V2G Concept: A New Model for Power?”, Public Utilities Fortnightly 140(4): 16-26, February 2002, may require payment. Proof. Also available in our Japanese translation. This article is our best short summary (8 pages) of the V2G concept, incorporating findings from our CARB-LADWP report (below) that show the value of ancillary services to be far higher than that of peak power. This article is written for an electric-utility audience and thus provides less explanation of power types and markets than our articles written for a transportation audience.

Kempton, Willett and Toru Kubo. 2000. “Electric-drive Vehicles for Peak Power in Japan”, Energy Policy 28(1): 9-18. Published doi:10.1016/SO301-4215(99)00078-6, may require payment. Final proof. Also available in our Japanese translation. The Kempton-Kubo analysis is for Tokyo, based on existing power rates and Japanese driving patterns.

Kempton, Willett and Steven Letendre, 1997. “Electric Vehicles as a New Source of Power for Electric Utilities”, Transportation Research 2(3): 157-175. Published doi:10.1016/S1361-9209(97)00001-1, may require payment. Proof. This is the first description of the key concepts of V2G: That the potential resource exceeds all current electric generation by many times, that the value is not in bulk power but in responding when needed, and that the driver sets limits based on driving need within which the grid operator dispatches based on time of electric system need. This first article is before we called the idea “V2G” and the analysis is based primarily on peak power, which subsequent work (above) shows to be a lower-value market for V2G power.

GIVs for Wind Integration

Pensini, Alessandro, Claus N. Rasmussen, Willett Kempton, “Economic analysis of using excess renewable electricity to displace heating fuels”. Applied Energy 131: 530-543. doi:10.1016/j.apenergy.2014.04.111. (Open Access) Update of Budischak et al also modeling high penetration renewable generation with storage. This article adds a detailed model of heat storage using excess renewable generation and meeting hourly building heat load. PDF

Budischak, Cory, DeAnna Sewell, Heather Thomson, Leon Mach, Dana E. Veron, and Willett Kempton, 2012, Cost-minimized combination of wind power, solar power, and electrochemical storage, powering the grid up to 99.9% of the time, Journal of Power Sources, 225(2013), 60-74. Published doi: 10.1016/j.jpowsour.2012.09.954, open access. A one-page follow-up corrects two errors in the published article, doi: 10.1016/j.jpowsour.2013.01.046. Our PDF, contains the correction page. Comparison of GIV with other storage mediums for large-scale integration of renewable generation. GIV is the least expensive storage tested. At very high renewables penetration, all vehicles would be used.

Kempton, Willett and Amardeep Dhanju, 2006, “Electric Vehicles with V2G: Storage for Large-Scale Wind Power”. Windtech International 2 (2), pp 18-21, March 2006. A brief technical introduction to V2G as storage for wind power. Analyzes the duration of low-wind events as a measure of storage needs, and compares national-level potential V2G power with average load in 11 countries. This article appeared in the March 2006 issue of Windtech International and is displayed with permission. Copyright 2006 by Siteur Publications.

EV Use, Policy and Market

Kempton, W.; Pearre, N.S.; Guensler, R.; Elango, V.V. Influence of Battery Energy, Charging Power, and Charging Locations upon EVs’ Ability to Meet Trip Needs. Energies 2023, 16, 2104. Published DOI: https://doi.org/10.3390/en16052104 (Open Access).  Using driving data from a sample of gasoline passenger vehicles, a trip inventory of U.S. vehicle travel requirements was created along with a set of modeled EVs to measure and track how well each EV meets all U.S. driving requirements. PDF available.

Sovacool, Benjamin K., Lance Noel, John Axsen, and Willett Kempton, 2018. The neglected social dimensions to a vehicle-to-grid (V2G) transition: a critical and systematic review. Environmental Research Letters 13 (2018) 013001. Published DOI: 10.1088/1748-9326/aa9c6d (Open Access)

Kempton, Willett, “Electric vehicles: Driving range“, Nature Energy, News & Views, August 2016. DOI: 10.1038/NENERGY.2016.131 (may require payment), or here for author’s draft with markup. Also see news article at http://www.eco-business.com/news/anxiety-about-electric-cars-misplaced-says-study/ .

Kempton, Willett, Yannick Perez, Marc Petit, “ ‪Public Policy for Electric Vehicles and for Vehicle to GridPower‪ ”, Revue d’économie industrielle 4/2014 (No 148) , p. 263-290. URL: www.cairn.info/revue-d-economie-industrielle-2014-4-page-263.htm. Comparison of EV policies and V2G policies across multiple countries.

Noel, Lance and Regina McCormack, 2014. A cost benefit analysis of a V2G-capable electric school bus compared to a traditional diesel school bus. Applied Energy, 126: 246-265. Published doi: 10.1016/j.a[emergy.2014.04.009. As accepted copy. A comparison of total cost of ownership for a conventional school bus, versus an electric bus with v2g capabilities, and selling v2g services to the grid operator.

