Real question: What is the largest tidal power installation in the world? Why do we see so little of it?

I think there's a 2MW test turbine off Scotland which I think is the biggest in the world.

https://www.bbc.co.uk/news/uk-scotland-north-east-orkney-she...

Just not as cost effective as wind, which got to piggyback of onshore turbine development.

We don't see large tidal power installations because they are not every economical so far. In theory there's a lot of energy to be won, but the salt water causes corrosion issues, and maintenance gets expensive quickly

This is a very good post. I never before considered the issue of corrosion. To that point, does this also affect offshore wind power generation (turbines)? I guess the difference will be: the turbine is not underwater!

offshore wind is much less effected because all the complicated parts are 100 feet up, and much easier to partially seal.

on the other hand its 100% reliable and needs no fuel, does notndepend on drought, etc.

But the UK has HVDC line to norway right?

Yes it does, in fact the UK is in the process of building many more HVDC interconnectors (see table in 3rd section of page) https://www.ofgem.gov.uk/energy-policy-and-regulation/policy...

Is wind power even worth the investment? From disposal issues to wind turbines killing birds and bird habitats to sheer unreliability, wind seems to have a ton of issues.

You wrote "disposal issues": As I understand, the current generation of windmill blades are not recycled. Rather, they are sent to landfill (at least in United States -- can someone please comment for other countries that they know about? UK?). Two things to consider: (1) Fiberglass mostly inert and safe to bury. Please correct me if wrong. (2) Can future designs be recycled? I assume yes.

wind mills kill way fewer birds than mining does. wind has a few incredibly minor issues, but so does everything, and wind is green and cost effective.