Plug-in Hybrids and Our Next Car

September 8th, 2021 by Potato

I was talking with Blueberry about global warming and transportation, as one does. We drive a Prius (and not much driving at that), but even then we still burn gas just to go get groceries or go to dance class. She looked up at me and asked the fatal question: “Can’t we do better? Is there a car that burns no gas, Daddy?” I had long been interested in hybrids and electrics, but hadn’t specifically shopped for a while, so I went and did that.

PHEVs in General

Electrify most of your driving. Save money, save the planet. That’s the goal right? So how do you best do that: with a plug-in hybrid [electric] vehicle (PHEV) or a fully electric battery [electric] vehicle (BEV)?

The answer was counter-intuitive for me: wouldn’t a PHEV be more complicated and expensive than a pure BEV, having two powertrains? Maybe more complicated, yes (though not much more than a hybrid, which are also counter-intuitively more reliable than their pure gas counterparts), but to cover most daily driving you only need a small bit of batteries, so perhaps not more expensive.

I came across a very persuasive argument that helped shift my perspective: you want to electrify your normal driving, and that takes an electric motor and a certain amount of batteries, 10-20 kWh or whatever. Then you want to not have range anxiety by having barely enough juice for your daily drive, so you have to add something to provide that cushion. One way to go is to add another 40+ kWh of batteries to provide a longer range. Or, you can add a gas engine and all its accoutrements for that extra range. And it turns out that with the price of batteries still so high, the gas engine is still considerably cheaper than adding more batteries (and has some added convenience in not having to learn about fast charging networks — you can keep using regular gas stations on long trips).

On a fleet level, the PHEV approach also makes sense if batteries are in limited supply and a production constraint (and for now and the foreseeable future, they are). A GWh worth of batteries can make so many BEVs, or ~4-6X as many PHEVs, and all those PHEVs would do a lot more to reduce our emissions than a few BEVs. This article on that topic coincidentally popped up as I was writing this post, so go there for more.

Eventually when batteries aren’t a limited supply, and if battery prices come down, then that intuition about pure BEVs being the better choice will be true… but for most people with typical driving habits, PHEVs are the way to go for now. And as a bonus, you don’t have to install a charging station at home (you can recharge overnight from a regular 110V outlet) or learn about charging networks for trip planning (just switch over to gas-burning hybrid mode and hit a regular gas station).

I barely drive these days, but still came out ahead picking a hybrid, on top of the environmental benefits of burning less oil. PHEVs are nearly no-brainers (in part thanks to government subsidies) in the same way, thanks to the cheaper cost of electricity (in most jurisdictions) and better efficiency of electric motors. Even with just 8000 km per year of driving, and just 75% of that electrified, I’d come out ahead picking the plug-in version of the Escape or Prius over the hybrid version (and way ahead of the gasser version). If you drive like a normal person, the benefits can be huge.

If you’re shopping for a new car and aren’t at least looking at the PHEV options out there, well, go do that!

However, there is a trade-off with many PHEVs: those batteries and powertrain take up space. The Prius is a remarkable car for its efficiency in space and what we’re able to cram in the trunk. The Prius Prime is really cool, incredibly efficient… and unfortunately loses a hefty chunk (~1/4) of that versatile trunk space (plus the spare tire). Fortunately, the newer SUV PHEVs (Ford Escape and Rav4 Prime) have found ways to put those extra batteries under the car and are basically zero-compromise — they even keep the spare tires. But it seems you have to go up to that SUV size class to get that storage space along with everything else.


Of course I have a spreadsheet to help do the comparison math. As always, download it or copy to your own Google drive rather than ask for permission to edit the template.

It should be pretty straightforward to use: enter your competing options, how you plan to drive, the consumption figures, and the cost of your fuel sources (electricity or gas) to get a comparison of the 15-year cost to own. Lots of simplifying assumptions: no inflation or other needless complications built in this time. It doesn’t consider resale value after 15 years, so perhaps a 20-year period would better capture full lifetime costs (which should be easy for you to change).

