Greening the World’s Blue Highways

Ferries today are typically fueled by oil, but when they first got their start beasts of burden propelled them across the water. In the Roman Empire, two oxen walking in front of a ship with a water wheel supposedly powered one of the first known ferries. 

Thousands of years later, animal-powered boats, called “team boats,” were widely used as ferries in 19^th century America. But as the Industrial Revolution took hold, coal-burning steamboats replaced the horse-and-mule ferries used in places like Lake Champlain and the Mississippi River. Across sectors and societies, the shift to fossil fuels turned the environment wetter, warmer and more polluted.

Greenhouse Gases

As cracking ice sheets, intensifying hurricanes and noxious air make the effects of replacing animal and human power with oil and gas painfully apparent, certain governments are encouraging more environmentally friendly modes of transportation to combat climate change.

The shipping industry is a prime target for reducing greenhouse gases, especially as its emissions have risen in step with its recovery from the 2008-2009 global financial crisis. A report by the International Council on Clean Transportation noted that, between 2013 and 2015, shipping’s CO₂ emissions grew from 910 to 932 million tons. Moreover, although fuel efficiency improved on average, ships burned more fuel as they traveled farther, faster and more frequently.

To reduce emissions, the IMO has adopted two key policies. First, the Energy Efficiency Design Index (EEDI) will require all vessels built after 2025 to be 30 percent more energy efficient than those built in 2014. Second, targeting the world’s existing fleet, the Ship Energy Efficiency Management Plan (SEEMP) promotes cost-effective modifications that improve fuel use.

Although these measures have been criticized as not going far enough – especially since the more stringent regulations for newbuilds only affect about 15 percent of the global fleet – they represent a start.

While container ships, bulk carriers and oil tankers emit the bulk of the world fleet’s greenhouse gases, the public and private sectors are increasingly trying to shrink ferries’ carbon footprint as demand for “blue highways” ramps up. Last year, newly opened services included an expanded ferry network along New York City’s rivers and a long-distance service between Spain and Ireland.

Annually, the ferry industry transports 2.1 billion people, close to the 2.3 billion passengers that travel by air. While the average ferry emits 0.12 kg of CO₂ per passenger-kilometer – significantly less than airplanes and about half that of the average automobile in the U.S. – it’s still higher than other forms of mass transit like trains. Fast ferries, which service places like the Greek Islands and the densely connected Baltic Sea, are even more polluting as they race across the seas.

Cutting-Edge Technologies – the European Example

As animal-propelled ferries aren’t about to make a comeback, companies are instead exploring cutting-edge technologies like hybrid energy and electric batteries. Because ferries tend to make shorter journeys than trains or planes, they are a perfect fit for current battery capacities.

Most innovations for ferries are being engineered and implemented in Europe, which has numerous ferry-dependent communities and environmentally progressive governments. In 2015, the Norwegian government began requiring all new ferry tenders to have low or zero-emissions technology installed. Meanwhile, the E.U. is funding a variety of green ferry projects including Denmark’s “e-Ferry,” a 100-percent electric ferry that runs on the world’s largest battery and emits zero greenhouse gases.

Swiss-based energy storage solutions provider Leclanché is a key participant in the e-Ferry project. The Leclanché Marine Rack System (MRS), a modular, lithium-ion battery system that can deliver 4.2 Mwh of energy, will power the e-Ferry, allowing it to sail up to 21.4 nautical miles before recharging. The goal is to have 10 e-Ferries in operation by 2020 and 100 by 2030, potentially representing a total reduction of 100,000-300,000 tons of CO₂ emissions.

Building on its success with e-Ferry, Dean Jennings, the company’s Vice President of e-Marine, says, “Leclanché has been awarded four ferry contracts on top of the e-Ferry in the last three months, so the sector is definitely taking note of the technology and the potential savings operators can achieve.”

Apart from the E.U.-led e-Ferry project, other efforts are underway in Denmark to develop environmentally friendly ferries. The peninsular country is located at the center of the dense network of ferries on the Baltic Sea. From the capital, vessels depart for places as close as just across the Kattegat in Sweden to as far away as the Faroe Islands.

