Specific Fuel Consumption [g/kWh] for Marine Engines
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Specific Fuel Consumption (SFC) of marine engines ranges between 155 and 225 g/kWh on optimal load settings, which are typically around 85% Maximum Continuous Load (MCR). Two key factors for marine diesel engines are engine speed (low, medium, high) and engine type (two-stroke or four-stroke). Specific fuel consumption increases greatly at low power (30% Pmax) and dramatically at idle (7% Pmax). When an engine is idling, its specific fuel consumption can increase by a factor of two. At the same time, idling engines are prone to stalling, clogging and require a significant amount of maintenance, potentially requiring service once every three weeks. For these cases, Sustainable Ships recommends load levelling by means of electrical energy storage.
This blog is used as a reference for estimation fuel consumptions and emission savings for the Decarbonizer. it is subject to continuous change.
How the tool works
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Low engine loads
There is little to no publicly available data for engines running at very high loads or idling, i.e. between 1-10% load. This is almost never measured when engine test certificates are prepared. From experience ‘in the field’ it is known that SFC can go as high as 1.500 [g/kWh] at 1% engine load for large-sized medium speed marine engines. For smaller sized auxiliary engines, this could be even higher but Sustainable Ships has so far not met anyone who knows more on that topic. It is known that smaller sized engines easily consume 1 [kWh/liter] at 10% load.
Rules & Regulations
Engines are heavily subjected to increasingly stringent rules and regulations, subject by IMO and thus class. Especially NOx tiers are relevant. Click on the below rules and regulations to learn more.
References
Hyperlinks and downloads for premium users only
IMarEST - Design of propulsion and electric power generation systems Douwe Stapersma Hans Klein Woud
HOK Marineconsultant ApS - Energy demand and exhaust gas emissions of marine engines
Douwe Stapersma - TU Delft Main propulsion arrangement and power generation concepts
MIT - Diesel engine continued
Wikipedia - Brake specific fuel consumption
Wärtsilä 46F - Marine Engine Product Guide
RED targets supply side - production - of fuels in the EU, aiming for a 40% energy share from renewable sources by 2030.