Resistance is futile

“How I learned to stop worrying and accept the self-charging hybrid…”

Whenever a new technology appears, you can be sure that there will be people who are quick to point out its flaws. Fair enough – progress is often iterative. We all make mistakes, and fixing flaws is how technology improves.

When it comes to electric vehicles, there is no shortage of easily identifiable problems to be addressed: too expensive! Not enough range! Dirty electricity! Nowhere to charge! Recycling! Lithium! Cobalt! Towing caravans!!

That’s cool. All the above are either fixed, being fixed or are fixable soon. No major showstoppers. Less than ten years ago many electric cars were primitive and slow. We cruised past those issues long ago.

More mystifying to me is the “<random technology> will be better one day, so we should just stick with petrol and diesel” viewpoint. Hydrogen fuel cells, synfuels, self-charging hybrids, pixie dust – all are apparently reasons not to do anything too radical, too soon.

Sometimes it seems that these conservative views have the upper hand. The negativity around “challenger” technologies can be relentless. They killed electric cars once before. What if they succeed again? Surely the EV advocates need to fight this battle? EVs must?win!

I think EVs have already won. Here’s why.

Let’s start with a generic family car, able to transport four adults with a bit of luggage. It’ll need approximately 0.7 million Joules (MJ) of energy into the wheels to make it go one mile (on average)[i] . That’s roughly equivalent to the energy you get from eating a small bag of crisps.

But there's more. To get energy into the wheels, we burn fuel in the engine. Let's take a state-of-the-art diesel engine. The best current technology has to offer. Let’s be kind and assume it averages 70mpg (Imperial). That means we need to put 2.5MJ[ii] ?into the engine to get 0.7MJ out, because engines unfortunately produce more heat than power. We also need to refine the fuel before we can burn it. Factoring that in that process[iii] , it turns out we need to consume nearly 3MJ for every mile we drive. That’s the energy equivalent of three Mars bars every mile[iv]

A petrol car is slightly worse, at around 3.7MJ/mile. That’s one of the main reasons why cars are expensive to run. It’s why, here in the United Kingdom, we spend over ￡50bn?every year?on petrol and diesel[v] ?- over 76% of which goes to waste as heat and pollution. I guess we somehow became inured to it.

While we’ve been happily burning fuel in cars for over a hundred years, it turns out this isn’t such a great idea. The pollution from burning fuel kills people. The CO2?released from burning fossil fuels is killing the planet on which people live. So, what to do?

Some twenty years ago, Toyota figured they could improve on this. Instead of wasting all that energy, why not try recovering some of it when braking or going downhill? After billions of dollars of development, behold: the “self-charging” hybrid. 80 mpg! Which, if actually achieved, means it only wastes 70% of the energy you put in[vi] . It only needs 2.3 Mars bars per mile! Which I guess is progress.?

A plug-in hybrid (or "PHEV") is a sort-of halfway-house that improves on self-charging hybrid technology to give you the option of charging the battery directly. If you always charge it up (and never put fuel in), it's like an EV. If you never charge it up (and always run it on petrol), it's like a self-charging hybrid. So, unless you only ever drive short distances, it still pollutes the air. Albeit slightly less.

“What about hydrogen?” I hear you say. Cool, let’s try hydrogen. If we make the hydrogen from green electricity, there’s no CO2. Nice. And burning hydrogen produces only water. Let’s burn it in our engine! Slight flaw: burning hydrogen in air also produces harmful NOx. Yes, your school chemistry teacher lied to you. I’m sorry you had to find out from me.

Maybe we could clean up the NOx with a catalytic converter? We know they work. Let’s go for it. Unfortunately, by the time we produce hydrogen by electrolysing water (70% efficient[vii] ) and transport it to the car (74% efficient[viii] ), we’ve now thrown away even more energy. We’re now at nearly 5 Mars bars per mile. Double the energy! This could get?expensive…

Maybe an engine wasn’t such a good idea after all. They’re complicated and inefficient. They go "brumm..." Seeing as we’re using hydrogen, why not use a fuel cell? They’re quiet and clean – no NOx, just lovely, pure distilled water out of the exhaust. The hydrogen fuel-cell car is the future!

We’ll need an electric motor (90% efficient), DC/AC inverter (90%), battery charger (95%) and a fuel cell (50%[ix] ). Use the hydrogen electrolysis and transport system from before and… darn. We’re now at 3.7 Mars bars per mile. It’s certainly better than burning hydrogen. But we’re wasting 81% of the energy we put in, which is?worse?than diesel (and no better than petrol). And we somehow need to pay for all those renewable energy sources, electrolysers and filling stations. I wish the hydrogen fans all the best, but I do wonder where the money is going to come from.

It’s a tricky one.

…BREAKING NEWS FROM THE PETROCHEMICAL INDUSTRY…

Synfuels! Never mind all this hydrogen car rubbish: we can take the hydrogen at source and make synthetic liquid fuel for you. You can buy it from us and burn it in your existing car. No need to change anything! Zero CO2!??[Editors note: best not to mention the bit about air pollution.]

