The argument is that vibrations of the wind power plants at sea disturb the whales.
Paying for the gas itself would not be an externality. Externalities are for example the worldwide damages caused by extreme weather which is caused by climate change, health problems caused by air pollution or the usage of clean water for cooling
> The argument is that vibrations of the wind power plants at sea disturb the whales.
It's an argument that's always reeked of whale shit to me. If they really cared about marine sound pollution they'd go after super yachts first.
Normally, I'd agree, but in this age of massive corruption, you need to be careful figuring out who the stakeholders are. The purpose of these new fossil plants is not to produce electricity. Their purpose is to line the pockets of the ultra-wealthy people building them, and of the politicians accepting bribes to get them built.
Fueling the power plant is an externality for the people building the power plant. You could argue that it increases their costs, but these things are monopolies, with prices set by bought-off politicians. The plant + fuel costs much more than renewables (so ratepayers get screwed), but I'll wager the plant without fuel is still a bit less than solar or wind construction.