Wednesday, February 14, 2007

33 Million cars - a Flash in the Pan!

The Independent yesterday carried a front page banner that there are 33 million cars on the U.K. roads, which includes a rise of 7 million of them in ten years. This is indeed a staggering statistic since this fleet of road traffic presently gets through fuel to the equivalent of around 44 million tonnes of oil each year. The article also points out that 20% of our CO2 emissions are from traffic. That must be just from cars, since around 30% of the nation's entire energy budget is accounted for by the end-use of fuel (planes included), much of the rest of that "energy" coming from gas and coal. Conventional car-engines use fuel very inefficiently, deriving only around 14% of the fuel's intrinsic energy worth in terms of road miles. Burning gas or coal in power stations is done at around 35% efficiency, which is still woefully low, but better than is manged by cars etc. More efficient cars have been devised, e.g. the generation of "hybrids" which produce electricity from revolutions on the road, and use that to power the vehicle at low speeds "in town", a combination which gets 42% of the fuel energy back in the form of tank-to-wheel efficiency. Hence the transport-induced CO2 emissions could be cut by means of vehicles based on this kind of technology. Likewise, combined-cycle coal fired power stations can run at much greater efficiencies than conventional plants, and can additionally produce synthetic oil too.
Now, this gets me onto the salient point of this issue. We seem to be bombarded with information about growth in the developing world (e.g. China and India), how many cars there will be by the year 2050 and so on, based on projected estimates of a linear escalation of trends and numbers. However, to use my analogy about the growth of bacteria, the steeply rising portion of the S-shaped curve that describes this process mathematically only continues to rise while there is sufficient fuel (food) to support such proliferation. In the human case, the fuel is oil (used to run transport and to grow food). We are on the one hand presented with all kinds of projections "to 2050" (i.e. about 43 years hence) and yet there are only sufficient oil reserves claimed with confidence (i.e. about one trillion, or one thousand billion, barrels left) to last for about another 30 years, and that is if we could extract the whole lot, when it is not certain than we can. Oil wells cannot simply be drained to bottom, as extracting oil becomes increasingly difficult, energy intensive and expensive as the well reserve falls. The quality of the oil that is pumped-up falls too, and the material becomes steadily heavier and contaminated with sulphur and other compounds that it needs to be cleaned from before it can be refined into a useful fuel. It is generally agreed that we are close to the point of maximum oil production (production has fallen in Norway now, I notice, pulling that country down into fifth place among the giants of oil exporting nations) and so supply of conventional crude oil will fall inexorably from here on in.
Some of that inevitable shortfall can be offset by building coal-fired combined cycle power plants (which make both electricity and oil), and yet none have been installed as yet, certainly not in the U.K. There are various predictions made about biofuels, which my calculations here show to be unsatisfactory as a means of replacing the current massive volumes of fuel that we rely on, and at best we might produce about 10% and probably a lot less than that, unless we are willing to stop growing food. Of course that would be madness, as in an oil poor world all nations will need to be largely food-sufficient within their own borders. The hydrogen economy looks set to be a damp squib, since the scale of infrastructure and problems in storing and distributing the gas mainly render it unsuitable as a serious contender for an energy carrier (which it is - not a fuel per se).
Hence, 33 million cars on the road in the U.K. is the least of our worries. Than number will fall unequivocally as the means to fuel them runs out. Even if we can extract one third of the remaining one trillion barrel oil reserve at near present output, that is just 10 years worth, with demand breathing harder all the time, and hence the level of car use will fall dramatically within a decade. There may be more fuel made available from "unconventional" sources, but it will become increasingly costly. It must do. Logically too, society will accordingly begin to localise, and it is this eventuality we should be focussing our efforts and plans to meeting. The massive world population of cars is just a flash in the pan; we must try to ensure that the human population will not fail too... and die-off like bacteria!


Anonymous said...

