Environment & Energy
Related: About this forumVehicle to Grid Demonstration Project
Vehicle to Grid Demonstration Project
DE-FC26-08NT01905 University of Delaware Newark, Delaware 19716
Willett Kempton, College Earth, Ocean, and Environment 302-831-0049, willett@udel.edu
Keith Decker, Li Liao Dept Computer & Information Sciences
Meryl Gardner, Michael Hidrue, Fouad Kamilev, Sachin Kamboj, Jon Lilley, Rodney McGee, George Parsons, Nat Pearre, Keith Trnka.
October 1, 2008 to December 31, 2010 7 May 2011
Executive summary
This report summarizes the activities and accomplishments of a two-year DOE-funded project on Grid-Integrated Vehicles (GIV) with vehicle to grid power (V2G). The project included several research and development components: an analysis of US driving patterns; an analysis of the market for EVs and V2G-capable EVs; development and testing of GIV components (in-car and in-EVSE); interconnect law and policy; and development and filing of patents. In addition, development activities included GIV manufacturing and licensing of technologies developed under this grant. Also, five vehicles were built and deployed, four for the fleet of the State of Delaware, plus one for the University of Delaware fleet.
Fundamental technical concept
In the United States, passenger vehicles are, on average, driven about 1 hour a day the remaining 23 hours they are parked, most often either at home or at work. The average distance driven each day is around 30 miles. However, a typical electric vehicle (EV) has a range of about 100 miles, meaning that on most days, there would be around 70 miles worth of battery capacity left in the vehicle. Further, to perform adequately at highway speeds, electric vehicles require a drive train output of 100 kW. Thus, the vehicle electronics are already sized for power output at levels above standard AC vehicle connections. Thus, most vehicles are parked most of the time, and existing vehicle systems can draw or provide substantial power available to and from the grid.
A grid integrated vehicle (GIV) is an EV with built-in communication and control software that allows it to interact with the electric grid. A GIV with vehicle to grid capability (V2G) can additionally provide power from its battery, through its existing drive electronics, back to the grid. That is, GIV refers to control by the grid operator (of charging and/or discharging), V2G refers to the additional ability to discharge to the grid. An aggregated fleet of GIVs has the potential therefore to store a large amount of energy. If the entire US light vehicle fleet of 200 million vehicles were V2G-capable (at 15 kW per vehicle), then the total amount of power that could be provided would equal 3,000 GW. This amount is three times the current US generation capacity (1,000 GW) and six times the countrys load (450 GW). This project developed, built, and tested vehicles with both GIV and V2G capability, as the latter is more challenging for both technical, standards, and OEM comfort reasons. The systems and regulatory systems tested here can be used for either GIV with charging capability only, or for GIV with V2G.
GIVs provide storage at the low-voltage end of the distribution system. A 15 kW grid connection and a per vehicle storage capacity of 30 kWh means that GIVs are only capable of short discharges/charges and are thus better suited to capacity markets not providing baseload power. However, given that GIV is a secondary use of customer equipment (the primary use of course being transportation) means that a GIV system would have very low capital costs essentially just the on-board GIV control and communication equipment, currently around $400. The operating cost for such a system is the payment to the drivers as an incentive to remain plugged in, plus compensation for any additional battery wear. We estimate that payment for incremental equipment and compensation for wear (not including driver incentive nor management and operations), for an EV with a 15 kW connection and a 30 kWh storage capability, the capacity cost would be $27/kW and the storage cost $13/kWh. Both figures are at least an order of magnitude less than purpose-built battery storage systems. The capacity cost (per kW) is two orders of magnitude less than any known utility-scale energy storage system (including CAES and pumped hydro).
Download 21 page report: http://www.osti.gov/bridge/servlets/purl/1053603/1053603.pdf
OKIsItJustMe
(19,933 posts)(The 98 page generalized, entry level summary by the Idaho National Laboratory I cited yesterday is from 2012, but oh well )
The fact of the matter is, V2G can mean much more than the EV scenario. (When I first read about Kempton & V2G several years ago, it was in regards to hybrid-electrics.)
This is from a 2006 presentation of his:
http://www.arb.ca.gov/msprog/zevprog/2006symposium/presentations/tomic.pdf
kristopher
(29,798 posts)OK:
Let's repeat that - "V2G could have a significantly detrimental effect on battery lifespan"
In response I asked you three questions:
Battery life is largely determined by full discharge cycles.
How does V2G use a battery to augment the performance of the grid?
As planned for initial deployment, does it result in full discharge cycles?
Let me highlight a key point in the question: "As planned for initial deployment..."
You haven't answered any of those three questions. Instead you through up a very general intro level blurb about what V2G is and claim "The definition of V2G is somewhat nebulous".
As you can see from the Kempton paper, it isn't nebulous at all.
Your obvious intent is to confirm your claim that "V2G could have a significantly detrimental effect on battery lifespan"
To that end you glom onto any reference to battery degradation - WITHOUT REGARD to the questions I asked or any curiosity as to how the answers to those questions might inform the discussion.
Don't you think that is an extremely curious tack of a person who purports to orient his thinking around the scientific method?
Now, do you know the answers to those questions? If so, how can you support the claim that "V2G could have a significantly detrimental effect on battery lifespan"?
If you don't know the answer, why not act like an adult and say so.
