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Saturday, March 10, 2018

Breaking the Cycle of Anti-nuclear Indoctrination--the "Electric vehicles will store excess electricity from wind and solar" argument

My old Leaf, my new Bolt, and a Tesla Model S

From a comment field under a GTM article:

I just bought my second generation electric car because my old car battery has finally reached the point that I can't reliably do my commute without hitting a fast charger. That would have happened sooner had the utility been sharing it.
Anonymous anti-nuclear indoctrination victim:
Actually, no:

"Intelligent use of vehicle to grid (V2G) technology can improve the battery life of electric vehicles according to a new study from the University of Warwick, potentially disproving a key criticism levelled at the technology."

Please try to keep up.

This is a typical case of a tale growing larger with each retelling. He/she was quoting from an article in Clean Energy News titled V2G found to improve the lifetime of electric vehicle batteries about a study published in Science Direct Energy titled On the possibility of extending the lifetime of lithium-ion batteries through optimal V2G facilitated by an integrated vehicle and smart-grid system.

He/she never read past the click-bait headline and certainly didn't read the study. It's no secret that one can optimize battery life by not letting it sit idle for long periods at high states of charge and by avoiding certain temperature regimes when charging or discharging it. But there are operational trade-offs associated with doing that.

When I first bought my Nissan Leaf (6.5 years ago) I charged it only to 80% to extend its battery life. However, after a few incidents where I wish I had that extra 20%, I stopped doing it. And as battery capacity fades over the years, the last thing you want to do is further reduce your range by reducing the charge on your car.

Another option (other than not fully charging your car) would be to bleed electricity from your battery to lower the state of charge when it's going to sit idle for most of a day by turning on the heater (and hope you won't regret doing that when you don't have enough range one day). But you paid to charge the battery and dumping its energy to the air to extend its life would be a losing proposition. Ideally, you would instead use that electricity to save money by displacing grid electricity.

Using the above ideas, the study concluded that it would not be feasible to use electric cars for energy arbitrage at the household level. However, it hypothesized that it might be feasible for large commercial buildings to use employees' electric cars in a "smart car parking lot" to buy and sell energy on the grid (sell when demand and price is high, buy when they are lower).

Criteria needed to match this study's results:

The odds of meeting all of those requirements are zero today and will very likely remain zero into the foreseeable future and even if they could be met, only a third of the cars would be able to participate on any given day, and only some commercial buildings would participate. You can't predict the future. There is no way your car can know what route you will take after work and therefore can't consistently predict how much charge must be protected from grid use.

In a nutshell, your employer gets a lower electric bill by tapping employee car batteries in the parking lot. There's no mention of the employer reimbursing the employees who paid for that electricity when charging at home.

Although it didn't say why, the study suggested that for all of this to work, the cars would somehow have to be trickle charge overnight at home from "relatively cheap" pumped hydro or compressed air storage (neither of which are scalable). See Figure below.

Illustration of the V2G topology proposed in this work. Renewable energy is stored in a cheap, efficient storage device and trickle charged to the vehicle overnight. The clean energy is then sold to the commercial building during peak times. The balance of energy required to power commercial vehicles, homes and in some instances the car comes from the grid.

The only potential benefit I can see to the car owner (among the potential problems) is the off-chance for a higher resale value many years away assuming they can convince someone that their car is worth more after convincing them that the battery is a little less worn out. Good luck with all of that.

And finally, this study was based on a few dozen battery cells in a lab. The odds are low that those results and especially the potential benefits hypothesized will translate to the real world.

To ice this cake, from an editor at the CleanTechnica tabloid:
Tesla CTO JB Straubel is one of the most respected battery experts on the planet, and a few weeks ago we shared an interesting video of him talking about batteries in which he touched on the topic late in the 36-minute video.

V2G & smart charging: Notably, the summary is that JB makes the case that it doesn’t make economic sense for EVs to send electricity back to the grid

I’m definitely inclined to accept JB’s analysis of the tech, so V2G [electric car to grid] and reusing EV batteries for grid storage are now dead-in-the-water ideas to me.

Wind and solar will play major roles in the grid. They just can't do it all.

This article will be added to the list found at Breaking the Anti-nuclear Indoctrination Cycle.

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