It’s time to break the lock on gridlock. If current U.S. traffic trends persist, traffic congestion will cost the nation $186 billion a year by 2030 in wasted fuel and people’s time, according to a study by INRIX Inc. released in late 2014. That cost might be low: Another source puts the potential impact in the trillions. And wasted fuel puts needless emissions into the air, undermining the environment and compromising the health of regional populations.
The INRIX study’s forecast is 50 percent higher than today’s estimated $120 billion a year in costs due to slow traffic, which is bad enough. Even worse are traffic forecasts for the major cities of Europe, Asia and the Middle East. One monster traffic jam between Beijing and Mongolia in 2010 stretched 60 miles and took three weeks to resolve.
Time for change
Clearly, such traffic trends are not sustainable, despite being driven by growth in GDP, jobs and car ownership. In the San Francisco Bay Area, with some of the most congested traffic in the U.S., INRIX figures that every vehicle in the region today wastes an average of 56 hours per year in traffic.
For a two-car household, that’s almost three weeks of lost time a year. With two $75,000 incomes in a two-earner household, that’s $8,000 a year in lost productivity. It’s a cost borne by the regional economy and the individuals’ employers, not to mention the individuals themselves in time they could spend with family, friends or in leisure pursuits.
Los Angeles. New York. Boston. Atlanta. Washington. These and most other major U.S. cities face the same problems of too many vehicles vying for too little asphalt. But road-building has reached its limits in many metro areas, given the prohibitive cost of land and construction as well as the time required to secure legal rights-of-way. And these same constraints dim the prospects for extending commuter rail in these areas, too. As one Bay Area traffic official put it, “We cannot build our way out of congestion.”
Waterways as new highways?
That’s why metro planners in regions fortunate enough to have navigable waterways, such as the Bay Area, Seattle and New York, are thinking anew about their ferry services. Electric and hybrid propulsion technologies are making it possible to improve the carrying capacity of their ferries, while reducing vessel fuel consumption and consequent emissions. Waterways are already in the public domain, so new ferries can be added with just the vessel costs and the time to build them and their support infrastructures.
Business planners are also considering ferry service as an alternative to ground transit. Major firms that have deployed buses to shuttle their employees to work are realizing those buses can get stuck in traffic same as cars, despite access to faster HOV lanes. Even with WiFi aboard the buses, employees are not as productive as they would be in an office or working from home.
Electric ferry propulsion, a fossil-fuel alternative
These planners may well take a page from the playbook of Norway’s ferry system, which launched the world’s first all-electric car ferry in 2015. Called the Ampere, the vessel carries up to 120 cars and 360 passengers across the 4.2-mile (6.8 km) Sognefjord channel that separates Norway’s villages of Lavik and Oppendal and empties into the North Atlantic’s Norwegian Sea.
The 260-foot catamaran with a hull of lightweight aluminum recharges its dual 450 kW/hour battery packs after each docking in less than 10 minutes – faster than today’s smartphones and the turnarounds of many conventionally powered ferries. As its name implies, the ferry emits zero emissions because it burns no fossil fuel. By contrast, a conventional ferry traveling the same route would consume 264,000 gallons (1 million liters) of diesel fuel a year and produce 2,680 tons of carbon dioxide and 37 tons of nitrogen oxide.
The Ampere uses a Siemens BlueDrive PlusC propulsion system with two variable-speed generator sets (gensets), each capable of an output of 450 kilowatts. These purpose-built, brushless and synchronous power plants reduce their speeds under low loads, which are typical of vessels underway. But that differs significantly from traditional constant-speed, diesel power systems with fuel-burning motors that operate at or near full speeds no matter what the load. The Ampere also operates silently, with none of the vibration that would come from a diesel power plant.
Making what’s old new again
For all its futuristic promise, electric ferry propulsion has a long history. In 1886, Siemens introduced an electric water taxi, the Elektra, to carry 25 passengers along Berlin’s Spree River. And submarines have used electric propulsion systems to operate silently undersea for more than a century. What’s new today are the ever-greater efficiencies in ship-building, using lightweight materials like aluminum and carbon-fiber, as well as in the electric propulsion systems and the battery technologies that support them.
For example, the all-aluminum catamaran hull and superstructure of the Ampere weighs about half of all-steel construction, plus its resistance to seawater corrosion eliminates the need for special paints and reduces maintenance. Electric propulsion technologies have come a long way, too, with more power able to be generated in less space, so ferries can have greater carrying capacity, whether cars, people or both. On some types of vessels, such as high-tech fishing boats, Siemens ship designers have been able to increase storage space by 40 percent.
Battery technologies are advancing quickly, as well, with greater energy densities translating into less space and weight requirements. As an example, Siemens frequently partners with specialists in energy storage systems (ESSs) for maritime applications. Lithium-ion ESS modules are available in liquid-cooled versions to boost power while reducing space and weight. Their modularity enable engineers to easily design and build as much capacity as a vessel needs in the smallest possible space, with the least amount of weight.
All-electric or electric diesel hybrid systems?
The 4.2-mile (6.8 km) distance of the Sognefjord channel that the Ampere plies is considered ideal for all-electric propulsion, which is practical up to 12 nautical miles. After that, due to charging limitations, an electric-diesel hybrid approach is best. An example is the hybrid-powered Prinsesse Benedikte, a ferry connecting Denmark and Germany over the 12-mile (19 km) Puttgarden-Rødby water passage. The 460-foot (140-meter) vessel can carry more than 360 cars and 1,140 passengers per trip. Its propulsion system operates in all-electric mode when disembarking or docking, then switches to diesel once underway.
The system comprises generators powered by 17,440-kilowatt diesel engines. They produce electricity to drive its electric motors with the help of frequency converters. Siemens integrated a lithium-ion energy storage system (ESS) with a capacity of 2,900 kilowatt-hours into the drive system. The ESS compensates for the motors’ varying energy requirements depending on whether the ferry is moving or docked. As a result, the diesel engines can operate more evenly and near their optimal efficiency. The addition of a battery has enabled the ferry to save up to 15 percent on fuel, while helping to reduce wear on the diesel engines.
Ferries, the green mass-transit alternative
While surface vehicles powered by fossil-fueled, internal combustion engines are not going away soon, all-electric and electric-diesel hybrid ferries have bright futures as viable, green alternatives to congested highways. That’s why forward-thinking traffic planners in both the public and private sectors of metro regions with navigable water are giving both approaches careful evaluations. And that’s not to mention their much less cost and time to deployment compared to building new roads and rail extensions. For all these reasons, ferries are destined to play an ever-greater role in those metros’ mass-transit mix, helping break the lock on their gridlock.
Kerry Darnell has over 20 years’ experience in automation and drives systems, with multiple global companies. For the last 11 years, Darnell’s focus has been exclusive to the marine industry, particularly drives and diesel electric and hybrid propulsion systems, power distribution and vessel automation and control, and for the last four years he has been in business development at Siemens Drilling and Marine. Darnell’s main emphasis is on the introduction of hybrid electric and all electric propulsion systems into the mass transit market with a concentration on ferries, water taxis, excursion boats, and offshore vessels.
