For most homeowners, no — there's a generous tax-free allowance and you'll rarely exceed it. Income from selling your surplus solar back to the grid (the Clean Export Guarantee, CEG) is exempt from income tax, USC and PRSI up to €400 per year per qualifying individual, and that exemption now runs to 31 December 2028 (it was raised from the earlier €200 figure and extended in the Finance Act). Where two people are named on the electricity account, each can claim the €400 — so a jointly-held bill is effectively €800 of export income tax-free.
In practice that covers the vast majority of domestic systems: a typical home exports a few hundred euro of surplus a year, comfortably inside the allowance. You don't need to do anything to claim it, and your supplier doesn't withhold any tax — the export payment lands in full. It's only if your export earnings exceed the exemption (a big array on a low-consumption home that dumps a lot to the grid) that the excess above €400 (or €800 joint) becomes taxable, declared yourself through Revenue's MyAccount and taxed at your marginal rate plus USC/PRSI.
So the people most likely to bump into it are heavy exporters — large systems, low daytime usage, no battery to soak up the surplus. If that's you, it's another argument for sizing the system to your own consumption rather than oversizing purely to export, since beyond the allowance the export income is taxed and the CEG rate is modest to begin with. For everyone else, treat the export earnings as tax-free and don't worry about it.