Emission Testing Services

EMISSIONS MEASUREMENT PROTOCOL FOR FERRYBOATS

Client: San Francisco Bay Water Transit Authority, San Francisco, CA

The San Francisco Bay Water Transit Authority was created and charged by the Legislature with developing a viable plan for a comprehensive regional public water transit system for the Bay Area. To ensure that this plan and the associated environmental impact report (EIR) and environmental impact statement (EIS) adequately accounted for pollutant emissions from both existing ferries and the new ones to go into service, it was important that these emissions be measured accurately and under representative conditions. EF&EE was contracted by the Authority to develop a suitable protocol for measuring ferryboat emissions, and then to carry out a series of emission measurements on ferryboats using this protocol. Experience gained in performing these tests was then used to refine the test protocol. The resulting test protocol will be used in the future both to quantify emissions from existing ferries and to specify emission limits for future ferryboats.

The test protocol developed made use of EF&EE’s RAVEM system, while leaving open the possibility of other test methods. Pollutants measured include NOx, CO, CO2, methane, VOC, ammonia, N2O, and carbonyls. Methane and aldehyde emissions are a concern for natural gas engines, and ammonia and N2O are concerns for selective catalytic reduction systems, both of which were considered likely candidates for future ferryboat propulsion systems.

Emission measurements were performed on three diesel ferryboats operating in San Francisco Bay: M.V. Mare Island, Peralta, and Golden Gate. Mare Island and Peralta are relatively new, "fast" catamaran vessels, while Golden Gate is an older, monohull design. Golden Gate was tested twice, once when operating on regular California diesel fuel, and once using PuriNOx®, a water emulsion fuel. In each case, emission measurements were successfully carried out while the vessels were in normal service, carrying passengers on San Francisco Bay. The test results showed that baseline emissions from these ferries were less than the emission factor estimates commonly used for inventory development. The effects of the emulsion fuel were mixed – decreasing PM emissions at high load, but increasing emissions at idle and light loads.