SIEMENS

Most people wouldn’t be thrilled about having to get underneath a subway train. But Tor Hasselknippe views it as a welcome challenge. Every day Hasselknippe, a technical manager at Oslo’s Vognselskap public transport company, inspects the Siemens trains that since 2006 have gradually been replacing the more than 30-year-old subway trains previously used in the Norwegian capital. At the maintenance center, the subway cars are jacked up on rail platforms in a vast hall. Technicians work on the underbodies and put the finishing touches on the cars before sending them out into the city’s approximately 84-kilometer-long subway network. “This is one of the electric motors,” Hasselknippe says, pointing to a large rectangular block underneath one of the cars. “The complete drive unit of a train has an output of 1,680 kilowatts and is also very energy-efficient. When the driver brakes, the motor goes into generator mode and sends the electricity it produces back into the grid.”

Hasselknippe then knocks on the white outer wall of a car. “The entire shell is made of aluminum,” he says. “This makes the train extremely light.” As a result, the new subway trains consume 30 percent less energy than the old ones. “And that’s not all,” says Hasselknippe as he climbs into a passenger cabin and runs his hands over the seat covers. “These textiles are made of a very sophisticated material that not only meet all fire protection requirements but can also be recycled - which is true of 95 percent of the components in these trains. All of this makes our subway one of most sustainable systems in the world.”

Heating on Demand. It isn’t always easy to combine sustainability with the effective operation of the new subway. For one thing, around 80 percent of Oslo’s subway system is above ground, which negatively impacts its energy balance, especially in winter. “The heating system still accounts for nearly 20 percent of required energy - so we need to keep working on that,” says Hasselknippe. Engineers at Siemens Mobility in Vienna, Austria, are looking at ways to reduce the energy consumption of heating and climate control systems. “We’ve developed a heating control unit that regulates the system in line with real-time requirements,” says project manager Dr. Walter Struckl. “The unit is linked to a carbon dioxide sensor that determines how many passengers are in a car based on the principle that the CO₂ content rises with the number of people present.” According to Struckl, the unit can heat up air from the outside in line with actual heating needs. By contrast, conventional systems continually heat subway cars, regardless of whether or not passengers are on board. “Our technology should generate heat-energy savings of up to 30 percent,” says Struckl. Sustainability and energy efficiency have been top priorities in Oslo for some time. In 2002 the city, which has a population of 550,000, launched its ambitious Urban Ecology Program to cut pollutant emissions and improve its citizens’ quality of life. Among other things, the associated plan calls for a 50 percent reduction of Oslo’s 1990 greenhouse gas emission levels by 2030. This green program is already producing results. A sustainability study of 30 European cities for the European Green City Index ranked Oslo third behind Stockholm and Copenhagen. The study even gave the Norwegian capital a top ranking for CO₂ emissions, as the city produces only slightly more than two tons of the greenhouse gas per capita - mainly because Oslo covers around 60 percent of its electricity requirement with power from Norway’s large hydroelectric plants.

But there’s still work to be done, so the Urban Ecology Program, scheduled to run until 2014, also focuses on expanding the local public transport network. Studies have shown that road traffic is responsible for the lion’s share of Oslo’s CO₂ emissions. Despite high tolls for entering the city center, some 360,000 vehicles continue to drive through Oslo every day. The city government believes that improving the bus and subway system will get more commuters to leave their cars at home. Indeed, the new subway system has already demonstrated that the government may be right. “Polls show that passengers are extremely satisfied,” says Hasselknippe. “Since the introduction of the new trains, ridership has increased by around 10 percent to 73 million in 2008.” He thinks even more people will switch to the subway in the future, especially now that intervals be- tween trains have been cut in half. “Trains have been running every seven minutes 20 hours per day for a year now - and that eliminates many people’s need to drive.”