New provisional data from EirGrid shows that 42% of electricity in September came from renewable sources.

The majority of renewable electricity generated last month came from windfarms, which accounted for 34% of all electricity used in Ireland.

Total generation from wind energy amounted to 920 GWh (Gigawatt hours), compared with 776 GWh last September.

Some 97 GWh of electricity came from grid-scale solar last month, accounting for approximately 4% of electricity generated.

Elsewhere, 37% of electricity came from gas and 20% was imported.

Overall electricity system demand stood at 2715 GWh for September, up slightly from August.

EirGrid's carries out the complex task of balancing electricity supply and demand at all times from the National Control Centre.

Currently, the electricity grid can accommodate up to 75% of electricity from renewable sources at any one time. This is known as the system non-synchronous penetration (SNSP) limit.

Commenting on the data, Diarmaid Gillespie, Director of System Operations at EirGrid, said: "Wind energy represented the vast majority of renewable generation last month, which demonstrates the continued importance of this source of electricity for the power system.

As we head towards the winter months, we expect the fuel mix to change, with wind generation being more dominant, and a marked increase in demand for electricity, particularly after daylight saving ends and the clock change at the end of October."