As other say: it is converging to Hawaii-prices, but most of that is Taxation. In Denmark, the policy has been to put taxes on resource usage in the later years and not only on income. In this case the resource usage is on fossil fuels.
The slight problem with that model is that in principle, it should be cheaper when the energy is green, and more expensive when it is not. But the state has come to rely on the tax, so now it is a bit murky what it is really for.
Denmark's electricity price is the highest in the EU "when you count in taxes and VAT, which go to produce other useful outcomes. However, Ireland together with the UK has the highest energy prices excluding taxes, closely followed by Cyprus and Spain. Interestingly enough, three of these are islands.
It would be interesting to see these prices without subsidies, as the energy market is pretty global and these big differences must come from something else, I think."
Looking at https://en.m.wikipedia.org/wiki/Synchronous_grid_of_Continen... and combining that with your remark, I would guess the electricity market isn't "pretty global". Yes, you can ship coal and oil about everywhere, but there seem to be economies of scale in larger networks, especially if your grid spans time zones (people switch on their stuff at different times in GMT), and Europe's does that.
Of the four you mention, three aren't connected to that grid, and I would guess the link with Spain doesn't have sufficient capacity to even out peaks and troughs in Spanish demand (http://ses.jrc.ec.europa.eu/power-system-modelling does show a fairly thin line between France and Spain, both large countries in population)
The above is 100% educated GUESS. Corrections welcome.
The slight problem with that model is that in principle, it should be cheaper when the energy is green, and more expensive when it is not. But the state has come to rely on the tax, so now it is a bit murky what it is really for.