Does your car need to be 100% EV to be helping the energy transition?

This article is the second in a series I am writing on energy transition and decarbonization focused on the effectiveness and efficiency of our collective decarbonization journey. In case you missed the first one, it's here. (4) Post | Feed | LinkedIn

For this article, let me start with a note about me to establish some credibility with you in regards to EVs, engineering, and cars, in general. I have worked in the R&D department of a Tier 1 powertrain supplier where I was involved in the development of some radical engine designs to achieve high fuel economy and in manufacturing technologies for vehicle 'lightweighting', which ultimately evolved into volume manufacturing with magnesium alloys for major OEMs. I have spent the last 16 years in consulting engineering and technology commercialization, where among my duties, coverage of battery energy storage consulting services for electrical power grids was a key component. I am an early adopter of EVs, starting with a 2012 Chevrolet Volt Plug In Hybrid (PHEV) that I bought used in 2015, followed by 2017 Tesla Model S 75D (100% BEV) that I bought used in 2021.  I've also owned 22 vehicles prior to that (which you can read as me being 'a car guy' and something of an automotive tourist), and even restored some vintage vehicles within that group. 

If you want to sell something, it helps to have something that people either find cool, useful, or cheaper, right?  EVs are most of that, but maybe one size doesn't fit all, and maybe that's hurting us in reducing CO2 emissions.

I want to tell you a funny story about rolling up amongst my petrol-head friends (who mainly drive pick-up trucks) with my Tesla. When I give them a ride in it and mash the accelerator, the reaction is always the same - first come the expletives, then comes the giggling like a school-aged child.  After they've sorted themselves out from the "face-melting acceleration", they ask how much it costs to charge. Rough math when charging at home - 1-3 cents per km, depending on the price of electricity and time of year, and then I tell them I did the same math for my prior Chevy Volt at 8-9 cents per km (also not a terrible number) when running on the internal combustion engine (ICE) alone; with that information in hand, they all want an electric car.  In Canada, they also ask how the winter range is and after I explain that there is some noticeable range reduction in the winter, then they are less enthusiastic, but still excited. 

So, why aren't we all driving EVs now and why are US EV sales going flat (see Ted Nordhaus's article, link at bottom)? People like them, right? They are cool, they are useful, and potentially cheaper. 

Toyota did some interesting work to think about their own products and has publicly stated their position on BEVs (meaning 100% EVs) that they do not envisage their future sales being anything other than a mixture of technologies, from BEVs to PHEVs (grid plug-in hybrids of batteries and ICEs), hybrid vehicles (ICE plus electric motor and batteries on-board, but not capable of plugging into the grid to charge), and ICEs of various stripes and colors. Toyota's analysis was to consider a hypothetical fleet of 100 ICE cars with 250 g of CO2 emission per kilometer and a limited supply of lithium, enough for 100 kWh (most BEVs you can buy now are in that range, my 2017 Tesla has a 75-kWh battery) in total. If that 100kWh were provided to just one battery, the Toyota estimate was that the fleet's average emissions would drop by 1.5g/km (to 248.5 g CO2/km) or less than 1% reduction (let's call that Toyota Case 1).  However, if that 100kWh were divided up into 1.1-kWh batteries to supply 90 vehicles (and leaving 10 as full ICEs), the fleet average would drop by a full 45g (to 205 g CO2/km), equal to an 18% reduction (call it Toyota Case 2). Fascinating, right? 

There's obviously a lot of sensitivity around that result, but the basic concept is pretty sound, and here's why:

1. Batteries provide torque to electric motors instantly, making them great for accelerating a vehicle, and depending on where the electricity is coming from, it's very low in CO2 emissions.

2. Internal combustion engines are only so-so at being efficient across a broad range of engine speeds. Ideally, they would like to sit at one RPM (for which all the parts, ignition system, fuel injection components, and programming of the engine are optimized for) and never move from that point. In case you've ever wondered why your newest car has an 8-speed transmission and not just the 3 or 4 speeds your parents used to drive, this is why.  Having many transmission gears gives the engine the best opportunity to sit at that optimal RPM independent of vehicle speed. 

3. The combination of #1 and #2 is quite powerful. Batteries do the accelerating, and ICEs chug along at their preferred operating point once up to speed.  That acceleration duty doesn't just have to happen from a dead stop - even acceleration from, say 50-80kmh, can be handled the battery/electric motor, during which time the ICE does very little other than have a chat with the transmission to please upshift so that its RPMs can stay where they prefer to be. When max power is required (up a hill or passing), the two systems work together, providing ICE and battery-electric power at the same time. 

