V2G

[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]

Study Finds PHEV Li-ion Iron Phosphate Cells Show Little Capacity Fade Under Combined Driving and V2G Usage; Economic Model Suggests Incentives Will Be Required for Vehicle Owners to Participate in V2G

October 20, 2009

[This is a revision of an earlier post, which had been pulled due to the status of the referenced papers as working papers. Both have now been revised and accepted by the Journal of Power Sources and are in press.]

Degradation as a function of (a) capacity (Ah) processed by cell or (b) energy (Wh) at different DoD. Different DoD did not have a large impact on capacity fade. Source: Peterson et al. (CEIC-09-02) Click to enlarge.

Researchers at Carnegie Mellon Electricity Industry Center have concluded that a PHEV pack comprising lithium iron phosphate cells would incur little capacity loss from combining vehicle-to-grid (V2G) activities with regular driving. Statistical analyses indicated that rapid battery cycling incurred when driving degraded the cells more than slower, vehicle-to-grid galvanostatic cycling.

Scott Peterson, Jay Apt, and Jay Whitacre also found that the percent capacity lost in the cells (they used A123Systems 26650 M1 cells, which are used in the Hymotion PHEV conversion packs) per normalized Wh or Ah processed is quite low even based on just use in a dynamic driving cycle—more than 95% of the original cell capacity remained after thousands of driving days worth of use. However, in a companion paper assessing the economics of V2G for consumers, they also concluded that the maximum annual profit for a PHEV owner to engage in V2G (~$10-$120) would likely prove insufficient to encourage use of the battery pack for grid electricity storage and later off-vehicle use.

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Siemens Highlights Prototypes of New Drive Systems for Electric Cars

March 13, 2009

The powertrain components for the eRUF. Source; Siemens CT. Click to enlarge.

Siemens Corporate Technology, Siemens’ research organization, supplied the drive systems for the prototypes of two electric cars shown at the Geneva Motor Show. For each of two automotive firms—the Swiss concept car manufacturer Rinspeed and the German company RUF Automobile GmbH—the Siemens research team developed an integrated system consisting of a motor/generator, power electronics and an interface with a battery connection.

This research is taking place within the framework of the exploration by Siemens Corporate Technology of the opportunities and challenges associated with a comprehensive concept of electro-mobility and its value-added chain. Topics under investigation include, among others, energy generation and distribution; traffic and energy management; smart metering; power electronics; software and sensor technology; electric drive train systems; and the recovery and storage of energy.

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NREL Study Concludes That PHEVs and V2G Can Reduce NOx Emissions from Power Generation

January 24, 2009

Total annual per-vehicle tailpipe, refinery, and generation emissions of pollutants with different-sized PHEV fleets, with V2G services provided by the PHEV fleet (CO2-e is in tonnes, SO2 and NOx are in kg). Credit: ACS. Click to enlarge.

A new study has concluded that in addition to reducing emissions from the transportation sector, plug-in hybrid electric vehicles may further increase the efficiency of power generation plants and reduce overall emissions by providing two vehicle-to-grid services: energy storage and ancillary services. A paper on the analysis was published online 22 January in the ACS journal Environmental Science & Technology.

Ramteen Sioshansi (currently at Ohio State University) and Paul Denholm at the US Department of Energy’s National Renewable Energy Laboratory (NREL) found that by changing generator dispatch, a PHEV fleet of up to 15% of light-duty vehicles can decrease net generator NO_x emissions during the ozone season, despite the additional charging load. By adding vehicle-to-grid (V2G) services, such as spinning reserves and energy storage, CO₂, SO₂ and NO_x emissions can be reduced even further.

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City Of Newark, Delaware First US Electric Utility to Approve Use of V2G

January 18, 2009

The City of Newark, Delaware has become the first electric utility in the United States to approve the use of an electric vehicle to store and provide power for the local electric grid.

University of Delaware (UD) researchers led by Associate Professor Willett Kempton developed the Vehicle-to-Grid (V2G) concept in collaboration with a consortium (MAGIC, Mid-Atlantic Grid Interactive Cars Consortium) of industry partners over the past decade to establish the communications protocol between the vehicle and the grid operator. (Earlier post.) Industry partners in the consortium include Delmarva Power and its parent company Pepco Holdings Inc; PJM, the regional grid operator; California-based electric vehicle manufacturer AC Propulsion; and others.

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AC Propulsion System Powers the MINI E

November 24, 2008

AC Propulsion Drive System for MINI E. Click to enlarge.

AC Propulsion is supplying both the electric propulsion and the battery technology for the MINI E electric vehicle introduced at the 2008 Los Angeles Auto Show by BMW Group. (Earlier post.) AC Propulsion has already delivered more than 500 drive systems to the BMW Group factory in Munich for MINI E production.

The MINI E features a 150 kW (204 hp) electric motor powered by a 35 kWh lithium-ion battery pack (approximately 28 kWh usable), with a single-stage helical gearbox transferring power to the front wheels. The electric drive train produces a peak torque of 220 Nm (162 lb-ft), with 0 to 100 kph acceleration in 8.5 seconds. Top speed is electronically limited to 152 kph (95 mph).

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Two Southeast Utilities Partner on Plug-In Hybrid Smart Charging Trial

November 03, 2008

Advanced Energy, in partnership with utilities Duke Energy and Progress Energy, will initiate a smart charging trial of plug-in hybrid electric vehicles (PHEVs). Twelve converted Toyota Priuses will be equipped with charging management technology from Seattle-based V2Green (earlier post) and deployed in North Carolina and Florida.

Advanced Energy will lead the design and implementation of the charging management scenarios to be explored in the trial. The trial will assess the potential of plug-in vehicles to positively impact electric grid operations, maximize use of clean energy and demonstrate that PHEVs are a viable alternative to today’s cars.

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