arnis wrote:V2G is absolute nonsense.
No, it is actually a great idea.
arnis wrote:It requires massive investment and pays very little back.
Today. If we are smart, that will change.
arnis wrote:What makes sense is smart delay system: charging stops on demand for a second/minute/hour. Requires almost no investment and is efficient.
Agreed this is the most appropriate first step.
arnis wrote:V2G is a lose-lose cycle.
Agreed that storing energy should be avoided, when possible.
arnis wrote:Energy lost due to charging.
Yes, approximately 1%.
arnis wrote:Energy lost due to discharging.
Another approximately 1%.
arnis wrote:Energy lost due to conversation from grid AC to battery DC and back again.
Approximately 1% each way if done well
arnis wrote:Energy lost due to line-losses.
Nonsense, since the vehicle is *much* closer to the load than the power plant. This is actually an important benefit of B2G technology.
arnis wrote:Grid-2-grid cycle total efficiency catastrophic.
95% efficiency is "catastrophic"? No, that kind of efficiency is what enables this type of technology to allow us to move into the future.
arnis wrote:I don't understand why educated engineers (there are no at Nissan as we all know) don't stop this nonsense.
So you are saying that the engineers at Nissan that developed the BEV which is still the top-selling EV in the world six-and-a-half years after it was introduced into the market
are uneducated? What a ridiculous statement. I have met quite a few of the engineers who designed the LEAF and I can tell you that they are extremely talented at their jobs. Frankly, I think an apology is appropriate.
arnis wrote:Most likely same reason why hydrogen was hot thing for years.
I don't recall hydrogen ever being "hot" beyond in the minds of some who don't (or won't?) see the obvious problems with that approach.
arnis wrote:PS! after all those losses car must be charged AGAIN.
This is where the approach taken to V2G becomes important. Obviously, you need to keep enough charge in your vehicle to get to your destination (plus a healthy margin). While this is only possible with a small subset of the BEVs in use today, it is likely to be commonplace in the near future.
But the other part of the equation is when the BEV is charged. As more and more PV generators are added to the grid, it will become more-and-more important to provide storage so that PV generation does not have to be curtailed. Since vehicle batteries NEED to be stored AND since Li-ion storage batteries are the most efficient form of storage around, the obvious thing to do is to charge those BEV batteries when the sun is shining.
The next issue then becomes how to prevent from running fossil-fuel-based generators when the sun does not shine and the wind does not blow. Sure, you could buy EXTRA batteries to do this, but that would mean having nearly double the amount of batteries than would otherwise be needed. We already have a desire to have lots of extra battery capacity in our cars for convenience and for longer trips. Why not use that capacity for other purposes when not needed for driving?
is to move the metering for BEV charging and discharging to the vehicle itself. This would allow for "vehicle net metering" to allow BEV owners to purchase electricity during the daytime when there is a glut of PV energy (and therefore low prices) and allow them to sell at nighttime to either offset their consumption at nighttime or to provide energy to the grid in order to reduce the electricity needed from fossil-fuel generators.
arnis wrote:And there is also a cycling degradation.
That is a real issue with *some* Li-ion batteries today. Of course, we know that this is NOT a fundamental limitation of Li-ion batteries, but rather it is an issue that will be almost completely engineered out of most future batteries. As it stands, there are already Li-ion chemistries which can withstand 12,000 FULL cycles and still retain over 80% of their original capacity
. This level of durability (and more) is coming to the vast majority of the Li-ion batteries in the future.
Simply put, Li-ion batteries are the key enabling technology not only for BEVs, but for much higher penetration levels of renewable generators on our electricity grids. The Li-ion batteries in future BEVs should have the capacity and durability to provide for a multi-purpose role.