LONDON/MADRID, Oct 17 (Reuters) - Dozens of ships carrying liquefied natural gas (LNG) are circling off the coasts of Spain and other European countries unable to secure slots to unload because plants that convert the seaborne fuel back to gas are full. There are also LNG vessels at anchor near other European countries which could mean dozens more are waiting, one source with knowledge of the situation said. "If more cargoes were being produced companies might not be able to leave their ships waiting around so long," he said. If the backlog is not cleared soon those ships may start looking for alternative ports outside Europe to offload their cargo. The lack of pipeline infrastructure means that this gas cannot be transported to other European countries.

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