v2g state of the art technology

Titolo presentazionesottotitolo

Milano, XX mese 20XX

Vehicle-to-Grid future technology assesmentReview of V2G technology prospetive and potential interaction with RES-E volatile production as well as integration in the ancillary service market for dispatching service

Marco Tognoli 842586, Dept. Of Energy Engineering

Vehicle to grid or dual energy flow EV process is a concept recently introduced and currently under testing. This concept involves strictly three vehicle powertrain technologies:□ Plug-in hybrid car□ Fuel-cell hydrogen car□ Electric-vehicle powered by Li-ion batteries (EV)

Due to technological flexibility of EV we will always refer to V2G technique as strictly related to EVs.Following a 2001 US research, cars are daily driven for nearly 63 min/day. This means that a car stay parked for most of the time in a year. The V2G approach helps into exploiting this wasted time for delivering a grid service. The conflict in place regards the functioning of this service which is technically different from the EV construction architecture.

Vehicle-to-Grid technology


Purpose of the project:□ Integrate the existing smart grid□ Create a new service□ Improve QoS especially at DSO side□ Prosumers’ smartening□ Displacement of traditional balancing reserves with beneficial

economic effect on the electric bill



Basic functioning operations:□ As the EV is physically connected to a

charging station the company responsible of the station establish an identification and control processes on the system installed on board by a powerline medium communication.

□ The pole station inform the company central system (Station Company Operator) in real time of the operation performing at the station itself (Grid-to-Vehicle or V2G) communicating the power allocated and the battery residual capacity.

□ The central system at SCO, as central post communication with all the charging stations, create a virtual unique balancing reserve or “virtual storage network” that can directly participate by placing bids in the Ancillary Service Market.



The EV’s owner requires special needs separated from network situation. The owner may requires a charging operation or more strictly a fast charging mode.Consequently the system is arranged in three main working possibilities:□ Not in place, no control on the charging process. This possibility is not going to be in place

on the long run due to the expected EV share in the transportation field, this is going to cause unpredictable congestion situations at specific hours (this is not a pragmatic solution).

□ Smart charging or demand dispatch, the vehicle-to-grid architecture is in place but not under use. The SCO collects congestion situation of the network close to the charging station and sent dispatch information to the station requesting rump-down of power allocated for charging process. The command could even request the abort of charging process, charging is postponed in time.

□ Ancillary grid service, online negotiation between car and SCO is established so that reverse power flow is allowed. The EV’s owner receive income from frequency regulation service and this could represent a faster way to return on EV initial investment.



□ The device needs to rely on the daily car schedule and particularly on some special events. Apparatus must be very smart so that they need to integrate a “machine learning” algorithm.

□ This schedule is integrated, and improved in time, inside the vehicle so that the charging station download these data every time the car is grid connected.

□ Some basic charging choices can be directly done at the charging pole side or by a remote platform like a web page or a simple mobile application so that the owner is informed in real time and he/she is allowed to receive notifications at status change.

□ To terminate the grid connection the owner have to perform a remote billing operation. To interrupt the energy flow the system requires an authorization by means of an univocal card which communicate with the charging station by means of an RFID or NFC communication. The TSO or DSO provide the monetary value of service exploited and finally the system aggregator perform the billing process which will be globally accounted at the end of the control period.

Terms of innovation


Terms of innovation


The leading goal of the V2G integration is the regulation service provided.□ This statement suffers from lack of actual legislation nor for complexity of its integration in

the existing network framework.□ A possibility is represented by merging together the SCO or system aggregator with the

existing DSO or TSO management. Even though currently the engagement rules for ancillary service participation allows connections just on the TSO side.

□ A reform on ancillary service requirements is expected in the future and it will introduce a more strict partnership and open access policy between TSO and DSO.

□ As a consequence other services away from V2G could enter the regulation services like: home storage systems, RES-E programmable/non-programmable or high efficiency CHP plant, demand response (user’s self curtailment).