Thank you for your analysis, but your efforts to be pessimistic don't seem to quite convince my maybe so naive view about things. I must admit my total ignorance about anything that has to do with technology, but like every human being I am a bit concerned about the future of oil. Reading your article where you seem to label as unrealistic the future of biofuels etc as a replacement for oil, I asked myself if all I've read in the past week or so has been just plain wrong. Could you double check for me and let me know? the first thing is about cars. I have two links:

and another one relating to even more possible future developments in car technology

I've seen that you are quite critical about the production of bioethanol from crops that could be used for food, how about the production of biodiesel and bioethanol from algae and agricultural cellulosic waste?
What is your opinion when you come across data like this

quite encouraging to be honest, maybe too good to be true (you could answer freely, maybe better trying to apport changes where appropriate, especially to the yields grid)?

Considering that even half of that is true and in view of the possibilities in terms of low consumptions vehicles I've just shown you (and lifestyle), would you change your opinion on this matter and why?

Thank you very much

Professor Chris Rhodes said...

My "efforts" are intended to find the truth, not necessarily to be pessimistic; however, the prognosis based on straighforward calculations is not very encouraging for biofuels.

I have clicked-on all these links you refer to and maybe they have been removed from Wikipedia, but the procedure does not lead to any articles that I can read.

If you can supply me with some other links I will be pleased to analyse the information and I will devote a posting to that analysis, as you raise some important points here.

To be going on with, I make the following comments:

(1) if the entire corn crop of the US was converted into bioethanol the present levels of transportation fuels could just about be met... but no food of course, which would really kick the world market for corn since the US is the breadbasket of the world.

(2) Making biofuels from e.g. wheat grass (agricultural cellulosic waste) requires a technology that is not yet fully developed, and I worked put for the UK that it probably wouldn't satisfy more than around 10% of current consumption.

(3) For sure, if more efficient cars e.g. hybrid "Prius" say, or the new Volks Wagon high-efficiency diesel car were substituted for the current generation which gives around 14% tank-to-wheel efficiency, then that could be raised to about 42% and so the fuel demand (arithmetically at least) could be thereby reduced to one third of current quantities. So that would e.g. consume "only" one third the entire US corn crop!

I am not a pessimist by nature; I have worked out all figures fully for the UK (I always show my workings in these postings rather than just plucking numbers out of thin air, or raising objections to scientific arguments just because I don't like the conclusions one is drawn to). If we are to come anywhere close to providing "alternative fuel" to substitute the enormous amount we use now coal-liquefaction is probably the only means to do so - not biofuels. Biofuels might give us 20% using agricultural waste etc. (Algae is also an untried technology on the full scale), and logic suggests to me that the only way to meet the inevitable huge gulf (no pun intended) between usage and supply is to use a lot less, and that means curtailing transportation significantly, unpalatable though that is.

If you can provide some alternative links to those articles I shall be pleased to look at any figures in detail.


Chris Rhodes.

Anonymous said...

thank you again for your reply. I try and repost mine again. As I have already explained I'm no scientist so my opinion totally relies on what I read on the net. It seems to me strange those links don't work, I have an additional link,
I would start with an imprecision in your post:
"For sure, if more efficient cars e.g. hybrid "Prius" say, or the new Volks Wagon high-efficiency diesel car were substituted for the current generation which gives around 14% tank-to-wheel efficiency, then that could be raised to about 42% and so the fuel demand (arithmetically at least) could be thereby reduced to one third of current quantities"
In the links I've sent you the new generation of vehicles are supposed to function with a fifth at least of the fuel currently used, not just a third.
Then, there's what seems to me as
a contradiction
" So that would e.g. consume "only" one third the entire US corn crop!"

well allow me to say, you have reached your goal already, you are running on biofuels and you got 2/3 of the crop to spare. Then noone really eats corn, the majority of the US corn production is used as fodder for cattle and corn after distillation can be recycled as fodder too.
A third statement sounds a bit incomplete
"Making biofuels from e.g. wheat grass (agricultural cellulosic waste) requires a technology that is not yet fully developed, and I worked put for the UK that it probably wouldn't satisfy more than around 10% of current consumption."
according to your estimates, how much is 10% in terms of litres of fuel?
So the point is, in the initial thread you mentioned that in the UK transport fuel consumption is about "44 million tonnes of oil each year"
can we say 51 billion litres of fuel each year? well let's bring that down to a fifth with new generation vehicles, it's 10 billion odd litres of fuel a year. With these new figures, have you changed your idea about biofuel potential? Why?