Here’s the flaw: making synthetic fuel is energy intensive. Not only are we going to throw away 72% of the energy in burning the fuel in our noisy, inefficient, beloved engine – we’re also going to throw away 56% of the energy in making the fuel[x] . We’re now approaching?six?Mars bars per mile! Now, if I was in the business of selling fuels, this might seem like a really neat idea. However, I’m the one buying the fuel and frankly, it’s a terrible sales pitch. Go green! Buy our fuel! Pay double! Hmm.

Is that really the best we can do? Thankfully, there is another option on the table.

Let’s take all the best bits form the above: replace the inefficient engine with an efficient electric motor, but cut out all the intermediate steps. Put the renewable electricity straight into a battery. Call it an “electric vehicle”. Sure, there is inefficiency in the battery charging and electricity transmission. Let’s go with 4 miles/kWh. For every single mile, that means we have to put in 1MJ of energy.?

Shout out for the cyclists: while this is an article about cars, I should point out that cycling beats this energy consumption by a factor of ten. You can literally cycle for 10 miles on a Mars bar! ??

Compare that with the 2.9MJ/mile we’re currently paying for with our diesel or petrol car. Or 2.3MJ/mile with a self-charging hybrid. Or 3.7MJ/mile for a hydrogen fuel cell car. The EV needs less than?one third?of the energy of a hydrogen fuel-cell car, less than?half?that of self-charging hybrid.

Remember that ￡50bn/year we’re currently paying for fuel in the UK? How about ￡20bn/year for electricity instead[xi] ? ￡30bn/year saved!

That’s a mind-boggling amount of money and is hard to visualise. So, I’m just going to leave this here.

Reality check: the savings aren't going to stay at ￡30bn/year. Let’s reckon on the electricity cost eventually going up to ￡45bn[xii] ?(because taxes, apparently, are inevitable and the British Chancellor will still want their ￡28bn). Even with the same tax revenue, electric transport would save the country ￡5bn every year - purely through efficiency alone. With significantly reduced CO2?emissions now – and the potential to reach zero eventually. Oh, and zero tailpipe emissions. Did I mention it’s cheaper?

Ah, but! What about the cost of all those chargepoints? True, it’ll cost something like ￡25bn to build out the extra infrastructure. Let’s be pessimistic: this is the UK after all. Call it ￡50bn. Shiny new chargepoints everywhere!! The payback for this investment is 10 years (at worst). After that,?everybody?benefits…

The transition to EVs will happen.

Efficiency wins every time.

Resistance is futile.

[i] ?https://www.dora.lib4ri.ch/empa/islandora/object/empa%3A20269/datastream/PDF/H?nggi-2019-A_review_of_synthetic_fuels-%28published_version%29.pdf ??0.7MJ/mi - equivalent to average EV consumption 3.5mi/kWh. 69% efficiency: 3.6 * 0.69 / 3.5 = 0.7MJ/mi.

[ii] ?https://en.wikipedia.org/wiki/Energy_density#In_chemical_reactions_(oxidation) ?Diesel = 38.6MJ/l: 70mpg = 38.6* 4.54 / 70 = 2.5MJ/mi?

[iii] ?https://www.osti.gov/biblio/961225-allocation-energy-use-petroleum-refineries-petroleum-products-implications-life-cycle-energy-use-emission-inventory-petroleum-transportation-fuels ?approx. 0.19MJ energy consumed per MJ of petrol at pump, 0.18MJ diesel.

[iv] ?https://en.wikipedia.org/wiki/Mars_(chocolate_bar) ?1 Mars bar = 1MJ

[v] ?https://obr.uk/forecasts-in-depth/tax-by-tax-spend-by-spend/fuel-duties/ ?￡28bn revenue @57.95p/l = 48.3bn litres ~= ￡50bn GB annual fuel expenditure

[vi] ?https://en.wikipedia.org/wiki/Energy_density#In_chemical_reactions_(oxidation) ?Petrol = 34.2MJ/l: 80mpg = 34.2* 4.54 / 80 = 1.94MJ/mi

[vii] ?https://www.pv-magazine.com/2018/04/09/hydrogen-dont-give-up/ ?Electrolysis efficiency 70%

[viii] ?https://afdc.energy.gov/files/pdfs/hyd_economy_bossel_eliasson.pdf ??Assume 40MJ/kg for liquefaction, 113MJ/kg specific H2 energy giving 113 / (113 + 40) = 74%

[ix] ?https://www.nrel.gov/docs/fy19osti/73011.pdf ?Fuel cell efficiency 57% peak. Real-world consumption data shows 50mi/kg (or 2.26MJ/mi), equivalent to fuel cell efficiency 42%. However, fuel cell technology is still improving so call it 50%.

[x] ?https://www.dora.lib4ri.ch/empa/islandora/object/empa%3A20269/datastream/PDF/H?nggi-2019-A_review_of_synthetic_fuels-%28published_version%29.pdf ?range from 4.6-6.4MJ/mi. Mid-range value (5.5MJ/mi) is close to my analysis assuming fuel synthesis efficiency 63% (5.7MJ/mi)?

[xi] ?https://www.nationalgrideso.com/document/199871/download ?Energy consumed by full fleet electrification 100TWh @ 20p/kWh = ￡20bn

[xii] ?Assume ￡20bn electricity cost includes ￡3bn in tax. Assume treasury want ￡28bn, so add ￡25bn to make up shortfall?