In 2013, Copenhagen-based Scandlines became the world’s first shipping company to make large-scale use of a hybrid system that stores energy in batteries onboard the ship. Anette Ustrup Svendsen, Head of Corporate Communications, explains, “When the engine needs more energy than the diesel generator can supply, it uses the batteries’ energy – and when there is less need for energy, excess energy is saved in the batteries. The hybrid system optimizes the engine’s performance, ensuring maximum fuel efficiency.”

Thanks to this innovation, the ferry’s carbon dioxide emissions are reduced up to 15 percent. Scandlines plans to reduce energy consumption as much as possible with its Zero Emission Project, which is moving the company’s ferries “step by step to 100 percent battery operation,” Svendsen adds.

Another Scandinavian company that has achieved significant breakthroughs in making ferries more environmentally friendly is ABB. Andre Luiz da Silva, Vice President of Global Sales for the company’s New Markets Segment (Marine & Ports), says, “ABB is more than ready to deliver systems for ferries that operate within low-emission or emission-free routes.”

Last November, the company converted two ships that service the 4.3 nautical mile route between Helsingør, Denmark and Helsingborg, Sweden from conventional diesel engine operation to battery power, making them the world’s largest emission-free ferries. The engineering involved installing a 4160 kWh battery on each vessel, both nearly 30 years old and over 100 meters in length, as well as battery racks, energy storage control systems and ABB’s groundbreaking Onboard DC Grid™ power distribution technology.

As the company moves towards achieving its vision of “electric, digital and connected” shipping, it’s testing even more futuristic technologies like autonomous ferries in Finland and silent, battery-powered ferries in a Norwegian UNESCO World Heritage-listed fjord.

Asian Haze

If the future of ferries in Europe is greener, a thick haze of smog and fumes still chokes passenger vessels in Asia. Government concerns about ferries there center on improving safety in archipelagic countries like Indonesia and the Philippines rather than on minimizing carbon footprints.

ABB’s Silva explains, “I believe Asia has a huge potential. However, in most of the countries there’s still a lack of clarity in regard to environmental policies for zero-emission shipping. This can create uncertainties among shipowners on the way forward toward adopting new, greener technologies.”

Despite the uncertainties, there are still a handful of envelop-pushers across the continent that emits more greenhouse gases than any other due to its enormous population and fast-developing economies. In the Taiwanese port city of Kaohsiung, Asia’s first electric ferry entered into service last year with the goal of reducing diesel usage by 65,000 liters and CO₂ emissions by 170,000 kilograms annually.

Across the sea in Hong Kong, Star Ferry, the company that operates the old-fashioned vessels that connect Hong Kong Island with Kowloon across Victoria Harbor every six minutes for little more than a quarter, is gradually shifting toward greener operations. In 2016 the company’s World Star, which works as a tourist ferry in the harbor, was converted to a diesel-electric system.

Star Ferry’s Jacky Ho says, “The main advantage of the conversion is environmental friendliness, and it has been well received.” Black smoke reportedly dropped 68 percent while nitrogen oxide emissions declined 69 percent. Further improvements could still be made, however, but there’s the issue of cost. Ho adds, “The reduction in fuel consumption is not significant, and the converted ferry requires higher maintenance costs.”

The Cost Challenge

As engineering and design firms along with ferry operators around the world pursue green solutions, ABB’s Silva stresses that, ultimately, governments need to push them harder.

“The challenge for making ferries more environmentally friendly is definitely not related to technology,” he says. “To make more ferries take the environmentally friendly route, we need visionary politicians and government institutions to create bold policies that will encourage shipowners to replace conventional technology onboard their vessels with solutions that dramatically reduce their environmental footprint and ultimately enable zero-emission operation.”

Silva suggests the possibility of governments providing financial support for newbuilding projects as one means of advancing green ferries. Judging by current projects around the world, while important renovations are being made to older ships, some of the most promising technologies like enormous batteries and silent ships are found only on newbuilds.

If governments and companies keep up the pace, passengers sailing on the ferries of tomorrow will no longer have the wind at their backs, but rather electricity. – MarEx

University of Hong Kong visiting scholar Mia Bennett is a frequent contributor on environmental issues.