bound4blue’s Pwind calculation validated by Loyd’s
Lloyd’s Register (LR) has validated a new calculation methodology developed by bound4blue, giving shipowners a reliable way to harness the regulatory and financial benefits of wind propulsion.
Installing wind-assisted propulsion systems always has some positive effect in reduction CO2 emissions and contributes to green image of fleet owners. But off course it is only economically feasible when the calculated benefit is accepted under regulatory reduction targets and incentive schemes. Therefore the calculation methods must comply with standards from IMO and FuelEU and be validated by a maritime classification society. Bound4blue, a manufacturer of wind-assisted propulsion systems has received validation from Lloyd’s Register for their approach.
From the Lloyd’s Register press release:
The validation of bound4blue’s ‘wind propulsion system force matrix calculation methodology’ gives shipowners a robust, credible and compliant means to calculate the Pwind value of installations.
Pwind is the propulsive power from a wind-assisted propulsion system (WAPS), used to reduce a ship’s regulatory burden and support environmental compliance. Under International Maritime Organization’s (IMO) MEPC.1/Circ.896, it can be deducted from engine power in Energy Efficiency Existing Ship Index (EEXI) and Energy Efficiency Design Index (EEDI) calculations, and it contributes to the Wind Reward Factor in FuelEU Maritime, easing greenhouse gas targets and lowering costs.
The force matrix, which represents the thrust characteristics of a WAPS under various wind conditions, must be installation-specific (considering both sail-to-sail and ship-to-sail aerodynamic interactions) and validated by an independent verifier.
LR’s validation confirms that bound4blue’s approach, which combines advanced computational fluid dynamics (CFD) modelling with wind tunnel test results, meets IMO standards.
With this validation, shipowners can now calculate Pwind without the need for full-scale testing, reducing costs and speeding up project timelines. The approved CFD-based method can be used for future eSAIL® projects, so shipowners can quickly obtain verified Pwind values for compliance, supporting wind propulsion adoption.
The first installation to benefit from this validated methodology is the juice carrier M.V. Atlantic Orchard, which operates with four bound4blue eSAILs® and is chartered by Louis Dreyfus Company (LDC) and owned by Wisby Tankers.
Source: Lloyd’s Register
Image: screenshot from the IMO MEPC.1/Circ.896 document
Pwind explained for laymen
The press release above refers to complicated calculations. We were overwhelmed by all the formulas in the MEPC document and started some online research. We came across an article by a French mathematician on the blog of ‘Calculatrice en Ligne’, a provider of online calculation and simulation services. Apparently, the author was triggered by the same press release. It is an extensive article, but a lot more accessible then official documents cited above. Click here for the original article in French. For a Google translation, click here.
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