Professor Chris Rhodes said...

Dear Anonymous,

there are a few more points. Firstly, it is not that the links don't work, but there is no information in those "Wikipedia" files when one does get to them. Try clicking onto them for yourself and see what I mean.

I have read several articles recently which also conclude that there is not enough land to produce the US fuel ration using bioethanol without compromising food production. In "Chemistry World" this month, it is reckoned that just 12% of the fuel demand could be provided by turning the entire US corn crop into ethanol. I think you would need to plant "all" the US arable acreage with corn to produce enough to replace oil entirely.

That brings us onto the issue of fuel efficiency. I have looked on Google and I can't find anything that suggests that fuel could be used five times as efficiently. The 42% tank-to-wheel figure that I used in my sums is the most optimistic that I can find. That is for a deisel-hybrid.

Can you provide me with a reference to the type of vehicle you have read about?

I agree, that more efficient cars could reduce demand considerably and that might make a big difference to how much fuel we do need to provide from alternative means. However, they are bound to be expensive and this will hold-back production of them, at least initially.

Corn in fact underpins much of food production in the US. For example High Fructose Corn Syrup which is included in many different kinds of foods, along with other uses. The US corn export is also a substantial proportion of the world corn market, which would be hit if that amount were instead turned over to ethanol production.

I was very interested in your last "link" about making biofuel from algae, but I wonder just how much water would be required to fill those "ponds" to grow it in? Quite a lot probably.

As we are having a dialogue, who are you incidentally? I always like to know who I'm talking to.

The intention of this blog is to explore possibilities for future energy provision, and I will do some more sums from first-principles on all these issues when I have some more data.



Anonymous said...

I'm sorry if I didn't introduce myself. My name is Marco, I'm

Italian and I live in Belgium. I read quite a few articles about

biofuels, and while I'm not a biofuel enthusiast myself, I have

to say, I think that that can be the one of the only options

remaining until a major technological revolution can take place.

To put it simply, while it's hard work to collect and extract

ethanol or diesel from waste plants, what other choice is there

for a renewable source? and rereading again some articles I sort

of had a second thought about biofuels.
Other stuff to read:


I'm quite surprised those links don't work, I've tried to copy

and paste them into my browser and they show the correct page

each time. I can copy and paste the grid here
Crop kg oil/ha litres oil/ha lbs oil/acre US gal/acre
... ... ... ... ...
rapeseed 1000 1190 893 127
olives 1019 1212 910 129
castor beans 1188 1413 1061 151
pecan nuts 1505 1791 1344 191
jojoba 1528 1818 1365 194
jatropha 1590 1892 1420 202
macadamia nuts 1887 2246 1685 240
brazil nuts 2010 2392 1795 255
avocado 2217 2638 1980 282
coconut 2260 2689 2018 287
chinese tallow 3950 4700 3500 500
oil palm 5000 5950 4465 635
algae 80000 95000 70000 10000