Getting your estimate of vehicle purchase costs should be easy (all[?] manufacturers’ build-and-price tools look to include the federal iZev and provincial [BC & PQ] incentives). Gas price is easy to estimate, though will be the most volatile in the future. Fuel consumption figures are listed, though getting kWh/100km and battery sizes can be a little harder (I added a way to estimate it from the battery size and range if you like, though it’s likely easier to just convert back from the Le/100km figure which should be listed in the specs somewhere). Electricity costs can also be a bit trickier to find as there can be delivery charges and time-of-use issues. Here in Toronto the headline number for off-peak usage is 8.3 cents/kWh, but there’s HST and a delivery charge (1.5 cents/kWh), so I’ve put 11 cents/kWh in. If you want to get fancy, you can add scenarios for off-peak and on-peak charging, but I’m already teetering at the edge of the rabbit hole.

I built in a 7% loss of efficiency for charging. Finding a more precise number will be hard until more people have the cars in their hands and try to measure it, but that should be close enough to capture that factor. (What is that, you ask? Well, it usually takes more than X kWh of electricity to fill a X kWh battery — some will be lost as heat, or used by the control electronics and cooling system during charging. It can vary depending on the model, the weather, etc., and it’s not reported in a standardized NRCan test, so unless you want another dive down the rabbit hole, take a rough estimate in the 5-10% range).

Aside: Not all PHEVs Are Created Equal

The magic of a gas-sipping hybrid car is not in the regenerative braking or cruising on EV mode, though that’s the sizzle that many auto journalists focus on. No, the big fuel savings comes from the Atkinson-cycle engine, which is more efficient at converting energy in liquid hydrocarbons to motion down the road. But you can’t put an Atkinson-cycle engine in a regular car because its acceleration (peak power output) sucks balls — the magic of a hybrid is using the electric motors and battery to cover you for those acceleration bursts, letting you get much better fuel economy from that more thermodynamically efficient engine (plus the extras like regenerative braking, turning the engine off when not needed, etc.).

For some reason, many PHEVs seem to be just a battery and electric motor slapped on to a conventional car that still has an Otto-cycle engine and conventional multi-gear transmission, and as a result get shoddy fuel economy once the battery runs out. So to me that was an important filter: is this a top-to-bottom hybrid that can also plug in (which should solve that worry about added complexity), or is it a conventional car with an electric motor hack? I almost immediately dismissed a number of offerings for that reason.

Though an alternative point of view is that it really doesn’t matter — if you do ~90% of your driving on pure electric, then who cares if it’s a gas guzzler for that occasional trip beyond EV range?

Another issue is that PHEVs have a bad history of being discontinued (perhaps “as the market evolves rapidly”, or perhaps just bad luck). The Volt had many, many issues as it was being birthed into the world (and I was super-critical of its apparent half-hearted development back in the day), but seemed to meet a genuine need once it finally made it to production, and meet it well. But now you can’t buy it any more. The Honda Clarity made it less than four years. The Ford C-Max and Fusion Engeris are both gone, and the Prius has gone through three plug-in iterations in just two overall model generations (but is still on sale and if it had a larger trunk would already be in my driveway).

However, I think that the automakers are starting to figure it out. The Rav4 Prime appears to be a massive hit (helped by the fact that it’s pleasing the moar power crowd and the green crowd at the same time with zero sacrifices). I don’t see quite as much hype for the Ford Escape PHEV, though it was delayed by over a year, and doesn’t have the perk of holding the Autobot Matrix of Leadership (i.e., it may need a cooler name to distinguish itself from a regular Escape. The Escape Lightning?).

I haven’t done a hybrid/primer post in a while, so hopefully that general stuff helps you (and nudges you to choose a hybrid or PHEV for your next car). Tomorrow I’ll get into the personal hand-wringy part of trying to decide what to do.

The Big Picture

And of course, I’d be remiss in not mentioning that as much as choosing your car well can help save money and the environment, it’s even better to not drive at all: taking public transit, walking, becoming a hermit in the woods free of the modern world’s burdens, biking, or carpooling when you do need a car to get somewhere can be good alternatives.

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