Alternative technologies for marine
fuels and energy sources have great potential for improving the environmental
footprint of waterborne commerce. Innovations are providing new policies,
products, and methods to reduce emissions. These innovations include:
• New international and national standards for conventional marine
• New, innovative fuel concepts.
• New exhaust remediation technology.
• Shore-to-ship alternative powering techniques.
• Ocean-based renewable energy.
Large, slow-speed diesel engines
currently predominate in the powering of cargo ships, principally burning heavy
fuel oil (HFO). Of all the fuel types used by cargo ships, HFO result in
significant levels of certain pollutants, such as SO2 and sulfate particulate
matter, due to its relatively high sulfur content. Typical ship exhaust
contains the following pollutants, leading to adverse effects on human health
and climate change:
• Nitrogen oxide (NOx).
• Sulfur oxide (SOx).
• Carbon monoxide (CO).
• Carbon dioxide (CO2).
• Particulate matter (PM).
• Other greenhouse gases (GHGs).
Ship emissions are being reduced
through use of non-conventional fuel to meet new International Maritime
Organization (IMO) and U.S. Environmental Protection Agency (EPA) fuel
standards. Some of these fuels include liquefied natural gas (LNG), methanol,
and biofuels. In addition, other strategies are becoming available to reduce
emissions, such as exhaust gas scrubbers and cold ironing (providing electrical
power in port).
Biofuels are an interesting option,
although fuel availability and uncertainty about long term engine maintenance
may affect its application. Exhaust scrubbers, particularly those using salt
water, may allow for continued use of high sulfur fuels but could shift an air
pollution problem to a water pollution problem and would not help with pending
NOx control requirements. Cold ironing or shore power is being
considered at a number of ports where infrastructure costs are balanced with
benefits. Cold ironing has been implemented at military bases, several
California ports (driven largely by a California Air Resources Board regulation
that addresses hoteling emissions for ships at berth), Seattle, New York, and
in several Canadian ports (Prince Rupert, Vancouver, and Montreal); these
systems mitigate dockside port emissions, but do not address emissions while
the vessel is underway. LNG-fueled barges
can also be used as an alternative power sources for vessels at-berth, at
present this technology is primarily used to comply with at-berth fuel
regulations in Europe.
of these technologies are also applicable for harborcraft, including assist
tugs and ferries, who may be operating propulsion and auxiliary engines that
are many decades old. Benefits from emission reductions and fuel economy may
also be realized from these smaller vessels.
There has been a lot of attention
recently on LNG due to current pricing of natural gas and generally low
emissions associated with this fuel. Lloyd’s Register estimates that LNG could
reach 11% share of marine fuel usage by 2030. The use of natural gas as a
transport fuel has been growing steadily over the past decade. This increased
activity is evident in many different spheres, including industrial
initiatives, public investment in new infrastructure, statements by technology
providers, new government policies and incentives, and emerging research
projects. Developments in the deployment of LNG-powered vessels and in the construction
of new LNG refueling and import infrastructure have been steady since 2006.
Three manufacturers—Rolls-Royce, Wärtsilä, and MAN—have developed different LNG
engine technologies for marine applications. Spark-ignited, lean-burn engines
allow the gas to be mixed with an excess of air before passing through the
intake valves, more completely combusting the fuel and reducing efficiency
losses. Dual-fuel diesel engines, which can run on LNG or distillates, are
gaining traction, but technological improvements are needed to address methane
slippage from duel fuel 4 stroke engines.
The infrastructure for LNG is being
ramped up to meet the demand for these ships. Norway has already developed a
system of small-scale LNG production and storage facilities that supply ferries
and other working ships. New LNG shipbuilding contracts around the world are
now aligned with some installation of bunkering facilities to provide the fuel.
Over the longer term, several governments have bigger plans for LNG in the
maritime sector. For example, the European Commission launched an ambitious
plan to have 139 LNG refueling facilities for seagoing and inland vessels in
the 2020–2025 timeframe. Yet, LNG as a
marine fuel is still in the fledgling stages. The following LNG ships are in
operation or planned:
• About 30 operating LNG-powered cargo ships (ferries, platform supply
vessels, merchant ships, coast patrol, etc.—mostly in Norway), with about 25 on
order (including in Canada, Finland, Norway, Sweden, and the United States).
• About 400 operating LNG oceangoing vessels, with an additional 50–100
planned for 2015 through 2018.
• A few large oceangoing vessels in Europe and a handful of container
ships in the United States to be delivered between 2015 and 2016.
As a result of these numbers,
forecasts are that the growth of LNG-powered ships is unlikely to play a major
role in the shipping market in the next decade. Invariably, many barriers to
the development of LNG as a shipping fuel will have to be addressed sooner rather
Importantly, the impact of these
non-conventional fuels need to be considered along the entire fuel cycle –
i.e., from fuel extraction to use. Some
fuels that may be environmental ‘winners’ at the ship stack may not be such
when emissions from extraction, refining, and delivery are considered.