DESIGN FOR PERFORMANCE
RESEARCH PROJECTS DEEPENS WIND-ASSIST DESIGN INSIGHT Researchers at MARIN are examining the regulatory framework and design maturity of wind-assist technologies
8 MV Ankie after installation of the extended VentiFoils
Over 20 companies participated in the WiSP1 project that evaluated the potential fuel savings of wind-assisted propulsion and finished in 2021. Emissions savings analyses from currently sailing ships range from roughly 5% up to 15% as a yearly average, but that is just the beginning, says Rogier Eggers, Senior Project Manager at MARIN. Now a follow-on project WiSP2, led by MARIN and ABS, is focused on evaluating the potential for greater savings as the technologies mature. WiSP1 saw analysis mainly on the 5-15% wind-assisted scenario that was submitted to MEPC76 (June 2021) by Comoros and RINA. A follow-up informal working group led by Germany, also with other input, resulted in a revised guide line for the prediction of wind propulsion performance under EEDI and EEXI: MEPC.1/Circ.896. At that time, Eggers says a controversial change was also introduced: this guideline allows for the calculations to only consider the 50% best winds when determining EEDI and EEXI values. The impact of this is now also being investigating in WiSP2. “This offers a big incentive. An incentive may be considered appropriate. Other energy saving devices (e.g. air lubrication) is only to be assessed at one speed and loading condition and in calm seas whereas wind propulsion was to be assessed using overall global wind conditions. Ships with wind propulsion are more likely to sail in better wind conditions. However, at the same time, the implemented incentive is very large. Also, some device types which are very selective with the wind conditions that they can work with may be favoured more than other devices that present a wider range of usable wind conditions. In short: we feel more work is needed, and we will do that in WiSP2”
28 | JULY/AUGUST 2022
For efficiency gains of 5% to 15%, there is not a lot of further discussion needed on ensuring ships’ operability in demanding conditions, says Eggers, who has been heavily involved in both projects. “Ships generally still behave the same way as a conventional ship, but as you go to more substantial proportions of wind power being used, more discussion is necessary. For instance, significant yaw moments are introduced that depend on the wind condition. In order to counteract these loads, steering systems will need to constantly keep the ship in balance. Enough reserve capacity needs to be ensured for manoeuvring and course keeping in wave, although it is mentioned that some wind propulsion systems may also in fact help steer the ship” Current regulations were never intended for this scenario. In the updated circular for EEDI and EEXI there is a disclaimer that there would be a bias in the current regulations if they were applied to more substantially more wind power onboard, and correcting this is a focus area for WiSP2, along with other regulations, such as the IMO manoeuvring standards. Ultimately, the aim of WiSP1 and now WiSP2 is to prove what kind of fuel savings shipowners can achieve, enabling them to make informed investment decisions. A study by CE Delft on the market potential for wind propulsion found that a major barrier to uptake is the shortage of transparent and independently verified information and methods to predict the performance of wind propulsors. Other barriers identified were a lack of sufficient practical examples and tailor-made work to demonstrate compliance with statutory and class rules and regulations. “We have seen some really large savings being predicted by developers, followed by still larger claims by their
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