OKIsItJustMe
(19,933 posts)Q: Do you actually know how V2G uses a battery?
A: Yes. (It potentially uses it in many ways. In a most basic sense, it reverses the normal flow, from battery to grid. Perhaps for a few seconds, perhaps for a few minutes, perhaps for much longer.)
Battery life is largely determined by full discharge cycles.
True. Is that a question?
Partial cycles dont have the same effect as full cycles.
Q: How does V2G use a battery to augment the performance of the grid?
A: (Potentially) in many ways. It might offset momentary fluctuations, or it might be used to supplement power generation. (Perhaps you should read the excerpt I posted yesterday.)
This is from one of Kemptons earliest papers on the topic:
http://www.udel.edu/V2G/docs/Kempton-Letendre-97.pdf
Now, tell me, if the maintained level of charge is as little as what is needed to travel 1 mile, would that count as full discharge in your book?
Q: As planned for initial deployment, does it result in full discharge cycles?
OK, so how about a more recent paper?
http://www.udel.edu/V2G/resources/test-v2g-in-pjm-jan09.pdf
As was illustrated in Figures 8 and 9, the unpredictable nature of regulation may at times fully charge or discharge the vehicles battery.
(You may want to read the rest of the paper.)
kristopher
(29,798 posts)...as you seem dedicated to accomplishing that entirely on your own initiative.
Let's recap.
You claim significant damage to batteries results from participating in V2G transfers.
You have no evidence of that at all. The closest you've come is an out of context cherry picked sentence from the 2008 Kempton paper that is talking about problems that can happen IF no safeguards are used to prevent them from happening. Full quote:
Perhaps you should look up the words 'dishonest' and 'deception'.
You demonstrated conclusively that your earlier False Claim of Damage was based on either lack of knowledge or the desire to misinform. Given your long and unwavering track record promoting hydrogen fuel cells and disparaging battery electric vehicles, I'm betting it is the latter.
PS: As for the 1997 proposed vehicle control interface panel having a reading of 1mile - I presume you missed the part where the bidirectional system was also envisioned as a way to provide emergency back up power to a home?
PPS: The international standard to beat for EV batteries is 10,000 charge discharge cycles with more than 85% retention of original charge levels.
10000 / 365 = 27.4 years of daily full cycle discharges.
That's where the edge is now and what we are seeking to improve upon.
PPPS: Due to limited numbers of vehicles, initial use of V2G will focus on reactive power support, which is accomplished with very, very small amounts of power being withdrawn and replaced. The idea that this is going to produce any undue wear and tear on batteries is absurd. As higher penetration of EVs is accomplished, the role will change and other business models will become practical.
http://www.udel.edu/V2G/resources/Chapter-4_09-05-12_clean.pdf
PPPPS: For those who want to read more, Kempton's list of V2G publications can be accessed here: http://www.udel.edu/V2G/ArticlesandPapers.html
OKIsItJustMe
(19,933 posts)Does a small charge/discharge cycle have no effect on a battery?
What about thousands of them?
kristopher
(29,798 posts)The range of short cycles that a battery can handle is usually somewhere between 400,000 to 1,000,000.
OKIsItJustMe
(19,933 posts)- Every presentation of V2G I have seen (including the OP) has stated that the car owner will be paid to cover battery wear. Try a quick search: [br]https://duckduckgo.com/?q=%22battery+wear%22+V2G[BR]You suggest there is no significant battery wear. So, which is it?
- Every presentation of V2G I have seen has mentioned the consumers ability to set parameters for battery usage.[br]http://www.udel.edu/V2G/QandA.html
Q: If electric vehicles are range-limited already, why should I allow someone to discharge my battery?
A: GIVs will have a controller that allow the vehicle owner to limit the amount of battery discharge to ensure they can meet the range needed for their next driving event.
If no significant level of discharge will take place, why bother with this controller? - How small a discharge cycle can a battery handle 400,000 to 1,000,000 of? How many of these are likely to occur in a day?[br]A simplistic rule of thumb Ive seen in multiple places is that (for example) four 25% discharge cycles = 1 full discharge cycle[br]While reality is always more complex than a rule of thumb, each charge/discharge cycle does inflict battery wear. A battery used for V2G will experience significant degradation, just as a battery which is always charged using a fast charger will experience significant degradation. (Can you tolerate significant degradation? Probably, after all, you will be paid for it, but you should not ignore it.)
kristopher
(29,798 posts)As in, taking the entirety of my comments into account. You do yourself no good by ignoring the way different V2G markets are present as the number of V2G Evs grows and as the quality of batteries matures. All you are doing is demonstrating the same willingness to misrepresent the evidence as we saw above.
You have found nothing to substantiate your FUDistic claim. Nothing.
The fact that they consider how to protect the system from problems isn't support for your claim.
Likewise, the fact that they need to address concerns raised by people like you spreading FUD isn't support for your claim.
OKIsItJustMe
(19,933 posts)Batteries wear with use. The designers of V2G understand this.
You pretend it is not a factor worthy of consideration.
kristopher
(29,798 posts)No one said batteries do not "wear with use".
Someone (YOU) did say "V2G could have a significantly detrimental effect on battery lifespan" .
You knew better when you wrote it and that constitutes deliberately spreading FUD.