This is from
As you can see the estimates for algae are incredible, 95000

litres of oil per hectare per year. In some other sites they

mention algae as the origin of petroleum, and they suggest it

would be a good idea, instead of preying on million years old

fossil reserve, to grow new algae. I don't know where algae can

grow, and I know they suggest to use a desert, which seems a bit

unlikely, as you seem to suggest, as they would reauire a lot of

water even just to fight evaporation. have they ever tried with

the sea I ask myself? How about sewage systems, it seems they

can grow there too. There must be a way.
The second link

Yields of common crops associated with ethanol production
Crop litres ethanol/ha US gal/acre
Miscanthus 14031 1500
Switchgrass 10757 1150
Sweet Potatoes 10000 1069
Poplar Wood (hybrid) 9354 1000
Sweet Sorghum 8419 900
Sugar Beet 6679 714
Sugar Cane 6192 662
Cassava 3835 410
Corn (maize) 3461 370
Wheat 2591 277

the whole thing started when I came across an article about the

prototype of a car (VolksWagen 1L) that can run 100 km on a

litre of fuel (actually it outperformed, doing 100 km on 0.89l

of fuel).
Then I read about a second car, the Loremo, that can do 100 km

on 1,5l. They are planning to start producing it in 2009 (and

I'm planning to buy one), and they estimate the cost is gonna be

less than 11000€.
But what about the experiment done by GreenPeace with a Twingo, and
They could have done even better I guess (I'm not an engineer)

if they took off an extra 200 kg and they put a smaller engine

in, they could have got to a 50 km per litre car perhaps??
The idea which is behind all this is that it's necessary to use

different technologies for cars, transport and for living in

general. The Prius I've seen is a ton of metal at least, it's

basically a normal car that consumes a bit less.
The idea is that today whenever someone gets into a car and

drives off, in most cases with the car half empty, they travel

around in between a ton and a ton and a half of metal for no

reason at all, with aerodynamics sacrified to the looks of the

car, with an oversized engine that will only waste precious fuel

(I don't think I'm mistaken if I say on average a car will use 1

litre of petrol every 15 km).
New technologies can improve this situation. 33 million cars

travelling 16000 km per year (national average in Italy, it's

43km, 27 miles per day) and that can afford to do so consuming

an average of 1l of fuel every 50 km (note, I'm saying here 50

km, not 100 or 66 km as the Loremo), will only require 11

billion litres of fuel. Can this be achieved with biofuels? If

the answer is yes, well, we can be sure we will be driving in

the future without problems.
And I guess many other problems can be solved changing the

technology used in all activities.
Obviously if you start by saying current fuel demand and current

production you will always come to the same conclusion, that

it's impossible. But if you say I can produce this much with

biofuels and my new technology (transport, etc) can only require

this, you will see that 11 billion litres a year for car

transport (against the current 51 billion) is or seems to be a

figure that can be supported by biofuel production. Do you

agree? And apparently it can be done even by using agricultural

waste, so you wouldn't need to touch food crops at all.
I've read in the first links I gave you

If you can help me in this, maybe you can understand better what

they write, but it seems to me very promising and they mention

only agricultural waste here. A lot more could be done too.
Then for other things, I always ask myself why roads and cities

must stay brightly lit all throughout the night, talking about

waste, and a lot of other ideas that can be apported to consume

I'm no environmentalist to be honest, I support the idea of

nuclear energy but I think nuclear energy isn't renewable, but

still experimenting with nuclear energy (fusion, etc) is

important for technological advances. Of course if anything can

be done in a clean way, the better.
I recently read an article about a car that can run on water and


But that would be too good to be true. Let's keep it real for

the moment.

they mention "The yield of cellulose ethanol is more than 340

litres per tonne of fibre" well I don't know if the fibre is the

haystack in the picture. However, in the first link,

they suggest "More than half of the 40 million t of straw

harvested each year on German farms is simply ploughed back into

the soil, as there is currently no alternative commercial use

for this material"
40 million tonnes of straw, that's quite a lot if it's only

straw, and it's just waste material, nothing you use for food.

Suppose to liquify it as they suggest or make bioethanol with

it, according to that figure, you would and could get 40 million

tons x 340 litres = 13 billion 600 million litres of ethanol,

which is very good I reckon. Of course these are only estimates

and to keep it real we must think that private companies might

try and boost their numbers to keep investors happy. Yet when

you think that waste material is not only straw, and you can

grow algae to compensate using no land, well, it would be

interesting to see what they can get out of this. But for me the

key element is reduction of consumption, I was thinking about

the shell eco marathon,, they devised a

vehicle that could run 12 thousand miles per gallon on hydrogen.

