Battery EV or Fuel Cell EV?
BEV or FCEV Infrastructure?
By Toby Kinkaid
BEV or FCEV infrastructure, which is best? A sea change has happened with the advent of Electrifying transportation. Excellent. However, there is a disconnect in the discussion or debate about EV infrastructure: which type?
Today, most “experts” and public policy makers are all buying into the Tesla worldview of things. Everything will be powered with Battery packs.
So widespread is this view that the entire language of EV has been hijacked, in effect, to mean only one thing: battery electric vehicles (BEV). Mention Fuel Cell EV to most policy makers and battery fans and you mostly get a contorted stare.
In fact, however, there are two types of EV’s: Battery EV (BEV) and the Fuel Cell EV (FCEV). Up until this time, these required separate infrastructure entirely. A Battery EV uses electrical charging using Level 1, Level 2, and DC Fast Charge categories of charging rates. The FCEV uses Hydrogen fuel as the energy carrier, not electric charge.
A fuel cell EV infrastructure, fueling with Hydrogen, used to require an entirely different infrastructure and so the two worlds have been at odds. Well, said fairly, the Battery EV advocates following the Tesla language and worldview have dominated not only the discussion around the infrastructure needs, but the entire meaning of EV. To great effect, most public funding for “EV” infrastructure is exclusively focused on Battery EV charging.
A few years ago (See image to the right) the World Bank issued a very famous one-pager called something like “Cars – Battery Electric most efficient by far. I add a “?” mark to that claim as the reasoning behind this graphic, which spurred Billions of dollars in EV battery charging investment – is deeply flawed.
Let’s start with what is claimed. The graphic attempts to compare Battery EV charging with a Green Hydrogen fuel cell fueling system both with a renewable energy front-end.
The conclusion of the study is shown at Battery EV 73% efficiency. The green hydrogen system efficiency reported at 22%. Their conclusion? Battery EV is three times more efficient. Right?
Not so fast. Who ever prepared this chart ignores something so fundamental to analysis that it begs the question of understanding the nature of renewables: variability and capacity factor.
Capacity factor is simply the availability of a given resource in 24 hours. Although the BEV and FCEV system each use renewables on the front end, the problem is it “assumes” the BEV EV’s are plugged in! How often are BEV cars actually plugged in?
Renewable energy is a realtime prospect. Use it, or lose it. If you don’t have a load hooked up in real time – then the renewable energy is wasted.
If there is no load on the grid, then an overproduction of renewable electricity must be curtailed. It must be turned off. The assumption of the graphic is that the BEV cars and trucks are plugged in all the time. They assume that any renewable energy somehow finds its way into a car battery all the time. This is not true in the real world.
If a Battery EV (BEV) is not actually plugged in to receive renewable energy – then it’s not as advertised. Charging batteries is a real time prospect. If the BEV is not physically connected, then you can’t claim 100% renewable input – as the graphic assumes.
On the green hydrogen side (FCEV), however, the renewables are connected to the electrolyzer 100% of the time. This means that you’re able to capture and deliver to the electrolyzer whatever renewable energy you happen to produce. Renewables are still variable, but with the wires connected 100% of the time to the electrolyzer you’re able to utilize nearly all you can produce.
How often are BEV cars plugged in? Perhaps 15% of the time? This is a real issue totally ignored by the Global Bank graphic. Further, all waste heat is “assumed” to be lost which is not true if you use the heat for something useful.
Using a real 15% capacity factor for BEV access the real efficiency is not 73% as claimed, but rather closer to 11%. The graphic implies that the renewable energy is put on the grid, but this is a rough assumption, as again, with no direct load the grid operators may curtail the renewable energy input.
The numbers on the bottom of the chart are from me as corrected figures. Taking into account the use of waste heat the green hydrogen system increases in efficiency.
Even so, if you take the original numbers BEV 73%, and FCEV 22%, respectively, and apply the 15% capacity factor to BEVs as it should be applied, then the actual BEV efficiency drops down to 11%. Charging BEVs with renewables is half as efficient as the green hydrogen system efficiency, not three times more as claimed.
That’s a big difference and delivers a totally different conclusion. Which powertrain from renewables is more efficient “BEV” or “FCEV”? In reality, the FCEV is the more efficient powertrain powered with 100% renewable energy.
As a system efficiency BEV comes in around 11%, with FCEV delivering around 22% in a real world use case. From a big picture perspective using a FCEV paradigm would require around 50% less total energy to move our world fleets if we transition from BEV to green hydrogen fueled FCEV for all vehicle types.
BEV or FCEV
Weight vs. Range
Before we get further into infrastructure requirements for EV electrification let’s talk a bit about logic.
