Sunday, 28 August 2016

synthetic fuels vs electric battery cars

If carbon neutral synthetic fuels can be produced cheaply enough, are the considerable costs of turning our transport system over to battery powered one worth it? And as batteries are powered by the grid,  this isn't going to be carbon neural  for the foreseeable future.

There are many methods for producing synthetic fuels, I think those using sea water look most interesting, so we'll use those as an example.

"The U.S. Navy estimates that 100 megawatts of electricity can produce 41,000 gallons of jet fuel per day and shipboard production from nuclear power would cost about $6 per gallon."

"In 2012, Willauer estimated that jet fuel could be synthesized from seawater in quantities up to 100,000 US gal (380,000 L) per day, at a cost of three to six U.S. dollars per gallon."

So, that basically means that the wholesale electricity cost of 41,000 US gallons (155201L) is 2400mw/h x £40(today's wholesale per mw/h) = 61p per Litre.

Internal combustion engine(ICE) cars are now edging towards achieving 100 mpg. There are new engine technologies hoping to improve this, such as

Hybridisation using batteries, flywheels or compressed gas can improve efficiency still further by regeneration energy lost under braking.

Point is, if we can get the cost of a 100 mile journey using ICEs to £2.77 (61x4.55) that is also carbon neutral, is it worth pursuing an expensive transition to battery only powered cars? Where a 100 mile journey, which is not CO2 neutral, costs around 30kw/h at 12p per kw(retail), adding up to £3.60

Of course I am not comparing like for like ie wholesale vs retail. But then a large manufacturer of synthetic fuels would probably have their own plant or negotiate low prices. Maybe it would be worth building a dedicated nuclear power plant for the job?

The UK currently uses 45 billion litres of petrol/diesel every year. If continuing efficiency can half this we'd need  around 45gw of extra electric generation to make the equivalent in synfuel. 

That's roughly the equivalent of 12 Hinkley Point C, to end our dependency on petrol and diesel imports, and reducing net CO2 emissions by 120 million tonnes per year.  

Hybrid cars may be a good idea. What may not be a good idea is to replace the internal combustion engine and all the infrastructure created for it, with a technology that is more expensive,  less convenient,  and will require an massive and expensive upgrade in infrastructure. 


Mark Wadsworth said...

Agreed. I said much the same to Her Indoors earlier (by coincidence).

Bayard said...

Another point is that making synfuel (useful neologism, BTW) can soak up excess capacity from solar and wind when it's sunny and windy. Assuming that otherwise this energy would go to waste/not be captured in the first place, it would be efficient to then burn the synfuel on cold, cloudy, windless days.

My view on hybrids is that the only hybrid really worth building is the series hybrid layout that has been used on the railways since the 1950's: it gets rid of the gearbox, drivetrain and differential(s) allows a constantly variable transmission and full torque from standstill, as well as full regenerative braking.

Striebs said...

Electrolysis of seawater using electricity from nuclear involves an intermediate steam cycle turbine which is not very efficient .

Alternatively , one could use a high temperature nuclear reactor to provide process heat at 750c+ to partially oxydise a carbon based feedstock (e.g. rubbish) using steam as an oxydising agent to produce a synthesis gas of carbon monoxide and hydrogen :-
- C2 + 2H2O -> 2CO + 2H2

The synthesis gas could be used to fuel a compatible gas turbine or converted to methane using a nickel catalyst or less efficiently to waxes and syncrude using fisher tropsh .

Just be nice to be able to get away from the intermediate steam cycle .

As a bridge , we could fuel our commercial vehicle fleet with compressed natural gas if domestic shale gas ever gets off the ground and reduce diesel imports and particulates significantly .

60 years ago , France proved that wide scale nuclear can be implemented in a hurry . Maybe Toshiba will sell BNFL Westinghouse back to us ?

In order that Britain can formulates an energy policy , there needs to be an HONEST assessment of the role of renewables in the context of a tiny landmass with 70 million people - which may be a disappointment to some .

benj said...

@ Striebs
"Electrolysis of seawater using electricity from nuclear involves an intermediate steam cycle turbine which is not very efficient "

It's not "electrolysis" in the way you perhaps mean.

Anything generating electricity from a steam cycle isn't efficient, so what? There's plenty of Uranium and Thorium for that not to be a problem. And fuel costs hardly matter for nuclear.

They are removing carbonic acid from the sea using a membrane(which is in balance with Co2 levels in the air. Hence this process is neutral and stops ocean acidification as a bonus!) and taking the CO2 from there, from which they also get H2 in the process).

They can combine these in anyway they want to produce any kind of fuel they want.

Yes, 61p per litre is more expensive(at the moment) than untaxed petrol or diesel. But that's not the point is it? It that less costly than battery operated vehicles?

It looks as though that if they can scale something like this up, it will be.

By that time though, we may have already gone too far down the wrong path to turn back.

Physiocrat said...

I was sceptical about electric cars but they are increasingly popular here in Sweden. The up-front cost is high but evident advantages to the consumer are

(1) Less noise.
(2) Less pollution in the street.
(3) Quieter and smoother to travel in.
(4) Reduced maintenance costs and wear and tear.
(5) Promotes energy-efficient driving at optimum speed.
(6) The marginal cost of each additional journey is low.

benj said...


