MYSTERY will continue to shroud the availability of quality and stable compliant 0.5 per cent sulphur fuel blends even after IMO 2020 comes into force in January, reports London's Vessel Performance Optimisation (VPO) journal. Uncertainty is exacerbated by the current lack of compliant fuel blends, said Hong Kong's quality assurance agency Intertek's global technical manager Michael Green. Mr Green said that it is unlikely that a clear direction will be found until such fuel blends have been operating in the market for several months. But shipowners and operators should prepare their fuel management systems now to reduce contamination, incompatibility, and operational issues, he said. To prepare for bunkering new fuels, shipowners and operators must ensure that their ships' tanks are fully cleaned and free from any traces of non-compliant fuel. If a new 0.5 per cent fuel blend is contaminated with remnants of HFO, a shipowner could find itself inadvertently not complying with IMO 2020. Furthermore, the contamination could lead to fuel instability and a clogging of the filters and separators with sludge, he said. Exacerbating this issue is the fact that each 0.5 per cent fuel blend will come from multiple refinery streams, meaning that a 0.5 per cent sulphur fuel bunkered at one port will be of a different chemical composition to a 0.5 per cent sulphur fuel bunkered at another port.