4. A neat feature of most (all?) electric or hybrid electric vehicles is regenerative braking, wherein a generator (perhaps even the electric drive motor) is engaged and coupled to the braking system (front axle, usually) and produces electricity that can charge the batteries as the vehicle is slowing down.  This is not a meaningless amount of resistance; many EVs can be brought almost to a halt off of just the regenerative braking system. This feature will also help the emissions of the 90 HEVs in the Toyota analysis. Why waste kinetic energy as heat (fundamentally what your car brakes do) when it can be converted to electric energy instead?

What I have described above can be accomplished with a plug-in hybrid or an internal hybrid (no grid electricity to charge).  To make the internal hybrid work, the ICE needs to work just a bit more (and still pretty close to its optimal operating RPM) to charge up the battery for its accelerating duties.  Is the internal hybrid as efficient as a plug-in hybrid? No, it is not, but it reduces the functional weaknesses of a ICE-only solution.

Importantly, none of this is new. Different car companies have presented somewhat different architectures, but they are all accomplishing the same thing.  Volvo runs an electric motor on the rear axle while supercharging and turbocharging the ICE (for goals of performance or efficiency). Toyota has been building its 'hybrid synergy drive' for everything from the Prius to the Highlander for decades now (a big reason why Toyota's analysis and opinion on this should carry some weight). Porsche went racing 10 years ago with the 918 Spyder with a mid-engined ICE and electric motors on the axles at LeMans (24-hour race that prizes both performance and efficiency); what Porsche did was charge up the batteries the via regen braking and then activated the electric motors to accelerate out of corners faster. Audi showed us the Duo concept in 1990, wherein they modified one of their all-wheel drive station wagons with an electric motor to run the rear axle and kept the ICE connect in front-wheel drive mode; at the time, German cities were considering banning ICEs in urban centers to cut down on air pollution, so the Audi solution was to switch to 'city' mode at the touch of the button, becoming rear-wheel-drive, silent and pollution-less within the range limits of the battery (a bunch of lead-acid batteries in the trunk) that had been charged by the ICE earlier on (and, curiously, a solar panel on the roof - not much help, that, but A for effort).  The current Stellantis (Fiat, Chrysler, Lancia, etc.) group's Global Small Engine platform (launched 2016) starts as small as a tiny 3-cylinder 1L ICE (such as the Fiat 500) with a starter-generator and a somewhat enlarged battery to give it some oomph for the Italian mountain passes and autostrada from a very, very small engine. Certainly, some of these solutions are more elegant and evolved than others, but the basic concept is quite simple; there is complexity in the development and execution, but for the most part, the auto industry is already through that phase.

My 2012 Chevrolet Volt PHEV did all of its 'hybriding' by running the vehicle entirely on the electric drive motor until the battery was depleted and then it would switch on the ICE, which didn't actually drive the vehicle; rather, it merely provided electricity via a generator (being turned by the ICE) to the electric drive motor. By 2013, Chevrolet had gotten a bit more sophisticated and added the option to hold the ICE generator in the on position when cruising at highway speed so that the battery-only range could be doled out over a longer drive for in-town driving and acceleration.  For reference, the electric-only range on a 1st Gen Volt is about 60km from a 10kWh battery. The fuel tank was tiny at 25 Liters (vs 60+ for most cars today), the generator a 1.4L 4-cylinder, and would give a combined range of around 600km.  That made the vehicle around 5L/100km when on generator, also not too shabby in the ICE world, owing to the features of regenerative braking, vehicle systems able to run on battery even while idling, and a fairly aerodynamic shape, along with a few other features. One of those is worth mentioning - on cold days, the car would start on ICE (which is only about 20-25% efficient), use its waste heat to warm up the batteries to their preferred temperature window, switch over to batteries, run on electric until the battery temp dropped below a certain threshold, kick on the ICE to warm the batteries again, and so on. That feature is obviously only useful to drivers in colder places, but it is an interesting example of how a multi-faceted solution can be valuable (despite the obviously complexity of ICE/battery hybrid vs. the simplicity and elegance of 100% EV).

Everything above is a 'why are hybrids (PHEV or internal) good' pitch and gives us some confidence that we can get to Toyota's Case 2 without trying too hard. What about Toyota Case 1 where only one car had the 100kWh battery? How do we contextualize that case?

It's actually a slightly worse (not much worse) example than the real world is now. Rough math: 40 million EVs on the road now (I think that number includes the PHEVs) of a global passenger car fleet of 1.4 billion vehicles equals 3-4% EV penetration.  That penetration rate is obviously growing annually with some markets going faster than others (notably China and Europe moving along at a pretty good clip, but North America is sitting at about 7% of vehicles sales being EVs). 

