Solar irradiation in Ireland can be very different from place to place. Clouds play the major role in here. I live on the coast and can see that very often clouds are forming few miles in land when it's still sunny on the coast. Same thing can happen with hills around. If you consider your area sunny you should definitely consider solar system.
Maps of solar radiation are not very precise but most of them show higher radiation farther south and in coastal areas.
Estimation of annual production can be very simple. For south faced, tilted at 30 degrees good quality system you can expect 1MWh of energy from 1kW. That could be more in more sunny areas and less.
I am using PV SOL Premium software to design system and estimate energy production for clients (takes shadow, inverter efficiency, loses, and many many other factors in to account ) but for your basic needs this online calculator should do.
If you want to read more check SEAI PV guide