How many BEVs/plug in hybrids would be sold in the UK if there was no subsidies, congestion charge exemptions, zero car tax, and high taxes on petrol/diesel?

Not many, eh?

The points you raise as benefits are marginal or arguably wrong in a comparison to modern engines.

If fuel today was priced at 61p litre, how many people would pay full list price for a BEV, the cost of installing a charger at home (if you have your own drive),the inconvenience and "range anxiety" of batteries, whose performance drops with use, leading to a very costly replacement sooner or later?

They only do in places like the States because they are rich enough to show off their green credentials. If there wasn't a problem with CO2 emissions, they wouldn't bother.

If you have low cost fuel and very efficient(and clean) engines, battery only vehicles makes no economic sense. And seeing as most electricity comes from burning fossil fuels (Sweden excepted), then they aren't that green either.

What we want in society is instant, dense, reliable energy sources. That enables efficiency, progress and growth. Is it any wonder the neo-luddites are so keen on foisting the very opposite upon us?

Physiocrat said...


I was as sceptical as you but some friends bought a plug-in 100% electric (Toyota Leaf - ugly looking beast) and I changed my mind after riding in it.

Range anxiety is not an issue for regular journeys with known charging points. Maintenance costs are low, as with all electric traction. There fewer moving parts to be attended to.

Bayard said...

Electric traction is the way forward, but it needs to be the way forward without subsidies, direct or indirect. Plug-in series hybrid removes "range anxiety" whilst giving you all the benefits Phys lists:
(1) Less noise. - smaller engine running at optimum constant speed. The power of an IC engine is dictated by power requirements on acceleration, which type of transient demand would be handled by the battery.
(2) Less pollution in the street.- the IC engine can be switched off in town
(3) Quieter and smoother to travel in. - constant speed and smaller size = less noise, final drive is electric so smooth
(4) Reduced maintenance costs and wear and tear. - IC engines wear less at constant speed.
(5) Promotes energy-efficient driving at optimum speed. - I don't understand this. Electric motors have the same efficiency at any speed.
(6) The marginal cost of each additional journey is low. - also true because you'd be getting 100MPG or better.

Physiocrat said...

You tend to drive efficiently in an electric car as you can see your charge going down fast if you push the speed up. You can tell by the wind noise. There is a big difference between 60 and 50 mph. You also tend to coast downhill re-charge. Braking energy is regenerated.

Bayard said...

"You tend to drive efficiently in an electric car as you can see your charge going down fast if you push the speed up."

That's not really driving more efficiently, that's driving more slowly, which uses less fuel whatever fuel that is, and whatever sort of car you drive, you tend to go downhill with your foot on the brake. Does it make much difference to your driving style if it's a friction brake or an electric brake? I suppose you can't coast down hill with your foot on the clutch, because there isn't a clutch on an electrically driven vehicle.

Physiocrat said...

I have travelled quite a lot in electric cars. Their appeal is not about saving the world. They are quiet, smooth and comfortable. Once you had owned one, you might not want to go back to having a vehicle with an internal combustion engine.

You tend to keep your speed down as the noise rises so noticeably above 60 mph and your charge meter starts to go down fast. You go further for the energy you consume. Resistance is proportional to the square of the vehicle's speed.

benj said...


"Electric traction is the way forward, but it needs to be the way forward without subsidies, direct or indirect."

While there are market distortions, not least from very powerful lobbyists, it's very hard to say what is the way forward.

The point of the OP was, if carbon neutral fuel costed 61p per litre, would BEVs make any economic sense? There's some proper Greenwashing going on, which provides all sorts of rent seeking opportunities for canny corporations.

Bayard said...

"Resistance is proportional to the square of the vehicle's speed."

Being an engineer, I was aware of that. Any vehicle starts to use a lot more fuel above 60 mph. Perhaps more responsive and accurate fuel gauges in IC cars would be more effective in getting us to save fuel than Green propaganda.

"it's very hard to say what is the way forward."

I meant that electric traction is the way forward from an engineering point of view. As Phys says about electric cars "Their appeal is not about saving the world." If it wasn't for Big Green, hybrids would first have appeared as luxury sports cars, sold on their performance, not their fuel economy. Then, as time went on, less and less expensive versions would appear on the market until eventually they were the majority design.

Striebs said...

So electric cars are popular in Sweden .

Do they use the batteries for heating of the cabin air ?

If so , any idea how many kW it takes to maintain a comfortable temperature when it is -40c outside ?

What better way to go virtue signalling than take a new Tesla on the beaver patrol ?

Physiocrat said...

In the areas of Sweden where most people live, winter temperatures are typically between +5 and -5 C. The Stockholm area might have about four weeks of -10 to -15 in a cold winter. Almost nobody lives where it gets down to -40 and they are more likely to use a motor sledge than a car. For five months of the year, keeping cool inside the car is as much of a requirement.

The popular Toyota Leaf uses this heating system, featuring a heat pump which works on both heating and cooling cycles.