Impact of Algae Biofuel on In-Use Gaseous and Particulate Emissions from a Marine Vessel

In-use emission rates for a marine vessel operating on hydrotreated algae biofuel are reported for the first time. Emission measurements were made on a four-stroke marine diesel engine from a Stalwart class vessel to compare the emission profile from burning ultra low sulfur diesel (ULSD) to a 50:50 blend of ULSD and algae biofuel (A50). In-use emission measurements followed the International Organization for Standardization (ISO) 8178-4 D2 certification test cycle protocol. Particulate matter (PM 2.5 ), nitrogen oxides (NO x ), carbon monoxide (CO), and carbon dioxide (CO 2 ) were sampled in accordance with the ISO 8178-2 protocol for each mode of the test cycle. Switching fuel from ULSD to A50 resulted in significant ∼35% lower PM 2.5 emissions for 25 and 50% load and an overall weighted PM 2.5 reduction of ∼25%. Overall reductions of 30 and 20% were observed in elemental carbon (EC) and organic carbon (OC), respectively. PM 2.5 was dominated by OC (77–94%) for both fuels. NO x emissions were reduced by ∼10% on switching from ULSD to A50. Overall, the emissions of CO 2 and CO were reduced by 5 and 18%, indicating a slight improvement in fuel economy for this engine while operating on A50.