Professor Obvious Wants A Word

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Professor Obvious writes:

“It should go without saying that for electric cars to make any sense at all, they must ONLY be charged when it’s sunny or windy. That makes them part of the solution to intermittency. If they are charged when it’s neither sunny nor windy, they are part of the problem, because either (a) they’re being charged by fossil fuel, such as natural gas peaker plants, or (b) they’re using up precious grid-scale storage to charge themselves when they are themselves an excellent form of electricity storage.”

The context here is that solar electricity has gotten delightfully cheap in recent years, but what hasn’t changed is that it can be counted on to produce exactly nada during roughly 16 hours out of each 24. So, plugging in your EV (Electric Vehicle) at night, or in the evening, is (so to speak) a non-starter.

(Wind energy has gotten cheap, too, but its intermittency is of a different kind. In this post, I’m mostly going to talk about solar. I’ll also note in passing that if you live someplace with abundant nuclear power, then night is the very best time to charge your EV, because nuclear plants like to be kept running all the time, and produce excess power at night, when demand is low.)

As we unpack this, it’s clear that we need to put some processes in place if we want to take full advantage of the transition to EVs. I understand that we are still just getting started in that transition, and that everything can’t happen at once, and that we should be grateful to those who are diving in and building cars. At the same time, early decisions have a way of getting locked in, so we want to set the right course while we still can. Here are some things that won’t happen overnight, but need to start soon:

1. Workplaces (particularly offices), and not homes, must take the early lead in providing charging points for EVs, so that charging can happen during midday, while the cars are parked at work, using predominantly solar electricity.

2. EV charging stations should be required to be hooked to a web-based service that tracks the moment-by-moment, regional supply of renewable energy, and adjusts the charging rates of all connected vehicles up or down accordingly–to the point of turning off charging altogether when there is no solar or wind energy to be had (if we really do care about burning less natural gas). This will be complicated. Prudent EV owners will have to plan ahead based on forecast conditions (such as a couple of expected overcast days) and make sure their batteries are topped off to avoid being caught short. There will have to be some provision for emergency/priority charging, but it will need to cost more, or everyone will just use it all the time. This is a great use case for a hefty carbon tax, which would give EV owners choice, while making them accountable for the extra emissions. If you want charging on demand no matter what, pay more. If you get tired of paying more, then either plan ahead better, ride the electric bike more and use the car less, or find some other way to adapt. But even with that kind of system, we can expect some EV owners to be angry when they’re leaving the office if they find their battery less charged than they expected.

3. At present, EVs are rather expensive, and so a large proportion of EV owners are members of the professional/ownership class who are likely to work in offices during “standard” working hours (something along the lines of 8 to 5), assuming the Coronavirus disaster does eventually end. That’s why I said above that installing chargers at office buildings should be first priority. But if EVs are widely adopted, this will change. More and more EV drivers will be people who aren’t necessarily sitting in an office during the sunny hours. And electrified delivery and service vehicles of all sorts will be on the move for much of the sunny time. To deal with this, the first order of business is to make sure that charge points are widely available to these more mobile vehicles for short charging bursts (lunchtime, while unloading a delivery, etc.). In connection with this, it would be smart to give priority juice to these vehicles that are known to have fewer daylight charging opportunities. As for the second order of business…

Oh, I see Professor Obvious is waving his arm vigorously; he has another point to make. “Why can the batteries ONLY be charged while IN a vehicle? Wouldn’t it make a lot more sense to have modular batteries that can be swapped in and out? So that while the UPS truck is running around all day, the battery it’s going to use tomorrow is sitting in a charging rack with a bunch of others, basking in solar-generated electrons?”

Yes, Professor, you’ve lived up to your name yet again. All EV batteries should be modular (able to be removed from any vehicle and plugged into any other vehicle) if we really want them to be worth a damn for carbon reduction. Battery designs should be standardized1, and it would add very little to the cost of an EV to make the batteries swappable, in a few seconds, without a human doing anything more than pressing a large, friendly button. For vehicle fleets, like mail trucks, UPS and FedEx trucks, rental cars, and so on, this will almost certainly happen, because the alternative (a bigger fleet) is much more expensive. For personal vehicles, the main issue is that Li-ion battery packs are not truly fungible; they work less well as they get older, and the specifics of how they are used can make them age faster or slower. (For example, charging them at very high or very low temperatures can cause permanent loss of capacity.) So the owner of a prestige vehicle like a Tesla doesn’t want to get stuck with a crummy battery, especially if their car is relatively new and they take good care of it.