Pearre, Nathaniel S., Willett Kempton, Randall L. Guensler, and Vetri V. Elango, Electric vehicles: How much range is required for a day’s driving? Transport.Res.Part C (2011), doi:10.1016/j.trc.2010.12.010, may require payment. Proof, may contain typos. Driving data from 400 gasoline vehicles over a year, used to determine the distribution of daily range needed.

Hidrue, Michael K., George R. Parsons, Willett Kempton, and Meryl P. Gardner, Willingness to pay for electric vehicles and their attributes. Resource Energy Econ. (2011), doi: 10.1016/j.reseneeco.2011.02.002, may require payment. Proof, may contain typos. National survey of car buyers used to determine willingness to pay for EVs, as well as individual attributes such as longer rages, faster charging, faster acceleration, and lower pollution. This article was a top download for 2012 and 2013; get a free download through October 2013.

EV and GIV Technology

Mironenko, O.; Ejzak, G.; Kempton, W., “Integrated Electric Vehicle Shunt Current Sensing System for Concurrent Revenue Metering and Detection of DC Injection.” Energies 2021, 14, 1193. DOI: 10.3390/en14041193 (open access). PDF available.

Mironenko, Olga and Willett Kempton, 2020, “Comparing Devices for Concurrent Measurement of AC current and DC Injection During Electric Vehicle Charging” World Electric Vehicle Journal, Vol 11, Article# 57. doi:10.3390/wevj11030057 (open access). PDF available.

Nakano, Hikari, Ikumi Nawata, Shinkichi Inagaki, Akihito Kawashima, Tatsuya Suzuki, Akira Ito, and Willett Kempton, 2020, “Aggregation of V2H Systems to Participate in Regulation Market” Accepted for publication in IEEE Transactions on Automation Science and Engineering, May 2020. DOI: 10.1109/TASE.2020.3001060  [Open access preprint under: Creative Commons Attribution 4.0]

Apostolaki-Iosifidou, Elpiniki, Paul Codani, and Willett Kempton, “Measurement of Power Loss During Electric Vehicle Charging and Discharging,” Energy, 15 May, 2017, Volume 127, pages 730-742, DOI: 10.1016/j.energy.2017.03.015 , open access, creative commons license. Electric vehicle loss analyzed as a factor of state of charge and charging rate.

Houser, R., Kempton, W., McGee, R., Kiamilev, F. et al., “EV Fingerprinting,” SAE Technical Paper 2017-01-1700, 2017, DOI: 10.4271/2017-01-1700, may require payment. Proof available.

Shinzaki, S., Sadano, H., Maruyama, Y., and Kempton, W., “Deployment of Vehicle-to-Grid Technology and Related Issues,” SAE Technical Paper 2015-01-0306, 2015, doi:10.4271/2015-01-0306. Discussion of vehicle-to-grid technology to enable vehicles to contribute to stabilizing the power grid by utilizing on-board batteries as a distributed energy resource as well as an energy storage for propulsion.

Vandael, Stijn, Sachin Kamboj, Tom Holvoet, Geert Deconinck, Willett Kempton, “A comparison of two GIV mechanisms for providing ancillary services at the University of Delaware.” Proceedings of the 4th IEEE International Conference on Smart Grid Communications (SmartGridComm 2013), Vancouver, 21-24 October 2013. Pre-conference PDF. Analysis of dispatch algorithms for potentially very large numbers of EVs. Comparison of more computing decentralized to EV agents, with dispatch using a centralized algorithm in the aggregator.

Kempton, Willett, Francesco Marra, Peter Bach Anderson and Rodrigo Garcia-Valle, 2013 “Business Models and Control and Management Architectures for EV Electrical Grid integration,” accepted, IEEE Innovative Smart Grid Technologies Europe. Pre-publication version. Chapter 4 of Electric Vehicle Integration Into Modern Power Networks edited by Rodrigo Garcia-Valle and Joao A. Pecas Lopes (published by Springer Science + Business Media), pp. 87-105. Copyright 2013, IEEE. Doi: 10.1007/978-1-4614-0134-6_4. Functional comparison of liquid fuels versus electricity, comparison of functions and standards for charging stations, and review of three projects that integrate EVs into the electric grid.

Reports and theses

Johansen, Joachim Skov, 2013, “Fast-Charging Electric Vehicles using AC “, Master’s Thesis, September 2013, Danish Technical University, DTU-Electro. Or click here for a copy as of Sept 2013. A high quality, extensive analysis of electric vehicle charging and drive systems, including designs to charging integrated with the drive train.

Kempton, Willett, Victor Udo, Ken Huber, Kevin Komara, Steven Letendre, Scott Baker, Doug Brunner, & Nathaniel Pearre, 2008, “A Test of Vehicle-to-Grid (V2G) for Energy Storage and Frequency Regulation in the PJM System”. This report documents a practical demonstration of a Grid Integrated Vehicle providing real-time frequency regulation from a single electric car.  At the University of Delaware, on October 18, 2007, a team of engineers and officials from UD, Pepco Holdings Inc (PHI), and PJM Interconnection successfully interconnected an AC Propulsion “eBox” to the PJM grid using a direct AGC signal from the PJM control center.  The vehicle was dispatched in real time as a regulation resource, like traditional generators. This report covers the engineering, market and experimental results of this proof of concept demonstration and study.  (UD’s later developments use an “aggregator” to communicate with PJM, rather than PJM communicating to individual cars, that is not covered in this earlier report.)