I'd like to see an eco marathon every sunday on television

instead of F1, but done with cars that can be roadworthy. Some

of that technology could be used to do something.
And overpopulation is the problem above all that must be solved.

I don't know if you agree on the data there's on those links, I

certainly don't have the competence to disagree with them, but

altogether I think people won't have to give up cars or travel
in the future just as long as they can consume less

exploiting new technologies.

Professor Chris Rhodes said...

Hi Marco!

I think the idea of growing algae to produce biodiesel is by far the best bet, and I have just written an article about that (posted yesterday). I think that if the technology can be perfected to turn cellulose into ethanol, that might be very useful and some of that ethanol could be used to "trans-esterify" the algae "oil" into biodiesel. You'd need about 10% as much ethanol as oil to do that... roughly!
I did find the Eco-marathon link and those mile/per/litre figures are truly amazing! However, these are cars that carry a very low payload, are aerodynamically designed, and must have all kinds of features to get better mileage. I think the criterion is they have to do at least 15 mph over 10 miles, and then the value is scaled to a final miles/per litre figure. These wouldn't be useful vehicles for general use, and I think too that if they have to stop-start a lot, as in towns and cities, the efficiency would fall considerably. However, I agree that better designed engines and vehicles could make fuel use far more efficient.
There is the matter of how quickly any new technologies can be implemented. If all cars need to be switched-over to being hybrids, say, that will take time and a lot of money. If they can be used more or less as they are (or conversion to Diesel engines) that would cut time and costs.
Using e.g. hydrogen has many problems, not only making it on the large scale but in handling a very dangerous material, which takes a lot of energy to compress or liquefy, and which would need very heavy engineering to store it in vehicles under pressure (adding weight and losing efficiency) or using light carbon materials for the tank which would not survive well in a crash.
However, biodiesel could be distributed more or less using conventional pipelines and tankers, which would make the change-over much easier. So as far as I can see, the emphasis should be on making a large quantity of biodiesel from algae. Say one million tonnes, to really push the potential of this technology. Once proven (beyond the lab scale, that is) then I don't see why this approach shouldn't come on-line fairly quickly.
The only stopping-point I can see is that there are huge and complex political agendas over "oil", probably more than those of us who are not politicians can understand, concerning money and world-power, and I could envisage some resistance there.
But on all grounds that George Bush has given for bioethanol production, i.e. breaking dependence on imported oil and cutting CO2 (although he is less worried about that than we are in Europe), surely algae offer the best option - and there is no need to compromise food crops either, for consumption in various forms in the US or for export. Surely, everybody would be happy?!


Anonymous said...

Hello again,
I apologise for my English for a start, unfortunately sometimes I just keep writing and I translate Italian into English maybe not realising some words r constructs don't even exist.
Yes I totally agree on that, algae seem to be the best solution
So far. I've seen a blog,
Somehow I get the impression it's not as straightforward to extract oil from them and it's best to keep real, but I think and hope a solution will be found in the end. By the way I'm looking for a pet store where I can find some algae to grow just as an experiment and see for myself what they are like. Sure what I'd like to see totally out of curiosity (I'm not a researcher or anything, just a curious) is some fresh data. And possibly the best thing is to keep working on all possibilities at least at the beginning and then choose the best solution. But this is just common sense.
Yes I have heard about the dangers and difficulties of storing hydrogen so it's kind of puzzling why there is so much hype about hydrogen fuel cells in cars. A simple diesel engine can do wonders and it's a lot less complicate to manufacture.
I've read your new article on biodiesel from algae and I totally agree with it.

Professor Chris Rhodes said...

Hi Marco!

There is probably no holy grail! I too get the impression that there are problems in growing the algae and so on. But still, it looks very positive!

I'll read your link!