CO2 emissions per liter of fuel: petrol, diesel or LPG

What are the CO2 emissions depending on the fuel you use: gasoline, diesel (oil) or LPG? In kg of CO2 per liter of fuel

CO2 exhaust gas and water

This page is the practical application and summary of the page the alkane combustion equations, H2O and CO2

We invite the reader to read this page to know the precise method and combustion equations used. He may also ask questions about the forum energies, especially if these figures puzzled him (but this is only basic chemistry ...)

Recall the method

We start from the combustion equation to arrive at the following observation.

The mass of CO2 emissions from an alkane of formula CnH (2n + 2) is 44n and the water vapor emissions are 18 (n + 1). This water will eventually condense a few days later, 2 weeks on average, the CO2 has a lifespan in the Earth's atmosphere of about 120 years.

With n index of the hydrocarbon (family of alkanesSee their classification).

We have studied the case of the most common fuel 3 and natural gas:

  • Gasoline
  • Diesel or fuel oil
  • LPG or LPG
  • Methane

One liter of gasoline that weighs 0,74 kg emits 2,3 kg of CO2 and 1 kg of water

Chemically, gasoline can be assimilated to pure octane, i.e. n = 8. In fact, there are dozens of different molecules in gasoline, including additives, but it can be likened to octane.

  • The molar mass of octane is 12 * 8 + 1 * (2 * 8 + 2) = 114 grams / mole
  • The mass of CO2 released per mole of octane burned is 44 * 8 = 352 g
  • The mass of H2O water released per mole of octane burned is 18 (8 + 1) = 162 g
  • The ratio of gasoline consumption to CO2 emissions is 352/114 = 3,09 and that for water 162/114 = 1,42

Knowing that the density of gasoline is 0,74 kg / l and that 1 gram of burnt gasoline releases 3,09 grams of CO2 and 1,42 grams of water, it comes to: 0,74 * 3,09, 2.28 = 2 kg of CO0,74 per liter of gasoline burned and 1,42 * 1,05 = XNUMX kg of water.

In the end, we have emissions of 2,3 kg of CO2 and 1 L of water per liter of gasoline burned. The CO2 + H20 to fuel mass ratio is 3,3 / 0,74 = 4,46!

A liter of diesel (or diesel or fuel oil) that weighs 0,85 kg rejects 2,6 kg of CO2 and 1,15 kg of water

Chemically, diesel, diesel oil or heating oil can be assimilated to pure hexadecane, ie n = 16.

  • The molar mass of hexadecane is 12 * 16 + 1 * (2 * 16 + 2) = 226 grams / mole.
  • The mass of CO2 released per mole of hexadecane consumed is 44 * 16 = 704 g
  • The mass of water H2O rejected per mole of hexadecane burnt is 18 (16 + 1) = 306 g
  • The ratio of diesel consumption to CO2 emissions is 704/226 = 3,16 and that of water is 306/226 = 1,35
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Knowing that the density of diesel is 0,85 kg / l and that 1 gram of burnt diesel rejects 3,16 grams of CO2 and 1,35 grams of water, it comes to: 0,85 * 3,16 = 2,67 , 2 kg of CO0,85 per liter of Diesel burned and 1,35 * 1,15 = XNUMX kg of water.

In the end, we have emissions of 2,7 kg of CO2 per liter of diesel, gas oil or heating oil burned and 1,15 kg of water. The CO2 + H20 to fuel mass ratio is 3,85 / 0,85 = 4,53!

LPG: 1,7 kg of CO2 per liter

LPG is a mixture of butane and propane, ie C4H10 and C3H8. Depending on the tanker, the proportion varies from 40 to 60 of one or other of the components.

We will retain an average value of 50 / 50 or 3,5 n = medium.

The mass of CO2 released per mole of octane consumed is: 44 * 3,5 = 154 g.
The LPG consumption ratio on CO2 releases is 154 / 51 = 3,02

Knowing that the density of LPG 50/50 is about 0.55 kg / l at 15 ° C and that 1 gram of burnt LPG releases 3,02 grams of CO2, it comes: 0.55 * 3,02 = 1.66 kg of CO2 per liter of LPG burned.

