New figures from Gas Networks Ireland show that gas generated 46% of the country's electricity last year.
On an all-island basis, gas delivered 43% of electricity needs.
Gas Networks Ireland said that gas-fired generation was limited by greater than anticipated maintenance across a number of power plants and its share of the Irish electricity mix fell three percentages points when compared to 2020.
Wind's share of electricity generation also fell from 35% in 2020 to 29% in 2021, while coal generation climbed from 5% in 2020 to 11% in 2021.
At their peak, gas and wind powered up to 82% and 77% of Ireland's electricity needs respectively.
Gas Networks Ireland noted that the intermittent nature of wind saw it drop lower than 1% at times, while the contribution of gas did not drop below 10% during the year.
Two new Compressed Natural Gas (CNG) fuelling stations opened last year.
Demand for gas as an alternative to diesel in the commercial transport sector was up 78% year-on-year with further growth expected in this market in 2022, Gas Networks Ireland noted.
There were also increases in demand in sectors including retail (+18%), construction (+16%), laundry (+13%), leisure (+13%) and air travel (+10%), as Covid-19 restrictions eased during the year.
Brian Mullins, Gas Networks Ireland's Head of Regulatory Affairs, said that the responsiveness, flexibility and availability of gas makes it the ideal partner for renewables like wind.
"The amount of electricity generated by coal rose by 6% in 2021, compensating for maintenance at gas-fired power plants and less wind generation. As natural gas produces 40% less CO2 than coal, replacing coal-fired power plants with gas-fired power plants would deliver significant and immediate emissions reductions," Mr Mullins said.
"Having the reliability of 'always on' gas to be the constant back up supporting intermittent renewables, means that when the wind doesn’t blow and the sun doesn’t shine, our homes, businesses and vital services can depend on gas to help keep the lights on," he added.
