"Biodiesel can be used in both new and existing ferries. However, introducing biodiesel in ferries can be challenging. Biodiesel has a higher acidity than regular marine fuels. This can result in slight problems for older engines that have poor rubber quality in hoses and sealing. In new engines with normal wear proof material, biodiesel according to the standard EN14214 should work fine. Before using biodiesel, storage tanks should be cleaned thoroughly." (Quoted from paper)