In the Toyota case, why is the fleet benefit only 0.6% when the implementation rate is 1%? There are several reasons.

1. There is an inherent waste of an opportunity for emissions savings if the 100% EV gets driven to something less than its full range. Logically, that would be true always since it's unlikely that a charging station will always magically appear whenever the battery is at its precise moment of depletion; so, to be safe, the drive recharges with some state of charge remaining. This concern can be minimized by an optimized charging network, which is a work in progress. By comparison, the 90 cars in Case 2 with small batteries are likely to use the full charge of the battery regularly, hence the emissions benefit is also similarly captured. BTW the existence of a battery also enables regenerative braking as an efficiency technology - the capture electrical energy has to be stored somewhere before it can be dispensed again.

An aside here on EV charging: even when it's fast, it's still slow.  Liquid fuel transfer for a passenger car gives you 600km in a few minutes (longer, apparently, when it's a cold, windy day and you are wearing neither gloves nor a coat, but I digress...) whereas my Tesla's max charge rate on a Level 3 Tesla charger is around 600km/hour. In terms of adoption and how people want to use their vehicles, this needs to be considered. 

2. Embedded in the Toyota analysis is another current problem with large EV batteries: since their energy density is quite low (ten to 100 times less than that of gasoline), they are fairly heavy. That ratio needs some explanation and adjustment (a lot, actually): some of that hydrocarbon energy density benefit is lost in all the systems required to convert the fuel into forward motion, including the highly inefficient engine, its exhaust system, cooling system, multi-speed transmission, and so on. (Remember, I actually like EVs here!)  

Drawing from what we know about all cars and physics, heavier, more powerful engines require stronger frames and suspensions, bigger wheels, bigger tires, bigger brakes, and so on. The interesting Catch-22 about the introduction of all these heavier components is that some of the benefit of the bigger, more powerful engine also gets lost, at least when accelerating and cornering. At steady speeds, none of this matters; big powerful engines only run at minimal load and the dominant resistive force to forward progress is aerodynamic drag, defined by the shape of the vehicle, not its mass. EVs follow the same physics.  The heavier the battery, the greater the proportion of its output goes to accelerating its own mass, the now-enlarged chassis/suspension components needed to support that mass, and not the mass of people and cargo.  

OK, so to summarize: Toyota Case 1 is the real world - a few, but highly battery-endowed EVs with no real impact on emissions, and Case 2 looks pretty good to reduce emissions by 18%, but clearly not enough in the fight against climate change to call it a win on the road transportation front. 

What happens next?

Conceptually, I think that Toyota wanted to make a point that improving the fleet efficiency from some relatively modest technology changes could make a meaningful difference.  Consider for a moment if Toyota had doled out not just 100kWh of batteries among 100 vehicles, but something closer to 1000kWh. That would be interesting - a world of Gen 1 Chevy Volts giving people most of the driving range they normally use under grid-charged battery power and extending the range when needed via a small engine and fuel tank. 

Toyota operates in many markets around the world where the electrical grid is neither clean nor reliable for daily use or vehicle charging, so a 100% EV commitment is simply not a viable promise to make to the world or its stakeholders. To underscore that, an energy executive I met in South Africa said to me, 'climate change is a nice problem to work on, but it's a Northern Hemisphere problem; we have much more fundamental issues to deal with in Africa.'

Gill Pratt, CEO of Toyota Research Institute, is quoted as saying, "What has to change is that we have to mature a little bit, and we have to stop doing wishful thinking. A real discussion is that these are the constraints in the development of resources in the world, both material resources and charging infrastructure and renewable power... If that is true, how do we reduce the total amount of carbon dioxide that will accumulate? That is a mature discussion, not a kind of dream discussion."

One criticism of the Toyota analysis is the starting assumption that only 100kWh of battery materials are available.  Why not just arm 100 of those vehicles with 100kWh of batteries and drop the 250g of CO2 emissions right down to nothing?  The more EV batteries we make, the cheaper they get, the more affordable talepipe emission-free vehicles there are on the road, yes? It appears to be a win-win scenario. That is the ideal state we are trying to get to. 