Udo, Victor, 2008, “Proven at PJM:Vehicle to Grid (V2G) and Power System/Transportation Synergies,”, Energy Pulse, November 17, 2008. This report explains the overall approach of using electric vehicles to support the power system. Also, reports on the first successful dispatch of an electric vehicle from a real-time ISO signal, with a photo of the event.

Gage, Thomas B., 2003. “Final Report Development and Evaluation of a Plug-in HEV with Vehicle-to-Grid Power Flow”, Report, AC Propulsion, December 2003. This report describes a tri-fuel vehicle which was designed, built, and tested, under CARB Grant Number ICAT 01-2. The prototype vehicle is refueled and run on electricity or natural gas, or gasoline, using a series hybrid. From the abstract: The project vehicle provides 35 miles of battery-only range with highway performance capability so operation on grid electricity can eliminate operating emissions and one or more cold engine starts per day. The project vehicle can re-charge its traction battery from the grid in less than one hour. The hybrid power unit in the project vehicle can sustain battery charge at highway speeds providing long distance travel unconstrained by battery range. The hybrid power unit in the project vehicle can also generate electricity while the vehicle is parked. In this stationary mode, the hybrid power unit can operate on gasoline stored on the vehicle or on low-pressure natural gas piped to the vehicle from the gas main. While parked, the power generated can be exported as alternating current electricity either to the grid or to stand-alone loads. Interactions between the vehicle and the grid, including power export, can be controlled from remote locations via wireless internet connection. These capabilities are demonstrated in stationary testing and 6000 miles of on-road use.

Brooks, Alec, 2002. “Vehicle-to-Grid Demonstration Project: Grid Regulation Ancillary Service with a Battery Electric Vehicle”, Report, AC Propulsion, December 2002. Sponsored by CARB. In addition to the test results, this report has a thorough analysis of regulation services and how V2G can provide them. From the abstract: A test vehicle was fitted with a bidirectional grid power interface and wireless internet connectivity, allowing power flow to or from the vehicle to be dispatched remotely. Power dispatch commands were sent wirelessly to the vehicle at 4-second intervals, and the vehicle response was monitored and recorded. Results showed that wireless data transmission times were within ISO system requirements, and that the energy throughput through the battery due to regulation is similar to that of typical daily driving. The value created by the service exceeds the battery wear out costs under most operating assumptions.

Kempton, Willett, Jasna Tomić, Steven Letendre, Alex Brooks & Timothy Lipman. 2001. Vehicle-to-Grid Power: Battery, Hybrid, and Fuel Cell Vehicles as Resources for Distributed Electric Power in California. UCD-ITS-RR-01-03. For an executive summary, click on HTML or PDF, or click on the title above for the full report. This CARB/LADWP-sponsored report is specific to California, yet it has comprehensive analysis on V2G, some not in subsequent publications. This was the first full coverage of all three vehicle types–battery, fuel cell and hybrid vehicles, across four power markets–baseload, peak, spinning reserves, and regulation services. The approach and formulae developed and explained here are the basis for our subsequent analysis. (Although our equation notation was rationalized and standardized in our 2005 and later publications. Very brief summary of economic results: Battery vehicles (also called “electric vehicles” or EVs) with telematics and power electronics designed to allow V2G could earn $2,000 – $3,000 per year by selling a form of power called “regulation services.” Fuel cell and hybrid vehicles could earn $1,500 – $2,500 per year by selling electricity as “spinning reserves.” We found that V2G is economically valuable in the CalISO market for these forms of electric power that go on briefly when needed. Vehicles do not appear to be economically competitive for “baseload power,” that is, constant power generation, which has lower blue per kWh and more drain on the battery, hydrogen, or fuel tank.

Early conference presentations and unrefereed papers

These papers are of interest as a snapshot of where the technology and policy was circa 2000.

Presentations from The Seattle Electric Vehicle to Grid Forum (2005). Press release and schedule of speakers and topics.

The two papers below are from a symposium organized by Alec Brooks, “Vehicle to Grid: A new Vision for Electric Transportation,” at the EVAA Electric Transportation Industry Conference (Sacramento, Dec. 2001).

David Hawkins, from the California Independent System Operator, discusses V2G as a resource for grid regulation in California. He explains what the ISO does, and compares V2G with traditional sources of regulation–generators running at partial speed. He also describes the characteristics of wind generation, of which 2-3 GW is planned to be added in California, and why V2G is an ideal complement for it. Click to see the slides in PDF: David Hawkins, 2001, “Vehicle to Grid–A Control Area Operators Perspective”

These slides give an overview of V2G for regulation, then give specifications for already built by AC Propulsion that are capable of doing real-time grid regulation. It also describes two V2G demonstration projects they are carrying out, the “EV Grid Regulation Demonstration Project” and the “Grid Connected Hybrid Vehicle Project.” Click for PDF of slides: Alec Brooks, 2001, “Electric Drive Vehicles: A Huge New Distributed Energy Resource”

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