Or 1,7 kg of CO2 per liter of LPG, the mass ratio of CO2 to mass of fuel is 1,66 / 0.55 = 3! LPG is therefore still a major emitter of CO2!

WARNING this value is not directly comparable with that of gasoline because the energy supplied by a liter of LPG is less than that of gasoline or diesel fuel. Indeed; an LPG car will consume 25 to 30% more than gasoline per 100km, which is perfectly logical since LPG weighs 25 to 30% less than gasoline.
With gases, it is important to always think in mass and not in volume…. Even for liquefied gases!

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Releases of CO2 for 100 km by car Essence or Diesel?

Let's move on to practice: how much does your petrol car reject? How much does your Diesel car reject?

  • Petrol car
      1. : if your petrol car consumes 6,0L / 100 km then it rejects 6,0 * 2,3 =

    13,8 kg of CO2 for 100 km is 138 g / km

  • Diesel car
      1. : if your diesel car consumes 5,0L / 100 km then it rejects 5,0 * 2,6 =

    13 kg of CO2 for 100 km is 130 g / km

We use here real numbers, not the idealistic figures from car catalogs that no one ever actually achieves! It is false and untrue to claim that a Diesel vehicle pollutes more than a gasoline vehicle, on the contrary the diesel engine is advantageous for limiting CO2 emissions and the greenhouse effect because its efficiency is better. In addition, it should be noted that a Diesel vehicle has a longer lifespan which must be taken into account in the pollution calculation! The longer you keep a vehicle, the less it will pollute because of its manufacturing energy.

Indeed; it is estimated thatit takes between 100 and 000 km to make the purchase of a new vehicle profitable to replace an old one that is still running! It is the calculation of thegray energy of making a car.

Discharges of CO2 per kilogram of fuel burned

The differences are much less obvious when we speak in kg of fuel, so we get:

    1. Gasoline: 2,28 / 0,74 = 3,08 kg CO2 / kg of gasoline (we find the value: 3,09)
    1. Diesel: 2,67 / 0,85 = 3,14 kg CO2 / kg diesel (we find the value: 3,16)
    1. LPG: 1,66 / 0,55 = 3,02 kg CO2 / kg LPG (we find the value: 3,02)

The more a fuel has a number of alkane (n), the more it will reject CO2 per kg… logical!

The cleanest fossil fuel is natural gas CH4, methane, which will reject it:

The mass of CO2 released per mole of octane consumed is: 44 * 1 = 44 g.
The ratio of methane consumption to CO2 releases is 44 / 16 = 2,75 g

1 kg of methane releases 2,75 kg of CO2! And, sorry for the defenders of "clean" gas, but we will not find better as a hydrocarbon!

It should also be noted that each mole of methane will also release 36 grams of water (18 * (n + 1) grams of water per mole) ... ie 2,25 kg of water per kg of natural gas burned!

For each mole of Diesel the value of water produced is 18 * 17 = 306 g / mole or 306/226 = 1,35 kg of water per kg of Diesel or 1,35 * 0.85 = 1,15 L of water by L of Diesel! As much water put, in fact it is synthetic water that was not in nature before, in the "climate cycle" is perhaps not so negligible!

Conclusion: our emissions are heavy, very heavy, and heavier than the fuels themselves!

As you can see, for CO2 when we speak in kg of fossil energy, this plays out like a “pocket handkerchief” and in the end what matters a lot in CO2 emissions are the yields of the devices that burn these fuels. Thus a Diesel engine will pollute less CO2 than a gasoline engine because its efficiency is better by design!

The difference in CO2 when switching from Diesel to methane is only 2,75 / 3,16 = 0,87 ... or 13% less, so it is certainly not natural gas that will save the climate ( yet it is sold by some as such ... must be said that "natural" gas can lead to confusion)!

