Reviving a moribund product, Storstockholms Lokaltrafik (SL), the public transport operator in greater Stockholm, has purchased another 123 ethanol buses for its fleet from Scania.

Scania, which had been the world’s largest maker of buses running on E95 (95% ethanol, 5% ignition-enhancing additive) had ceased production of its ethanol-adapted engine in 2003.

Stockholm already has the world’s largest fleet of ethanol buses, which operate mainly in the inner city. The new buses will be put into suburban operation during autumn 2005. When deliveries are concluded in early 2006, around 350 ethanol buses will be operating in the SL fleet.

Since 1990, Scania has supplied around 450 ethanol buses to Swedish cities, of which more than 200 are rolling in the inner city of Stockholm.

The ethanol buses use Scania’s 230 hp, 9-liter diesel engine adapted for ethanol. Exhaust emissions meet Euro 4 standards.

Scania also offers a natural gas-fueled version of its 9-liter engine that develops 260 hp, while meeting projected Euro 5 emissions targets.

Ethanol buses were the subject of a variety of studies in the 1990s, including trials by Los Angeles and tests by NREL. The high operating costs of using ethanol buses dampened enthusiasm at the time.