On the other hand, swappable batteries will come in very handy for personal vehicles too. On a long road trip, or even in the middle of a busy work day in the city, would you enjoy waiting, perhaps for an hour or more, for “your” battery to charge before you can get moving again? Or would you prefer to wait 30 seconds (faster than a gasoline fill-up is now!) for a different battery, fully charged by yesterday’s sunshine, to be snapped in by a robotic gadget?

But, since we seem to hate low-hanging fruit (which is an emerging theme of this blog), we’re spending billions instead on research to make entirely new kinds of batteries that can take in power at such terrifying rates that they fully charge in a few minutes. That’s an inherently very hard thing to do, and while it would be nice to have for some applications, for EVs we simply don’t need it. Because swapping batteries is inherently dead simple and dead cheap. (Why do we hate things that are dead simple and dead cheap? Are they just too boring for our novelty-addicted minds?)

While we’re on the subject of “things that are obvious about EVs,” there’s another one that deserves mention here, because it certainly seems obvious to many renewables fans. That’s the idea of connecting EV batteries to the grid, and using them as grid energy storage when they’re not driving around, particularly at night. It does make sense: EV batteries represent a very large percentage of all rechargeable batteries right now, and possibly well into the future (depending on whether EVs or grid batteries grow faster–my money is on EVs winning that race for at least the next several years). So, why not use those kilowatt-hours, instead of natural gas, to keep the power going at night?

(When I say “at night,” of course what I really mean is “when there isn’t enough renewable power to run the grid,” whether it’s due to night, cloudy weather, or a lack of wind. At the beginning, I discussed the need to avoid charging EV batteries at those times; it’s a natural extension to see if we can power the grid at some of those times by “un-charging” the EVs.)

It’s a sound idea technically, but will be a hard sell politically. Just as EV owners think of the battery as “MY battery,” they also think of the charge it holds as “MY charge, which I already paid for, this is America not Red China, etc.!” Certainly anyone whose EV strands them on the highway because PG&E chose to drain their battery a little too hard last night is going to be killing mad. For the idea to work at all, there would have to be an online system where you could register your plan to go on a road trip tomorrow so that PG&E would leave your battery untapped–a system which would not only beg to be abused, but would be several notches too socialist for many Americans. (“MY battery.”) And what if the need for the road trip comes up at the last minute? A family member falls sick and you have to jump in the car and start driving? Maybe PG&E has to provide you with a free, fully-charged rental in that situation, if they haven’t left your car enough charge…more paperwork, socialism, opportunity for corruption. I’m not saying it could never happen, but it won’t be easy.

In fact, all the obviously good ideas in this post are going to be unpopular: not charging your car at night in your garage, limited charging when renewable power isn’t available, swappable batteries that are not your personal property, and your battery being hijacked (I mean “borrowed”) for grid storage.

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I don’t honestly know if, as a society, in order to realize all the potential benefits from the transition to EVs, we’re willing to stand up to that level of red-blooded individualist ire. If it turns out we are, we might as well take it one step further and get rid of personal vehicles altogether, with very few exceptions. Don’t just get over yourself with the “MY battery” thing; get over the “MY car” thing too. That means opting out of the love affair with the automobile that’s so deeply rooted in the American psyche. My personal crystal ball thinks that (a) it could happen, and (b) it won’t happen until we’re surrounded by a level of climate calamity that’s bad enough to make our sacred cows start saying, “moot! mooot!2

Self-driving car enthusiasts have for some time been suggesting that our attachment to our personal cars will wither away, once we get used to the convenience of driverless transportation on demand. My personal opinion is that self-driving cars that can operate safely on ordinary roads are many years away, if they happen at all–a view that seems to be less heretical than it was a couple of years ago. In fact, we can do self-driving cars safely with current technology, but we have to simplify the context in which they operate, simplify what we require them to “understand.” Maybe separate them from other traffic? And put them on rails, which are far more energy-efficient than tires on asphalt anyway? But that’s mass transit trying to sneak back into our lives (it never should have left), and that’s another post.

Meanwhile, Professor Obvious has overlooked an alternative solution to all these complicated problems, one which is universally adopted and likely to remain so: just let red-blooded American EV owners charge their cars and manage their batteries any old way they want to. And don’t go making any unpleasant comparisons between the carbon benefit we get from EVs, and the carbon benefit we could have gotten. In fact, just shut up.


  1. Of course some vehicles have more battery capacity than others; one simple way to handle that is to size the battery modules so that, for example, a Nissan Leaf needs 3 modules of 10 kilowatt-hours each, and a Tesla needs 8 of the same modules. We can also have a couple of sizes, like giant AA and D cells.
  2. Worst. Pun. Ever.

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