And finally, the combustion of fossil fuels depletes the atmosphere in oxygen (hence the excess mass of waste!) While enriching it with water!

And the excess water introduced into the "climate system" by the combustion of fossil fuels is perhaps not so trivial for the climate and climate change!

To go further, a few pages on synthetic fuels:

34 comments on “CO2 emissions per liter of fuel: petrol, diesel or LPG”

  1. I am happy to read this page which highlights what has been for me for a long time.
    But beyond that, we are not talking about the transformation of crude oil into gasoline, a more complex process than for diesel.
    And if we want to tackle diesel which pollutes then let's see on the side of ships ... when will a real carbon tax on commercial transport which would rebalance trade and boost local production. But that would not do the business of multinationals hence their lobbies and our pseudo green people who see no further than the tip of their nose ... or their corrupt wallets.
    And if we were to switch vehicles to electric, how many EPR plants will it take to power all of these cars?
    Besides, who manufactures batteries… German and Chinese and in France… Bolloré? CQFD. Not to mention recycling… in progress?
    In short, all this is nothing but shouting about our government, which bailed out the state coffers on our backs ... as always since the dawn of time ... we cut off heads at one time ...

    1. Some elements of answer to Martineaud, whose answer contains unfortunately several received ideas:

      1 - Normally, we do not transform the crude, we refine it, that is to say we separate the main constituents. Obtaining gasoline is not a priori easier than obtaining diesel, nor more difficult, it all depends on the initial composition of the crude, which varies from one oil field to another. If the crude is particularly light, it will not contain gas oil - this is typically the case with bedrock oil in the United States (so misnamed "shale oil" by the media). The heavier the crude oil, the less gasoline it will contain and the more heavy fractions it will contain, such as fuel oil (or diesel: it's the same product), even heavy fuel oil - and the general trend of crude production in the world is that of a slow and progressive increase in the crude extracted.
      When the crude is really too heavy with regard to uses (the extreme cases being extra-heavy fuel oils, extracted in particular in Venezuela, and bitumens, typically extracted in Alberta, Canada), the excessively heavy fractions of this crude must be (there, for once, actually) transformed to lighten them (by hydrogenating them with the hydrogen obtained by cracking methane, or natural gas - which, by the way, is a strong emitter of CO2, since once carbon and the hydrogen and methane separated, the carbon is allowed to combine with the oxygen in the air, which forms ... CO2, which is then released into the atmosphere).

      2 - Yes, heavy fuel oil from boats pollutes more than fuel oil / diesel from cars or boilers (for heating at home). But waiting for an international carbon tax is waiting for the Saint-Glinglin. If we are not already able to put one in place at the national level, how can we believe that one day, such a tax will have a chance of being implemented at the multinational, or even global, level? In addition, it should be remembered that crude is a mixture of hydrocarbons, and that heavy fuel oil in ships is a fraction (like LPG, gasoline, kerosene or fuel / diesel). If we deprive ourselves of this fraction by refusing to use it, then we deprive ourselves of a part of the crude. Boats will therefore consume other fractions of crude (today, there is a lot of talk about making them consume fuel oil / diesel, or even gas). This will increase the pressure on current consumers of these other crude fractions. However, it is perhaps not very smart when the peak of world production of crude oil is announced by those even who denied its existence a few years ago (see for example the last annual report of the International Energy Agency, which now expects that by 2025, the global production of all liquid fuels, petroleum or not, will be 13 to 34 million barrels per day lower than to expected demand, which is currently around 100 million barrels per day and which, according to what the IEA imagines, should in these waters by 2025, see the analysis of this report in the link in my signature).

