Ethanol efficiency debated in U.S, while Scania's ethanol powered engine cuts CO2 90% vs gasoline.

While in the U.S. ethanol's efficiency (in low compression engines) is debated, in Sweden, a company making ethanol powered buses (for 18 years) has a new ethanol fueled diesel engine that will cut CO2 emissions vs gasoline 90%.

HOW? Ethanol is a high octane fuel which can be used in high compression applications producing much more power from a given displacement. The result is you can downsize the engine and reduce fuel consumption - and GHG emissions!


New highly efficient diesel-ethanol engine- ready to cut fossil CO2 emissions by 90% (Oct 2007).

Scania has produced ethanol buses for more than 18 years. The technology is mature and viable for intense everyday city service, as verified by fleet operators in several Swedish cities. Time has come for Scania's third ethanol engine generation, which achieves the same efficiency as a conventional diesel engine, while meeting Euro 5 and EEV emission levels.

Scania regards ethanol as the most viable renewable fuel currently available for urban operation, since it can contribute without delay to a sustainable public transport system.

By sustainable public transport Scania means sustainable in an environmental and economical perspective, using fuels that are compatible with current engine technology.

Ethanol is by far the most cost-efficient renewable fuel option on the market today, taking into account factors like availability, infrastructure and access to proven technology. New technologies such as hybrids are around the corner and fuel cells could become viable in ten years’ time, but there is no reason to wait.

The transition to renewable fuels can start NOW using existing technology.
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Actually, you don't have to go to diesel engines to get the fuel efficiency benefits of ethanol. JUst use turbo-charging (or super-charging) and down-size the engine.

Three MIT scientists have designed an engine which uses Direct injection of ethanol with turbo-=charging to get 30% BETTER mpg than the typical low compression internal combustion engine runnning on gas(http://www.psfc.mit.edu/library1/catalog/reports/2000/06ja/06ja016/06ja016_full.pdf">MIT paper). The engine costs about $1,000 - $1,500 more to build and uses 5% ethanol and 95% gasoline. Ethanol is a high octane fuel (115 vs high test gas 92-93) so you can use turbo-charging to get more power out of a given displacement and downsize the engine thus using less fuel!


Ford is now a co-owner of this engine design and is currently selling it only in the Lincoln MKS. (the engine can operate on gasoline but to get the full benefit of direct injection plus turbo-charging you need to boost it with 5% ethanol - directly injected into the combustion chamber). Ford plans to offer this engine across it's entire line of vehicles in the next few years. (But this is much more likely to happen if we see many more ethanol pumps in gas stations. Ford isn't likely to commit to building lot's of these engines unless people can see a clear benefit to using them .. i.e. wth ethanol boosting).

to run cars on ethanol, when we can't even seem to feed all the people on this planet.

could probably be used for growing food?

More efficient.

if every car and truck in the fleet used this engine the ethanol needed to supply these engines would be 5% of the total fuel supply. We produced more ethanol than that percentage in 2009.

You may not be aware of this but many people are working on developing making ethanol from cellulosic sources, - i.e. inedible plant sources.

Ethanol is not going to do it alone. We will need electric cars to also reduce GHG emissions from cars, but this will take time. It will be probably take 20 years before we see appreciable reductions to GHG emissions (say 20% to 30%) from cars by replacing ICE powered cars with hybrids and pure electrics. We need to get reductions sooner than 20 years out. With an engine that costs about one third to one forth of a hybrid and even a smaller proportion of the cost of plug-ins adoption will occur much more rapidly. Meaning we can get reductions sooner.

Sooner is important as Global Warming is accelerating. Any reductions we can achieve sooner will be extremely important in terms of slowing and hopefully getting Global Warming under control later.


.. of course, I personally doubt that people will realize how important timing is (until it's too late). I do not think we will do the things need to do to reduce GHG emissions sooner rather than later. THe result will be we won't get Global Warming under control later. So millions of people will be running short not only of food but also water in a few decades. That's my guess anyway.

Probably in horsepower.

But that's just a guess.

Hydrocarbons fully burned produce a static amount of CO2.

A Hummer or Prius for example both produce exactly 19.2 pound of CO2 per gallon of gasoline burned.
Prius has lower carbon footprint because it goes further (more effective work) on the same gallon (9 mpg vs 50 mpg).

A 30% improvement in fuel efficiency should result in 30% less CO2. If you oxidize hydrocarbons (combustion) you will produce CO2. It is unavoidable.

one gallon in twenty. So the 23% less fuel consumed for each of the 20 gallons, on a per gallon of ethanol basis (1 out of 20 gallons) is twenty times greater. so the reduction in gasoline consumed (and GHG emissions)is 20 times the 23% or 462% reduction vs gasoline. Somewhat greater than 90% reduction.


THat's what using 1 gallon of ethanol of every 20 gallons of fuel consumed does for you.

So we are already getting CO2 reduction from partial ethanol use (however dubious that may be).

to get the kind of fuel consumption reductions (or GHG reductions) per gallon of ethanol i am talking about.

The measure is meaningless unless its (mass of C02 emitted)/distance moved. That can be expressed as mass/mile to move a standard measure of mass, such as a ton. The (mass moved) and (distance moved) should both be constants.

A typical expression would be: 1134.3 ton-miles being shipped by truck (0.3725 lbs CO2 per ton-mile) gives you a total emissions of 422.52 lbs CO2.

The first mention of a technology is referencing an all ethanol engine (E100).

The other is about a different engine design that augments gasoline with ethanol.

Ethanol is a form of energy storage with a slight net positive energy balance of fuel due to the solar input. for that reason and others it isn't a sustainable or CO2 friendly means of powering our entire vehicle fleet, but there is most definitely a role for the portability and energy density of liquid fuels in our heavy transport and dispatchable electric sectors. That alone will probably strain our production capacity so it is a good thing that battery technology and EVs are coming along.

now, notice that the engine that produces a 30% improvement in fuel efficiency (35% with stop-start ignition as used in hybrids) will reduce fuel consumption 23% (1-1/1.3) or for a 35% increase in efficiency a 26% reduction in fuel consumption (1- 1/1.35). This is without any reductions achieved by substitution of ethanol for gasoline (assuming we make more than 5% ethanol - actually we already are making a bit more than that). Notice that this (30% or 35% improvement in fuel economy using the Direct Injection engine) requires 5% ethanol and 95% gasoline *. At a price of $1,000 to $1,500 This means a much more rapid adoption of this engine. (payback in about 2 to 3 yrs with gasoline @ $4.00 per gal). As I said, getting GHG redcutinos sooner than later is important.

But, I also said in a follow-up that I don't think we will realize how important timing is until it's too late. Call me a pessimist but, I do not think we are going to get Global Warming under control. So you won't have to worry about ethanol, just many millions of people without enough water and perhaps not enough food (if GW adversely affects food production world-wide - as some anticipate).


* note that since only 5% ethanol is required to achieve the 23% (or 26%) reduction in gallons consumed you are getting 20 times that reduction (1/.05) on a per gallon of ethanol basis (1 gallon in 20 is ethanol)...or about 462% reduction of GHG emissions vs gasoline for the 30% increase in mpg (or 519% reduction in GHG emissions for a 35% increase in fuel economy). So you get a reduction of 23% in fuel consumed for all 20 gallons burned of fuel - only 1 gallon of which is ethanol. (20 x 23% = 462%).