OSES2018 Theme: “The new ambition for offshore energy” The OSES conference series addresses offshore energy systems – with major emphasis on the word “systems”. For several decades research and development has been conducted in discrete silos on offshore wind power, coastal wind power, tidal range plant, tidal stream generation, wave energy conversion, floating PV arrays, osmotic energy conversion using salinity gradients, thermal power generation using ocean thermal gradients, uranium extraction, energy storage over timescales of seconds/ minutes/ hours/ days, electrical power transmission offshore, energy vectors suited to offshore energy movement and, of course, the commercial and policy approaches that make it feasible for private companies to spearhead advances in the technical areas. Things had to change – and they have. OSES2018 sustains the tradition developed annually since OSES2014 of bringing together researchers and industrialists working to exploit offshore energy.