One giant cargo ship emits nearly as much pollution as 50 million cars. That was the jaw-dropping nugget in a Guardian story way back in 2009. For years, there has been a movement to introduce alternative fuels to the world’s maritime industry.
Almost all ocean-borne shipping now runs on heavy oil or diesel fuel and has done so since the conversion from coal in the early part of the 20th century. Both these fuels have high carbon content, however, and have also been targeted for emission of nitrous oxide and sulfur dioxide. Both international agencies and the Environmental Protection Agency are starting to crack down, which has spurred interest in the substitution of alternative fuels.
Maritime shipping now absorbs about 5 percent of our oil output, including oil imports. There’s no particular imperative to cut back on this consumption, but the effort to reduce our oil dependence may be able to piggy-back on the larger effort to cut down on pollution and emissions. All the alternative fuels being mentioned are based on electricity or natural gas.
What is particularly intriguing is the possibility of methanol as an alternative fuel. Methanol as a substitute auto fuel has been stymied by the EPA’s refusal to endorse it for transportation, even though it does not differ significantly from ethanol or regular gasoline. But this restriction does not apply to methanol use in ferries and ocean-going cargo ships. The introduction of methanol in maritime traffic could pave the way for its use in our automobiles as well.
The International Maritime Organization (IMO) and the EPA have both introduced restrictions on NOx gases emanating from cargo ships in port areas, known as Emissions Control Areas (ECAs). These have been met by the manufacturers introducing internal engine modifications. But sulfur regulations will be different. Both the IMO and the EPA introduced sulfur standards for port areas in 2010 and lowered them to maximum 0.1 percent sulfur this year. The regulations will be extended globally in 2020 or 2025.
Meeting these standards has meant a) switching to low-sulfur fuel, or b) introducing on-board sulfur scrubbers. Both of these options are very expensive. This has prompted a search for alternative fuels that do not contain sulfur. Both natural gas and methanol qualify.
Liquid natural gas (LNG) was first utilized by LNG carriers in the 1960s. Because these ships were already carrying the fuel, conversion was easy. The first LNG-powered ferry was built in Norway in 2000. In the ensuing decade, 20 more LNG-powered ships were built, many of them operating in Norwegian waters. Since 2010, the growth of LNG-powered ships has accelerated, resulting in 59 ships in operation today and another 80 under construction and planned for delivery by 2018. The size of the ships has increased as experience has been gained. Most of the newly built vessels will operate in northern Europe and North America, but some will be put afloat as far away as South America and China.
There are some disadvantages: LNG tanks are roughly 3-4 times the size of oil tanks and can increase the cost of a new vessel by up to 30 percent. Methane leakage can also be a problem that cancels any advantage gained in carbon emissions. But technological improvements could minimize these problems.
Biofuels are another possible substitute, and among these is methanol. In “The Fuel Trilemma: Next Generation of Marine Biofuels,” a study published in April, DNV GL Strategic Research & Innovation says methanol can be made from coal or natural gas but also suggests black liquor, the by-product of the pulp and paper industry. “Interest in methanol as a shipping fuel increased after Stena Line’s decision to retrofit one of its vessels for using methanol, as a solution to low sulfur fuel requirements,” the report says. Methanol has several advantages over LNG. “[T]he cost of retrofitting for methanol is much lower than the cost of retrofitting for LNG, due to the properties of the fuel.” The same holds true for automobiles, of course, where LNG requires an entirely new engine and on-board storage tank while methanol can simple be fitted into our current infrastructure.
DNV maintains that the many ways of producing methanol all promise a low carbon footprint. “Another interesting possibility for producing methanol with a low carbon footprint is directly from hydrogen by electrolysis run on geothermal electricity and CO2 from the same geothermal source. This is currently being tested in Iceland.”
Finally, DNV considers the possibility of running boats – mostly localized ferries – on electricity. “The first fully electric ferry will enter service in Norway’s Sognefjord during 2015, in a cooperate effort between Siemens and the Norwegian shipyard Fjellstrand. It has a capacity of 360 passengers and 120 cars, and produces no direct emissions as the power is generated from the shore-based grid.”
Powering ships undertaking longer voyages than short ferry runs, of course, will require power packs on the scale of Tesla’s home storage devices. But a great deal of the world outside the United States runs on ferries, and the possibilities for reducing oil consumption here are widespread.
So world maritime travel offers many opportunities for reducing our dependence on oil. And the most interesting possibility is the introduction of methanol – either from natural gas or biological substrates – as an easy substitute for oil-based fuels.