      As long as making 10000 km for a product made in a low-wage country will cost less than the same product made here, then international trade will have a bright future. If we want to "rebalance trade", there are not many solutions: either we drastically reduce wages at home (I doubt that this is socially acceptable, and unfortunately, this is what is pushing for long. term international trade), or we greatly increase the cost of transport (and that, instituted locally * and * at the borders, it can have several names, including “carbon tax”). Or, we wait until everyone is sorely lacking in oil, but then we too will be in a very serious trouble, and the effects of contraction and massive impoverishment will be much more powerful than the effects of stimulating local trade, because, like it or not, oil is the energy of transport, at home and in the world, and less oil for everyone means that * all * physical flows are under severe pressure. contraction. For the moment, it is unfortunately towards this last path that we are heading with great strides, and what is emerging then is really not a pretty sight. We would do better to agree to pay ourselves this insurance premium which is the carbon tax (that is to say, an insurance premium against future damage from our current fuel consumption) .

      3 - There are nearly 40 million cars and vans in France. If we imagined replacing 100% of this fleet with equivalent electric vehicles, we would need only 2 or 3 additional nuclear reactors, because the vehicles would be recharged mainly at night, at a time when, today, national electricity consumption is experiencing a large "Hole", and where EDF is obliged to "slow down" the production of nuclear power plants which are capable of it (roughly, half of our nuclear power plants are said to be "controllable", that is to say that we can adapt power station production on current electricity demand: you can go to ERDF's Eco2mix site to see for yourself how French nuclear power plants are managed day after day). Night charging of electric vehicles would then make all nuclear reactors operate as in broad daylight, and calculations show that there would not be much electricity needed to be able to charge all electric vehicles (in this case, roughly speaking, the equivalent of 2 or 3 additional reactors).

      4 - The batteries manufactured by Bolloré are (fortunately or unfortunately, I don't know) peanuts. Lithium-ion battery market and lifecycle studies show that China manufactures most of our lithium-ion batteries today. Which is not without posing geopolitical problems, by the way (China may decide one day to turn off the battery tap, and that will put us in a hell of a mess).
      As for the recycling of batteries, technically, it is quite possible. But since recycling a battery costs more energy (and therefore less) than going to extract, on the other side of the world, raw materials in mines and salars to manufacture a new battery, we do not recycle batteries. used. And there is a strong risk of not recycling them anytime soon (in any case, in a massive way).
      I would add by the way that I was a fervent supporter of electric vehicles but that I came back: in my opinion (but this is only my opinion), we will never have nearly 40 million vehicles electric vehicles to replace the nearly 40 million thermal vehicles. Because for at least half of our population, these vehicles will always be far too expensive and unaffordable. The public authorities would do much better to regulate the fuel consumption of thermal vehicles for sale, so that their consumption is divided by 3 by 2030 (technically, cars at 2 L / 100 km, it is already possible; on the other hand, we will have to agree to abandon 4 × 4 and other “SUV” so greedy, and adopt vehicles much narrower, much less tall and much less heavy ... and ban advertising for fast and powerful cars!) . And to avoid any rebound effect, at the same time, it will be necessary to increase the price of fuel by the same amount, so that for the end consumer, the cost per kilometer traveled remains the same.

      5 - Revising your story is very useful: it clearly shows that cutting off heads leads nowhere, apart from leaving the field open to anarchy, then to more tyranny. It took nearly 90 years for France to become lastingly democratic after cutting off the head of its king. And in a tyranny, it becomes impossible to publicly demonstrate, even once, one's discontent: arbitrary arrests and assassinations of political opponents once again become the norm. Is this really what we want for our country?

  2. This is an interesting page. I would point out, however, that one should not confuse pollution from refineries or power plants, which being localized can be corrected, with pollution from vehicles, which is spreading, cannot be decontaminated. Petrol vehicles generate little more CO2 than fuel oil (25%), but other pollutants are much less toxic and less numerous with petrol.
    Another remark, we confuse the pollution which poisons us with the minor pollution which, slightly polluting the atmosphere, supposedly produces global warming. The earth has experienced many warming and cooling which we are not interested in the cause. We therefore absolutely cannot say that we are at the origin of the warming since we cannot say if it is not natural.