We know that there is enough material (lithium, nickel, cobalt, etc.) in the ground to make a lot of batteries.  The challenge is the timeline we are on and the timeline it takes to develop a sufficiently-size supply chain, beginning with the raw minerals at the mine face.   My understanding (from having spent around 15 years in an engineering company with a heavy focus on mining and metals) is that a typical nickel deposit takes about 10 years to commercialize.  Several very intelligent and thoughtful engineers and consultants I know have done an extensive and important amount of work on comparing the projected market demand for batteries with the mining industry's ability to supply those materials in time with the demand. Not surprisingly, they found some gaps, gaps that may explain why we saw prices skyrocket in the past two years for the major input materials required for lithium-based batteries. Those price increases also dampen the business case for EVs.  The situation is probably also not helped by the fact that the entire energy transition is counting on energy storage; if renewables are one of the major arrows in the fight against climate change, they need firming capacity - as that gets more expensive, so does the whole prospect of an economically rational energy transition. Interestingly, some of the outcomes of the work on material supply gaps includes advocating for battery designs that rely less on nickel and cobalt in favor of iron and phosphate, materials that are more abundantly available now.  As promising as that sounds, those latter designs have lower energy densities and do not help the mass problem (that ultimately affects battery size and EV range). Another point in favour of hybrids - for now, at least - until engineering and material supply can catch up to everyone's EV dreams. 

The dominant thinking is that in energy transition, every gram of CO2 matters and therefore anything short of driving with 100% electrification and a full ban on ICEs is pointing us to inevitable doom. 

One version of how this all plays out is this:

1. Large-scale adoption of 100% BEVs with large batteries.

2. Vehicle charging locations become ubiquitous, including the large-scale redevelopment of our urban centres to support the necessary power input requirements.

3. Excess battery capacity is meaningfully utilized to stabilize a high-renewable penetration power grid by vehicle-to-grid (which is no easy feat on its own) technology.

4. In due course, EV batteries come down in size again due to the omnipresent ability to charge, perhaps coinciding with autonomous vehicles, autonomous ride-hailing fleets, and reduced individual vehicle ownership.

5. Old EVs become low-performance grid batteries, and/or battery components are recycled en masse to produce new EV batteries. 

That sounds ideal and generally inline with how we might think of a decarbonized transportation future, but we need to be realistic about the timeline.

There are some significant interdependencies within each of the steps above, starting with needing EV adoption to grow.  However, there are extensive challenges embedded in just that first step, including near-term availability of materials (not to be confused with an overall availability of materials) at acceptable prices. 

If we believe the Toyota example and our goal is indeed CO2 emissions reduction as quickly as possible,  any amount of vehicle hybridization helps the cause and gets us closer to a point where charging infrastructure, V2G, battery developments, material supply and other adoption-dependent infrastructure can take off or simply go through its normal development timeline (which can take years). The critic will argue that throwing more money at the problem will speed up the timeline, but with all respect, industrial 'tech' development is slow - it is not like developing 'tech', i.e. smartphone apps.

Encouraging more hybrids also avoids the need for consumers to make an all-or-nothing choice on 100% EV or no EV.  

For some consumers, 100% EVs are a must-have product and it fits their needs now: terrific. But, there is also a very large set of consumers for whom a 100% EV currently does not fit the bill - that is evidenced by market uptake or lack thereof.  With that in mind (and going back to my giggling muscle car friends), even a Dodge Ram pick-up could be improved from a performance-, emissions- and operating cost- perspective with additional hybridization. It doesn't have to be binary, F-150 Lightning or nothing.  All the technology exists, doesn't require exotic materials, and we've been using it for years.  

I actually first stated my opinion as far back as 2010 or 2011 that we'd get further along with hybrid-electric vehicles with small batteries than with 100% EVs with big batteries - recipients of that opinion generally looked at me like I was from the moon at that time.  It is interesting to see that others are bringing this idea forward now, and I have drawn on some of their material for this article.

If you are a consumer and looking to buy a new car and you are not quite ready for the 100% EV jump, don't stress: look for a hybrid, ideally a plug-in hybrid. You'll get all the benefits of an EV and none of the current limiters. You will like it and your wallet will, too, with less trips to the gas pump and probably lower maintenance costs.  And, you will help the energy transition along the way.

If you are a car manufacturer, I encourage you not to throw away the 100+ years of ICE development just yet - the large-scale adoption of 100% EVs is actually beyond your control because of everything else that needs to come with it to make 100% EVs the answer for most consumers (today). Use the hybrid technology and experience that has existed for decades to make more customer-focused vehicles now.

I welcome you thoughts and comments on this. If you like the article and think others might to, please repost.

Interesting related reading and references.

Are plug-in hybrids booming or fading, and are they better for the climate? (sustainabilitybynumbers.com)

Toyota Calls On Science To Tell EV-Only Extremists That They’re Wrong (insideevs.com)

Could Climate Hawks Dream of Hybrid… | The Breakthrough Institute

Are LFP batteries the key to meeting North American electric vehicle demand? How previously overlooked chemistry helps overcome headwinds to mass adoption (hatch.com)