The Chart to the right talks about Weight versus Range for the two respective EV types: BEV and FCEV.
The Battery EV paradigm is much like a turtle – you carry your house on your back. A large EV Battery pack weighs the same fully charged or empty. If you deplete a battery pack all of that unused battery weight is just that – dead weight. And, like a turtle a BEV hauls around its house on its back. Multiply this by millions of vehicles and it becomes clear this is not a good design. That’s a lot of dead weight being moved around – by millions of vehicles every day? Not very practical.
Plotting the relationship of Weight versus Range we see to increase range for a Battery EV you only have one choice: ad more batteries. More batteries means more weight and you end up with a diminishing return.
Fuel cell EV powertrains don’t increase in weight appreciably using more Hydrogen fuel as you increase range: this is a good thing. FCEV can add range just by increasing the capacity of the H2 storage tank. Adding minimal weight the range can be extended greatly.
Comparing BEV with FCEV if you have work to do? FCEV wins using clean green hydrogen fuel with fast refueling times, and do direct negative grid impacts as green hydrogen fuel can be produced during inexpensive off-peak times.
How many more vehicles other than just light duty battery vehicles can be powered with a clean hydrogen Fuel Cell EV? All of them.
The real question is how to power cars, trucks, vans, buses, semis, front-loaders, dump trucks, construction equipment, maritime shipping, tractors, combines, aviation and yes, heavy industry. You can’t make steel or cement with batteries. You can with green hydrogen and that’s the point.
How many different Vehicles are we Talking About?
The real question is how can we replace Internal Combustion Engines with Fuel Cell engines? How do we replace toxic fuels with non-toxic fuels. There are two things we need to do: replace the engines from ICE to Fuel Cell, and replace the fuel infrastructure from toxic fossil fuels to non-toxic green hydrogen fuel.
This is the greatest economic opportunity of the industrial age. Replacing old, dirty, noisy, expensive and short-lived systems (ICE) with fuel cell engines – with only a few moving parts – is the answer. Fueling these Fuel Cell engines with locally produced green hydrogen is also the answer. Together, we have a sustainable, growing and equitable world. Isn’t that our goal?
The economic opportunity for the world replacing ICE with fuel cell engines is the path we can take. In this decade we must all focus on doing this one thing, doing the same thing: replacing ICE fleets both public and private with FCEV fleets using Green Hydrogen fueling infrastructure.
Before today, there was a debate, if you can call it that, as FCEV have all but been erased from the language as “EV” usually refers to the “Battery EV.”
This is changing today with innovations in technology standardizing the infrastructure to provide both DC Fast Charge for BEVs and H2 fueling for FCEVs – all using the same infrastructure.
At the bottom of the sketch to the right is a comparison between battery EV, light duty vehicles, to FCEVs which encompass all vehicle types: light, medium and heavy duty classes. How about ships?
Battery ships are material intensive and worst of all, having a low energy density in comparison, takes up too much volume – the business end of shipping. For industrial transportation the fuel cell EV works.
The battery paradigm if we consider at scale – is wishful thinking – and impractical. We need to replace the fossil fuel drivetrain with non-toxic green hydrogen systems and power all our machine types with clean fuel.
Isn’t that what we’re trying to do? The all Battery EV paradigm ignores so many realities, especially materials and grid impacts that it makes one wonder. Have we lost sight of our actual goals? Electrification of transportation.
Thinking you can do the whole job across sectors with Lithium-ion batteries is akin to a big lie. It can’t happen due to these and other major limitations – so it won’t.
Our world runs on fossil fuels. Our world needs to run on Green Hydrogen fuels.
This transition is our greatest responsibility, and opportunity, to bring real energy dignity and non-toxicity to our local communities and economies everywhere – relatively all at once. We’re in this together – let’s make a common solution which can be applied everywhere for any power and energy demand you have. Let’s unleash the greatest mover in industrial history: profit and need.
Attempts to Support BEV infrastructure
In Hawaii, the EV question is raised by some, but policy makers and the energy “Intelligencia” have been focused on EV equals Battery EV. As with many municipalities they’re largely thinking about charging batteries. For a small isolated grid as exists on each of the Hawaiian islands – this will be very challenging.
If you’re thinking is only limited to charging questions, then you may miss the forest for the trees.
The sketch on the right begins with a typical EV charging scenario. Grid to EVSE (electric vehicle supply equipment) which is everything in between the car and the charging source, usually the grid – typically power conditioning equipment and the dispensers themselves.
All Battery EV charging is done in real time. BEV and FCEV infrastructure must take this under consideration. This is the problem for grid operators. Actually, two problems: unscheduled loads, and high short-term power demands which spike the system.