    1. Just reverse the major and minor. A few more fine particles (and indeed less in months) have an immediate negative effect, but will not kill humanity. The invisible pollution, without immediate but global effects, that constitutes the emission of GHGs which causes progressive and lasting warming, is without comparison and will be just THE problem of humanity for the century to come. So to speak of “minor” just because we are unable to conceive of anything other than the immediately perceptible…!

  3. Interesting page, except on the point of water, where this article is completely wrong. Even though water vapor is the number one greenhouse gas in importance and effect on our climate system, the atmosphere is already saturated with water, causing any excess water vapor to condense into liquid water. in a few hours (in our latitudes) to a few days (in the driest regions of the Earth), and is fully recycled in at most a week, in the form of rain. The effect of excess water in the atmosphere on climate (in terms of "radiative forcing" to be precise) is therefore virtually non-existent. Nothing to do with CO2 which will remain in the atmosphere 5000 or 10000 years before being naturally purified.

    1. Thank you for the comment.

      a) I have always learned that the lifespan of atmospheric CO2 was 120 years ... so far from the 5 to 10 000 years that you mention

      b) The article concerns more the creation of “fossil” water therefore “ex nihilo” and its inclusion in the natural water cycle than its presence in the atmosphere (average lifespan of water before condensation: 2 weeks). We cannot speak of recycling since it is water that did not exist BEFORE.

      Billions of liters of water are created by combustion of fossils every day: just oil at 90 million barrels per day is more than 10 billion L of water created from "nothing" per day ... or more than 400 million L created every hour or more than 100 m3 / s just for oil!
      Ok this is low compared to atmospheric water and the evaporation capacity of the oceans but in the end it is not at all that it is so negligible!

      It rains how much on Earth permanently and on average in m3 / s? History to compare?

      1. Regarding the volume of water created of fossil origin, it does not change the amount of atmospheric water since the atmosphere is already saturated as specified in the initial comment. The few million m3 of water added in the water cycle are therefore in liquid form and have no impact on the greenhouse effect, they simply add to the volume of existing terrestrial water, either more or less 1,4 billion km3 ... If we take a totally pifometric value of 100 million m3 produced daily, that makes 36,5 billion m3 / year, i.e. more or less a factor of 10 to the power of 9 of the existing (1 km3 = 1 billion m3). Reduced to an ocean surface area of ​​approximately 380 km000, the annual rise in the oceans attributable to this production and independently of any other phenomenon would therefore be approximately… 000 nanometers! We can therefore say that the impact of this water creation is very negligible ...

      2. Thank you Rémi for these verification calculations. In liquid volume yes ... it is negligible and I never had any doubt about it, on the other hand in “gaseous” volume and in terms of “local” climate there may be an influence of the water vapor “created by the man ". It snowed recently near the Cattenom power station… and not elsewhere (well not at that time). This “nuclear” vapor creates a micro climate. It is quite possible that this is the same with water vapor from fossil fuels in large cities… no?

      3. We can discuss the impact of water re-vaporized by man on the climate, even if apart from a very temporary and local effect I doubt that this could change things in the long term ... Once again , the atmosphere being almost saturated with water, any excess ends up falling (quickly…) to the surface and ultimately into the sea. This can therefore probably influence the (very) local weather, but not the (planetary) climate .

        But above all, and to come back to the initial subject, this emission of vapor created by man is not correlated with the quantity of “neoformed” water. As your example on snow shows, it is much more due to the cooling systems of power stations in particular, or of large industries, than to residues from combustion products.

    2. I don't agree with neglecting the water vapor factor. Indeed the atmosphere is not saturated with water, if this were the case the humidity rate would be 100% at any point on the planet. Measurements show that there has been an increase in ground level water vapor from 10g of vapor per kg of air in the 40s to 10.75g today. or nearly 0.1% per year. This is not the magnitude of the increase in the CO2 rate, but as the induced greenhouse effect is 2.5 times greater the result can be compared.
      Below is a link to a linkedin post.
      https://www.linkedin.com/pulse/gaz-%C3%A0-effet-de-serre-jean-armand-navecth/
      Would I have brought wind to the mill?

