Scania Delivering 85 New Ethanol Buses for Stockholm Fleet
21 June 2010
Scania is delivering 85 ethanol-powered buses to Nobina, which operates on behalf of the Stockholm regional public transport company, Storstockholms Lokaltrafik (SL). Scania’s ethanol bus features a modified diesel engine running on a mixture of 95% ethanol with 5% ignition improver. (Earlier post.)
The order includes buses for city, suburban and regional traffic to be stationed at SL’s depots in Bromma, Tyresö and Södertälje outside central Stockholm. Deliveries will begin in August. The buses will be equipped with Scania’s third generation five-cylinder 270 hp ethanol diesel engines, which meet Euro 5 and EEV emission standards.
Scania has more than 20 years of experience with ethanol buses. The company has delivered a total of about 700 ethanol buses, more than 600 of them to Swedish cities. In recent years, Scania has also delivered ethanol buses for commercial service in Great Britain, Spain, Italy, Belgium, Norway and elsewhere.
Stockholm, the capital of Sweden, has the world’s largest fleet of ethanol buses, and as recently as during the past year, Scania delivered 85 ethanol-powered articulated buses for operation in SL’s service area.
SL’s owner, the Stockholm County Council, has set a target that at least 50% of all passenger transport in its territory should occur using renewable fuels by 2012. At the end of 2009, the figure was nearly 30%.
Compared to a conventional diesel engine, ethanol-powered vehicles can reduce fossil carbon dioxide emissions by up to 90%, Scania says.
great ! good news for swedish
congratulations you are one step nearer to be oil free
50% of the buses totally oil free
Posted by: luis | 21 June 2010 at 11:39 AM
If this is cellulose ethanol, yes. You can run diesel on methanol, but it takes another set of injectors to go along with the diesel. Apparently diesel and methanol don't mix.
Posted by: SJC | 21 June 2010 at 03:44 PM
SJC: Could cellulosic Butanol be more compatible?
Posted by: HarveyD | 23 June 2010 at 08:51 AM
I don't know, I am not a diesel expert. Butanol works for spark engines and might even be used as the 15% of M85. They need something to start a cold engine and that could be it.
Posted by: SJC | 23 June 2010 at 10:27 AM
Reading previous articles, they increased the compression ratio on the engines for compression ignition with ethanol.
"To use the E95 blend in the diesel engine, Scania raised the compression ratio from 18:1 to 28:1, added larger fuel injection nozzles, and altered the injection timing.
Different gaskets and filters are required, as well as larger fuel tanks—the engines burn 65% to 70% more ethanol than diesel."
"thermal efficiency of up to 43%, compared to thermal efficiency of up to 44% for diesel, according to Scania."
Those numbers don't quite coincide, but that is what they say.
Posted by: SJC | 23 June 2010 at 01:20 PM
@SJC,
I'm no expert either, but have been reading for a while.
Both Sweden and Brazil have bets on biofuels and ethanol. Both have shown it can displace gasoline in Otto cycle engines with minimal drawbacks. Brazil uses hydrous ethanol (~95pure ethanol mixed with water, cheaper) while Sweden chosen E85 (cold weather proof).
Diesel engines is whole other game. There is a huge desire in displacing it with many different approaches.
This one from Scania uses 95% ethanol mixed with a "special additive", an explosive if fact, to obtain the desired "compression ignition".
This setup promise far lower (soot, SOx) emitions than diesel, while using proven sugar cane's "best solar energy harvesting" profile to produce the biofuel economically. (Far more efficient than soy or palm derived biodiesel).
They're demonstrating and testing in Sao Paulo, Brazil as I learned. It has not been widely deployed so far. It's in a kind of proof of concept phase.
(There in an interesting video on this in the proceedings of the Ethanol Summit 2009 sponsored by Unica in SP including some of the approaches.
Audio is unfortunately only in portuguese.
http://ethanolsummit.wordpress.com/2009/06/03/etanol-nova-opcao-para-motores-diesel/
Slides in english:
http://www.ethanolsummit.com.br/upload/palestrante/200906260113396251689676782.pdf).
Ethanol is not toxic, which is a HUGE benefit compared to Methanol.
Ethanol has 70% of the heating (chemical) energy of similar volume of "pure gasoline". Methanol has 50%. Gasoline has ~80% of the heating energy of similar volume of Diesel. So ethanol has ~55% of the energy content of same volume of diesel, requiring ~82% more fuel volume to deliver same amount of energy.
(keep in mind it's an approximation. energy content depends on the mass. volume is temperature dependent.)
(BTW, there is a good presentation: "Fuels of the Future for Cars and Trucks"
http://www.eere.energy.gov/vehiclesandfuels/pdfs/deer_2002/session1/2002_deer_eberhardt.pdf
with charts comparing fuel/energy sources).
All ICEs are thermal engines, and it's theoretical efficiency is derived from the compression ratio that is higher on diesels. Using ethanol as Scania, or methanol derived DME as Volvo, would still recover something similar as a percentage from the chemical energy in the fuel. Fuel flow needed would need to be adjusted to compensate for the lower energy-by-volume density of the specific fuels.
There are unknowns in the cost of the additive, and engine extra maintenance needed.
Posted by: CelsoS | 24 June 2010 at 02:11 AM