They mean they don't have the capacity to offload all the waiting tankers due to the on-shore storage tanks being mostly full. The ships sitting idle costs mone

They mean they don't have the capacity to offload all the waiting tankers due to the on-shore storage tanks being mostly full. The ships sitting idle costs money. In an effort to stop the bleeding from the idle tankers, they drive the costs of the fuel down in an attempt to lower the supply in the on-shore tanks so they can offload the waiting tankers. In a normal scenario they would have enough slack in the on-shore storage to absorb the ebbs and flows of incoming tankers and outgoing usage without resorting to idle tankers in the ocean.