Ireland is a net energy importer who imports electricity from Great Britain. She, in turn, often imports from nations including France, Holland, and Denmark, who use coal power.

As such, it's not really the whole story to call Ireland, "coal-free". It's the same as America outsourcing heavy manufacturing or chemicals to China and claiming environmental victory. It's true in a narrow construction of the concept; it does reduce the burden on one's own country. It is false in the sense of one's contribution to the global commons and externalizes those externalities previously more internalized. It is, in other words, a shell game. Ireland's dependence on imported energy continues to rise and the number continues to tick up on the books of other nations and down on hers, with her people paying the "guilt premium" associated with this accounting trick. They're not exactly dirty grids, but the fact remains, Ireland still relies to some extent on coal.

Also note that, though she is building OCGTs and fast CCGTs elsewhere, she converted Moneypoint not to gas but to heavy fuel oil. HFO is quite dirty stuff, only a dozen or so per cent cleaner than the coal it replaces per Ireland's own EIS. This is likely influenced by the fact that the plant was specced to burn some of the cleaner thermal coal on the market, largely from Glencore's Cerrejon mine, with pretty low sulfur and ash relative to others. So, the delta from relatively clean coal (excuse the expression) to some of the dirtiest oil; large boilers like that are likely burning No. 5 or 6, aka bunker B or C in marine. Not sure if you've ever seen (or smelled) this stuff but it's the next thing from tar.

Ireland could instead have chosen to pull in gas from the North Sea and reduced the emissions of Moneypoint by not twelve but fifty to sixty per cent with modern CCGTs. Even older, more readily-available OCGTs would give thirty to forty per cent. This is ~250mmcf, i.e. probably a 24" spur line. Though this likely necessitates a few hundred km of loop for the ring main to the west, it's less than a year's work with a competent American crew.

Instead, she chose a paltry twelve per cent a few years earlier; when the other gas peaker capacity is installed, cooling infra and existing thermal plant talent base while paying to reconstitute all those on the other side of the island.

None of this is to say Ireland's work on decarbonizing her grid isn't real, but "coal-free" rather tends to obscure the present state of things; it is generally understood to make a strong, binary truth claim that isn't subject to "mostly" and implies one is no longer dependent on coal. It therefore demands consideration of electricity's fungibility in a grid.