A new study from Energy Storage Ireland and TNEI finds long-duration storage could cut electricity grid fossil fuel generation by more than 2TWh a year.
The report models a future all-island system with 9GW of onshore wind, 8GW of solar and 5GW of offshore wind to assess how storage can strengthen the grid and displace fossil fuels.
ESI said eight-hour storage portfolios would reduce fossil generation by up to 1TWh annually while 100-hour duration assets deployed across the grid could double that impact.
Launching the report, Bobby Smith (pictured), director of ESI, said fossil fuel output remains at about 7.4TWh in 2035 under a high-renewables scenario.
He added that the introduction of energy storage at scale significantly lowers that reliance.
“This represents a nearly 30% reduction in fossil fuel use within the power system and demonstrates the transformative role long-duration storage can play in a deeply decarbonised grid,” said Smith.
The study also found renewable dispatch down reached about 1.72TWh in 2025 and could rise to 11TWh in a modelled 2035 system without intervention.
ESI added that long-duration storage would substantially reduce this waste and lower import costs and consumer bills.
Smith stated that the findings underline the importance of long-duration technologies in delivering Ireland’s climate ambitions.