The cheap part of bonded bunker fuel is the tax base. The same parcel of fuel oil, if cleared under the bonded regime and supplied to an internationally trading vessel, carries no consumption tax; once it is sold into the domestic market it falls under the refined-oil tax schedule. That line defines the cost floor for Zhoushan and the outer Shanghai port to compete with Singapore for ship calls.

Now a second layer sits on top of that structure. Bonded bunkering of green marine fuels — LNG and methanol — has widened from a handful of pilot ports to more hubs. For ship owners the bunkering choice no longer turns only on the discount; it now weighs whether a port can top up green fuel in the same call instead of queuing again at the next port.

For SNSUC's seven transfer-grade barrels the read-through is in the freight line. Part of the delivered cost is the bunkering expense at the destination or transshipment port. As Zhoushan and the outer Shanghai port build bonded bunkering capacity, Middle East-to-Far-East vessels refuel more smoothly at the Far East end, which trims both the cash tied up in the voyage and the demurrage risk.

One caveat: wider pilot access is not a blanket opening. Bonded green-fuel bunkering still runs through strict marine-fuel designation, quantity verification and the customs supervision chain. Blends that fall outside the designated scope revert to the consumption-tax logic. Price the voyage on the pilot terms, not on the assumption that the exemption is universal.