> V2G can absolutely make some contribution for very short-term fluctuations (such as for from Nuclear ramp up/down cycles, but the capacity several orders of magnitude too small to compensate for a few weeks of almost no wind in the North Sea.

As noted we know efficient ways to reduce intermittence-induced production variability.
If you are interested in all this the very scientific study described by the article I refenced is of interest.
Note that other studies deliver similar results, see "How synchronous is wind energy production among European countries?" -- Monforti, Gaetani, Vignati). Those conclusions are sound for other continents, for the US see "Is it always windy somewhere? Occurrence of low-wind-power events over large areas" (Handschy, Rose, Apt), for China see Liu, Xiao Wang, Dai, Qi "Analysis on the hourly spatiotemporal complementarities between China's solar and wind energy resources spreading in a wide area"...

> The extreme price fluctuations

Yes, the context (economic crisis, energetic transition, international tensions...) isn't keen. I didn't know how hard it hits in Norway. In many Western nations it hits very hard but this is hidden from public sight by throwing public money at the problem (usually by sacrificing usually perceived energy taxes in order to create provisions or even pay for the current high market price), leading to more debt and therefore higher taxes (as usual the taxpayer and consumer will nonetheless pay, and more because the very government has a cost, burning part of taxes).

> the reservoirs in the hydro systems are already unusually low

Yes (climate...), and the planners have to keep some reserve in order to preserve necessary margins (emergencies and follow-up).

> Denmark should expect that at some point soon, Norway will shut down exports until the situation has normalized.

A huge grid offers more potential commercial partners, and the probability of an extreme "nobody is able to sell" case gets lower and lower.

> What happens to Danmark's electricity market if they are no longer able to import power from Norway and Sweden?

There are many factors: how much parties can plan for it in advance, find others sellers, curtail, backup... The composition gives the net result.

>> This is mainly a financial matter. A 'cooperation' achieved thru a market

> You would be right if Norway were able to coordinate that internally in ways that did not hurt the population. But in Norway, since electricity is used for heating (and it is cold here). That would have to mean a setup where households were able to buy electricity at prices close to the historical prices

We can predict a fair part of the parameters, therefore many cases are manageable. Even worst-case scenarios, leading to throwing public money at the problem, are in a way useful because they trigger adequate reactions (innovation...). Ways to cut down a huge part of heating-related needs are known, for example by enhancing thermal isolation or heating buildings in "anti-frost" (no freezing) mode while wearing heated clothing.

> But being a full member of the open energy market simply doesn't work for Norway at these price levels. It's kind of being members of an open market for food when your population is starving, even if you're a net exporter.

Yes, there always is a limit, even for our ability to counter limits by multiplying ways to cope. Compare various approaches merits is difficult, for example France touted its nuclear fleet as a sure way to be autonomous but now detects corrosion inside pipes, has to temporarily shutdown reactors (load factor now floats around .7) and therefore was recently very happy to import electricity from Germany (which is usually mocked because "wind & solar are intermittent,: Germany needs France"...). Moreover France imports most of its uranium from Kazakhstan (one may imagine Putin's going full LOL ahead upon reading that "France loves not to depend upon other nations").

> The prices of nuclear is caused by political choices. With rational (or only sightly paranoid) regulations, nuclear would be a lot cheaper.

Political choices are only part of the problem, and apparently not part of the main ones (there is a very interesting report about the French Flamanville-3 case, named the "rapport Folz", however it's in French I could not find any English version). Not being paranoid probably increases the probability of incident/accidents (contesting this is saying that some safety-related new specifications are totally useless: this is a bold statement), and on the long-term reducing the amount and patent effects of boo-boos, even at a non-negligible cost, may be the best bet when it comes to public opinion. This is not necessarily badly-invested money and time.

> there are a lot more pro-nuclear people now, than when I advocated for nuclear 15 years ago.

This seems globally true, however the amount of people willing to see a reactor installed in their vicinity rather than wind turbines in the ocean is low and stable.

>> A continental mix reduces this need.

> Not below "several days"

At continental scale several days without a fair part of the baseload and peaks, starting with storage at low charge, with not enough curtailing and backup capacity? I doubt so.

> long distance energy transfers are expensive

Indeed, however the huge grid is justified whatever the type of source: even going full-nuclear would justify it, for safety (see the current French 'corrosion' case) and to be able to use more sound sources (avoiding production units which burn fossil fuel). As showed this is already launched ( https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta... ) and will very be be further developed ( https://en.wikipedia.org/wiki/European_super_grid ).

The impact of renewable sources is here limited to dimensions, not the very existence of most lines, therefore the real cost (specific to renewable sources) is limited, and way below many models proposed by nuclear or fossil industries.

This limited specific investment will be recouped thanks to a way lower LCOE, as producing electricity thanks to renewable sources is way cheaper than using nuclear (and getting more and more so).