The usual discussion centers around renewable energy inputs to the grid as somehow making battery EV’s cleaner. Yes, for the times they are plugged in during renewable energy hours does work – for a single vehicle – but not en mass.
One DC Fast Charger, for light cars and trucks can now be rated at 350 kW charging power (70 houses of power for one car). Charge 1,000 cars simultaneously and the grid must provide 350 MW of power – a sizable power draw – instantaneous and abrupt. Not too easy if you’re a grid operator.
Not too easy if you’re a Hawaiian Island. 350 MW is nearly 1/3 of Oahu’s grid. To DC Fast Charge only 1,000 vehicles at the rate of 350 kW. Doesn’t sound like a practical idea, but is getting nearly all the funding for EV’s on Oahu. Is this workable?
Battery EV’s are plugged in around 15% of the time, so how can you say renewable energy charging a battery EV is clean? It’s not. In reality, the “clean” part of charging depends on the real mix of power sources in that moment.
If it’s 100% renewable as is green hydrogen, then you’re clean. But, if you’re over 80% fossil fueled on your grid, then battery charging is only marginally better than burning the fossil fuels in the first place. On Hawaii’s Oahu island, most of that energy is still fossil fueled.
Green Hydrogen systems offer a solution to both DC Fast Charge and H2 fueling. A combined standardized system which uses local renewable energy to drive an electrolyzer in real time making real fuel for local consumption with 100% no toxicity – is a practical solution. A real future for Hawaii – and for everyone.
Battery EV Charging Standards
There are two ways you can charge batteries: fast, or slow.
In the sketch at the top discussing the Global Bank graphic they use the figure of 95% round-trip efficiency for charging a battery. That is to include all losses charging, and all losses discharging.
Well, in a controlled laboratory setting, sure. When temperatures are ideal for the test battery, with slow charging rates, and slow discharging rates – everything is ideal. Including how often are the wires connected? Yes, you can get 95% under ideal conditions.
However, anyone in the real world knows that’s not how we actually use batteries. Especially large batteries now proposed for heavy transport. The temperature outside our cars are usually too hot or too cold for ideal conditions.
Batteries, however, are very temperature dependent. Batteries, especially Lithium-ion, are sensitive to hot and cold conditions. Batteries are a Goldilocks situation where they need charging conditions to be – just right.
Often, if it’s cold outside a Battery EV drivers will “YoYo” the car before fast charging, which is sudden accelerations and braking to induce more heat in the battery to warm it up before the fast charging session.
Batteries need to be conditioned to receive DC Fast Charge. If the batteries are too cold to charge, or too warm to charge quickly they must be conditioned. Otherwise, the batteries will slow down the charge rate to minimize damage and battery stress.
All of these real world conditions are totally lost on the Global Bank graphic and the real physics of life-cycle efficiency. The efficiency of a component is not the efficiency of a system. If “Capacity Factor” is inconvenient, then just ignore it?
DC Fast Charge and Grid Impacts in Real-time
Battery EV’s require charging. You can charge slowly using Level 1 – a plug in home level charger using a standard plug 120 VAC. Level one uses a standard J-1772 connector which is rated for both Level 1 and Level 2 charging. Level 1 is a slow charge used for long overnight charging sessions. Average charging time around 12 hours depending on your battery size.
The Power draw of Level 1 is around 1,200 to 2,500 watts (2.5 kW).
Level 2 charging uses your 240 VAC plug (often used for washing machines and stoves) and will charge your Battery EV in an average of 4 to 6 hours depending on the battery size. The Power draw for Level 2 is rated around 7.2 kilowatts (7.2 kW) about the draw of 1.5 houses with everything turned on.
DC Fast Charging is where we really get intensive with power draws ranging now from 50 kW to 350 kW or about 70 Houses with everything turned on. The voltages of the DC Fast Charge dispenser range between 400 VDC and now 800 VDC.
The higher voltages allow charging a BEV with high power transfer at lower current levels. Lower amps with higher voltage attempts to limit the I2R losses where resistive losses increase by the square of the current moving through a cable.
However, the reality is 70 Houses of power are being directed to charge a single vehicle. Is that a practical idea? Wouldn’t massive grid upgrades be required? Do some back of the envelope calculations as to powering a fleet and the impacts becomes very clear – Battery Charging our fleets is not tenable.
The MegaCharger (rated at 1.6 Mw) draws the equivalent of 320 Houses (average rated draw per house at 5 kW) to DC Fast Charge – one truck. To charge 1,000 trucks would require 1.6 GW of simultaneous power demand. An enormous power draw – for just 1,000 battery trucks. All in real time. If you’re a grid operator trying to schedule generating capacity and new trucks plug in, unannounced, then big trouble for the grid. And for us all.