  4. Hello simple question how can a vehicle produce more than it consumes?

    Let me explain my car consumes 6l / 100km for 130g./km so in my calculation base, 1300g.CO2 / 10km, 13000g.CO2 / 100km, 130000g.CO2 / 1000km.

    130kg / 1000km for 60l consumed knowing that the liter of gas oil = +/- 0.850kg so for 60l = +/- 51kg.

    So how do I consume 51kg of diesel I produce 130kg of CO2?

    1. Hello,

      The calculation is correct: 51 kg of diesel will produce 130 kg of CO2. And 130 g / km is consistent with a car that consumes 6L / 100km.

      The answer is in the equations in the article: the extra mass comes from the oxygen in the air. The combustion of fuel takes oxygen to transform it into CO2… and H2O…

      It is only the Carbon and Hydrogen atoms that come from the fuel.

      The molar masses are as follows:
      C = 12
      O = 18
      H = 1

      So on CO2 of total molar mass 12 + 2 * 18 = 48 g / mol, the mass of O2 is 2 * 18 = 36 g or 36/48 = 75%.

      So 75% of the mass of CO2 released by combustion comes not from the fuel but from the atmosphere (this does not change the problem of warming at all) ...

      Here I hope it is clearer.

      Have a good day

  5. There remains an argument in favor of LPG, apart from the emission of CO2, it is the only fuel produced exclusively from petroleum. I mean that its manufacture does not affect agricultural production and the increase in the price of food raw materials globally unlike others which contain an increasingly high percentage of alcohol or vegetable oil.

  6. Bonjour à tous

    The subject was raised with the commentary on the cracking, but as always we talk about the rejection of CO2 exhaust outlet, but when is it that of then at the pump which represents at least 3/4 of the releases.

    There are other factors:
    - The extraction of crude
    - Transportation of crude / product (crude is not extracted locally)
    - Cracking (see the previous comment)
    - Refining and treatments (de-sulfurization, etc ...)
    - The distribution

    What I know (source Elf, it dates) the treatment of diesel is very expensive, Elf said it takes just for the de-sulfuring the equivalent of a ton of heavy fuel oil for 1 ton of diesel, also knowing that in this process also uses hydrogen (which is itself very expensive to produce in CO2 equivalent release)

    From what I had read, but unfortunately it is not precise enough or detailed enough, and I would like to have more info on it, than just the values ​​below:
    This would be the equivalent in rejection for:
    - Diesel: 5 liters for 1 liter consumed
    - Gasoline: 4 liters for 1 liter consumed
    - Ethanol: 2,5 liters for 1 liter consumed (deduct what is returned by the plant)
    - Others … ?

    But how are these values ​​calculated, does this take into account the additional components used such as the production of hydrogen?

      1. According to the Ademe Carbon Base, we are at 15.9kgCO2e / GJ PCI for “upstream” emissions, and 75.7kgCO2e / GJ PCI for combustion.
        That makes roughly 20% of emissions to add more to the combustion to take into account the “upstream” emissions.

  7. Classes available every day from Nine AM to Twelve midday.
    With regard to speed on motorways, many people defend the idea of ​​lowering it to 110km / h instead of 130 in order to reduce emissions by 15 to 20%…!
    Thus, suppose that a vehicle consumes 8 liters of petrol or 7 liters of diesel at 130 km / h, we can think that by reducing its speed by 15% and therefore driving at 110, it lowers its consumption (and emissions CO2) in the same proportions, 6,8 l in petrol and 5,9 in diesel. This is indeed a good result, but I do not hear about the duration of pollution!
    Indeed, if the vehicle takes 1h to make 130kms, it will take 1h and 11minutes while traveling at 110km / h or 18% of additional time. It is therefore necessary to add 18% to the consumption obtained and the 6,8 l of petrol becomes 8 l and the 5,9 l of diesel drop back to 7litres.
    In conclusion, to reduce emissions by 15% from 130 to 110km / h, as it is sold to us, we would need a differential of 1/3 of lower consumption between these two speeds. The efficiency of current engines and the multiplication of gear ratios, including automatic, translate into a much smaller difference, most often less than 10% and would therefore have the effect of reducing speed, increasing emissions ...!
    Amazing no. !!!

