Washington State Ferries (WSF) is exploring an option to use liquefied natural gas (LNG) as a source of fuel for the Issaquah Class ferries. LNG is used world-wide and provides an opportunity to reduce fuel costs, and better the environment by decreasing emissions.
What is LNG?
In its gaseous state, LNG is the same fuel used to heat our homes and cook our meals. LNG is natural gas that has been cooled to -256 degrees Fahrenheit, at which point it is condensed into a colorless, odorless, non-toxic and non-corrosive liquid. In its liquefied form it occupies 1/640th of its original volume, which makes it easier to transport and store.
Saving money, cleaner environment, energy independence
WSF burns more than 17 million gallons of fuel each year. Fuel is our fastest growing operating expense. Fuel represents 23 percent of the FY13-15 operating budget, compared to 11 percent in FY00-01. The fuel cost savings moving from diesel to LNG is approximately 40-50 percent at today’s pricing.
Operating WSF's six Issaquah Class vessels with LNG would significantly reduce emissions when compared with today's use of ultra-low sulfur diesel fuel. WSF's Air Emissions Model predicts emission reductions as follows:
- 89 percent reduction in particulate matter
- 61 percent reduction in nitrous oxide
- 28 percent reduction in carbon dioxide
- 59 percent reduction in sulfur dioxide
Use of natural gas in transportation has been steadily increasing for the last decade. LNG is fast becoming a transportation fuel for transit buses, semi-trucks and ferries.
- Since 2000 the Norwegian government has allowed the construction and operation of LNG passenger vessels. There are currently 20 car and passenger ferries operating in Norway that are fueled by LNG.
- Both BC Ferries and Staten Island Ferries are studying options to retrofit their vessels from diesel to LNG fuel.
- The Quebec Ferries Company has contracted for three new LNG ferries.
- There are LNG passenger vessels currently under construction or in design for service in Argentina, Uruguay, Finland, and Sweden.
U.S. examples of LNG used in public transportation
Other LNG resources
In Dec. 2011, WSF received conceptual approval from the U.S. Coast Guard to retrofit the propulsion system with new engines on the six Issaquah Class ferries to use LNG as a source of fuel. In 2012, WSF selected Det Norske Veritas to complete a safety and security plan, risk assessment, and operational manual for converting to LNG. DNV is a classification body that has been involved in developing international standards for the use of LNG in passenger vessels. On Nov. 18 WSF submitted the a Waterways Suitability Assessment (WSA), which includes a safety and security assessment and risk management plan, to the U.S. Coast Guard for approval. The WSA concluded that the LNG proposal is inherently safe with risks as low as reasonably practicable.
Renderings of LNG tanks on an Issaquah class ferry (click to enlarge)
Pending U.S. Coast Guard approval and funding, WSF could begin the first conversion of an Issaquah Class ferry as early as 2016. Below is the status of two key, parallel efforts:
- Safety and security assessments – The submission of the WSA marks the official starting point of the U.S. Coast Guard’s review process. WSF expects the Coast Guard to issue a finding regarding the LNG conversion proposal in 2014.
- Design/build LNG propulsion system – In Fall 2012, WSF issued a request for proposal (RFP) for the retrofit of its six Issaquah class ferries. The RFP requires the contractor to purchase and install all the required equipment and get all the required approvals to allow the vessel to obtain a certificate of inspection from the U.S. Coast Guard for operation with LNG as a fuel. Proposals are presently being evaluated.
WSF Communications Manager