A new service on the market


□ V2G can answer to system regulation that occurs at every hours of the day. The dispatch order of rump up power injection or proceed with charging operation to reduce over frequency can be made with little time delay. The system inertia of a V2G device is negligible and just limited by the power electronic.

□ It is observed that dispatched amount does not last for very long time, in general it involves just some minutes and much less than contracted amount.

□ This consideration result in quite constant battery residual capacity with very little discharge-charge. This result is in favour of battery wear which does not entail deep battery discharge and recharge cycle.

□ The V2G process involves much more deep power injected or exploited rather than an energy intensive mechanism.

□ EVs are mostly connected to LV lines and at some public charging station at MV lines. Their contribute is an homogeneously dispersed type which could provide beneficial effects on constrained DSO network portions.



□ Even though, a reserve connected to high power line (i.e. MV) is much more valuable than a standard LV single phase connection.

□ Managing such service with a battery EV represent some sort of constrain. Every dispatch order must match the power capacity of the line and the charge level of the battery. The operator can no longer ask for down regulation beyond battery full charge as well as no further injection into the grid beyond battery dead level.

□ Two hypothesis can be performed on the contract type accounted for the service:1. Long term contract, a minimum number of hours per day in service is the key part of the

contract. Billing process is then performed on the stipulated hours. Possible integration with capacity mechanism.

2. Join as-you-go, dynamic contract at which the TSO (or DSO) accounts for every regulating session. Constrain free solution but still much more challenging under management point.



□ Regulation service could represent a consistent voice of income and its magnitude depend linearly with: time spent to serve the system, power allowed by the charging station, smart logic control of charging/discharging device. Average income value over 10 years is 10.000$.

□ It has been demonstrated that V2G service is responsible for just 5% over battery degradation over the control period. This effect is not going to represent any issue in case of battery leasing contract which is a quite common situation.

□ Future improvements are expected, particularly regarding the Vehicle-to-home strategy to energize the household in case of local network loss of main. Improved security systems must be present to avoid any local islanding away from house grid portion in order to maintain a feasible security level.

□ V2G technology requires full-optional smart grid infrastructure particularly at LV and MV side. Moreover a widespread EVs presence over the system requires network physical improvement as contractual power of many users is going to increase and become bidirectional. This reflects also on network apparatus like power transformer and security devices.

□ The other improvement side is on interoperability issue of aggregator services and feel-like-home policies abroad. Each nation has to provide sufficient legislation and access to V2G technology even coming up with an unique and interoperable standard.



• http://www.mobilitaverde.it/wp-content/uploads/2016/05/nissan-enel.jpg• http://www.automotive-fleet.com/news/story/2016/09/commercial-vehicle-to-grid-hub-installe

d-in-denmark.aspx• http://www.nuvve.com/gtm-can-nuvve-make-v2g-work-in-the-real-world/• US Patent 8509976 B2 by Willett Kempton “Electric vehicle equipment for grid-integrated

vehicles”• “A Test of Vehicle-to-Grid (V2G) for Energy Storage and Frequency Regulation in the PJM

System” Willett Kempton, Victor Udo, Ken Huber, Kevin Komara, Steve Letendre, Scott Baker, Doug Brunner, & Nat Pearre

• https://www.youtube.com/watch?v=QqfMwEQ2pbc

Reference

http://www.mobilitaverde.it/wp-content/uploads/2016/05/nissan-enel.jpg

http://www.automotive-fleet.com/news/story/2016/09/commercial-vehicle-to-grid-hub-installed-in-denmark.aspx

http://www.automotive-fleet.com/news/story/2016/09/commercial-vehicle-to-grid-hub-installed-in-denmark.aspx

http://www.nuvve.com/gtm-can-nuvve-make-v2g-work-in-the-real-world/

https://www.youtube.com/watch?v=QqfMwEQ2pbc