    1. This reasoning could have been correct but it is not: because you start with consumption of 8 or 7 L… per hundred and not per hour! There is no need to correct the distance traveled….

      Nevertheless I am all the same skeptical about this reduction: the 80 km / h of the secondary roads did not serve any CO2 level !! No more than security ...

      I therefore doubt very much that the 110 motorways serve the interests of the climate any more!

      Agree with you on the technological aspects (gearbox, engine performance…) which means that a car will consume more at 30 km / h than at 90 km / h !!

      ps: you can come and participate in our forum to exchange ideas https://www.econologie.com/forums/ we had a similar debate on the 80 km / h https://www.econologie.com/forums/nouveaux-transports/analyses-economiques-sur-le-passage-de-90-km-h-a-80-km-h-en-france-t15672.html

      1. Classes available every day from Nine AM to Twelve midday.
        lowering the speed is not the solution (vehicle speed), I do not agree indeed, it is the tachometer that must be looked at; with my diesel vehicle, when I drive at 70 km / h my tachometer indicates 1500 laps and when I am at 90 km / h my tachometer is at 1350 laps. The reason is simple, we cannot drive at 70 km / h in 6th or 8th in automatic; we must downshift manually or in automatic (this is done by itself).

    2. The reasoning seems wrong to me because only the amount of Co2 per km traveled counts. It doesn't matter the weather. Except in the case of a truck driver who will do even more km in his day if he drives faster. But perhaps there will then be a need for fewer drivers, and therefore, there too the weather does not change anything.

    3. Hello,
      I am correcting a reasoning error:
      at high speed the consumption (in liters per 100 km) is proportional to the work done to counter the air resistance (the rolling resistance is low in comparison), this air resistance varies not proportionally with the speed but with the square of the speed: in other words, by going from 110 to 130, you increase consumption by 130/110 * 130/110, ie by about 40%. This justifies reducing your speed on the motorway to save money!
      Another way to calculate: the power absorbed to counter the resistance of the air (equivalent to liters per hour) varies as the cube of the speed, while the distance traveled in an hour varies in proportion to the speed: by dividing the one by the other we fall back on a variation of consumption in liters per hundred which varies as the square of the speed.

  8. Hello,
    I am a boon in the areas covered by this excellent site.
    We are talking about CO2 pollution from diesels and as in the garage where I left my diesel car from 1993 I wonder if it would not be possible to attach an extractor to the exhaust of the exhaust and compress the gases in a tank… and ride with it all.
    It is surely totally utopian and impractical.
    Thank you for your lighting

  9. Hello ladies and gentlemen,
    For some time now we have been watching an SUV hunt and I find myself quite embarrassed to be pointed out, in fact I drive in a Kadjar Renault 1.5 DCI from 2016 (twin brother of the Kashquai Nissan, the creator of the genre).
    My vehicle weighs as much as my wife's Scenic, i.e. 1.4 T with the same engine but from 2014.
    My vehicle consumes 4.5 l / 100 on the highway at 110 km / h when Madame's Scenic consumes 1 l more (due to the antipollution system which injects fuel before the DPF on this version, so 1 fifth injector).
    My son benefits from a company vehicle which is 1 year old, powered by gasoline (a very high-end Golf, therefore rather small and over-equipped) which struggles to consume less than 10l / 100 in current use but becomes more virtuous on the motorway without for as much to fall below 7 l to 100.
    I therefore believe that my SUV is far more virtuous than the other vehicles around me and yet it is he that we look askance ...
    In addition, as far as I am concerned, it is ankylosing spondylartritis which forces me to acquire a top-of-the-range vehicle, not possible to fit into low-lying cars without suffering.
    Where are the logic?
    Your writings are very interesting.
    Bonne journée.
    Joel.

  10. You have to believe that psychotherapy is a very widespread national sport: I do not see on this excellent information site the slightest information about a German specialty: non-fossil synthetic fuels. However, it has been a dozen years since these innovative projects were in the media, on the other side of a large border river, and still a little bit on this side.
    Thus, the carbon taken from the atmosphere can be grafted onto hydrogen, and therefore used in a closed cycle, without adding a fossil source which causes climate change. It therefore becomes possible to envisage perpetuating thermal engines where they remain essential (plug-in hybrids, motorcycles, and of course trucks, boats, planes, etc.) without having to completely overturn industries weakened by excessively environmental standards. drastic.
    The production potential is immense starting from solar energy, which makes it possible to produce the necessary hydrogen at a lower cost, as demonstrated by a small Finnish technical university (LUT: Lappeenranta) which has published since 2016, numerous scientific publications (under the names of C. Breyer, M. Fasihi,…), scenarios,… embodying a new, apparently counter-intuitive concept of “Neo Carbon Economy”.
    Recently, the start of media coverage has appeared with the Porsche-Siemens project in Chile, using wind energy to obtain MTG gasoline, which will be used next year in F1, at the 24 H of Le Mans, before d 'to be marketed. Another project in Norway will also shortly be producing kerosene.
    To discover the parallel universe of these non-fossil synthetic fuels, take the time to browse the NCSH website (15 min): ncsh.eu.

    1. Hello,

      Thank you for this very interesting comment, I invite you to discuss in more detail and present your work on the forum alternative fuels: https://www.econologie.com/forums/biocarburants/

      Otherwise we were talking on these pages (among others) of some synthetic fuel:

      Synthesis of alternative fuels: https://www.econologie.com/carburants-substitution/
      Laigret process: https://www.econologie.com/biomasse-petrole-synthese-travaux-laigret/
      Fischer-Tropsch process: https://www.econologie.com/fischer-tropsch-combustible-solide-carburant-liquide/

      (these links have just been added at the end of the article)

      See you soon

  11. Everything is fine, but only from inaccurate calculations, because if you take the ever-increasing costs of transporting and extracting raw materials to power the power plants that supply electricity and battery production, and the same cost of extracting raw materials and transporting the materials needed to produce them, it could turn out differently than what you preach. It's a secret that the least processed product is the cheapest

  12. I don't understand anything about co2 emissions.
    1) 6/100 PB95 = 6*2,3 = 13,8
    2) 7,5/100 LPG = 7,5*1,7 = 12,75
    3) 5/100 GB = 5*2.6 = 13

    It seems to me that CO2 emissions are very similar for different fuels.
    Actual fuel consumption values ​​for citroen c3 1.2 vti 82KM, diesel 1.4hdi

    1. Good evening, have you taken into account in your calculations that one kilo of methane is equivalent to approximately 1,7 liters of gasoline?

  13. Thanks for the insightful article on CO2 release or emission per liter of fuel. I always thought diesel was more harmful, but I was surprised to read that petrol emitted more CO2 per liter than diesel or LPG. I also found it interesting to know how much CO2 a car emits per year. It made me realize my contribution to global warming. I am a driver and I am concerned about the environment. In the future, I would like to drive less and use public transport or the bicycle more.

  14. Attention, the use of a fuel generates other emissions than those of combustion! Liquid fuels, resulting from refining, have an additional cost in greenhouse gases. Transport and storage also have a GHG cost. We must therefore consider the emissions "well-to-wheel" (well-to-wheel) ... we find this information on the internet.

  15. Hello,
    I have to buy a new car and the parameters on which I base my purchasing decision are, on the one hand, how much the car pollutes and, on the other hand, how much it would cost me in fuel per 100 km traveled. I'm hesitating between 2 cars: the Dacia Stepway LPG (for which Dacia declares a consumption of 7,1 liters per 100km traveled and 114g/km of CO2) and a hybrid car, the Toyota Yaris Cross (4,5 liters per 100km and 102g/km of co2). Could you help me with this calculation? Thank you a lot!

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