Ireland is set to miss EU 2020 targets for renewable energy use, according to the Sustainable Energy Authority (SEAI).
The authority's latest report shows an estimated 13% of the country's energy will come from renewable sources by next year.
However, that's short of the European target of 16%.
A breakdown of the figures shows the transport sector is likely to meet its EU target, "but only when multipliers for sustainable biofuels are included".
Both electricity and heat targets are expected to be missed, however, with the larger gap for renewable energy use for heat.
The SEAI says Ireland is 26th out of the EU-28 for progress towards the overall 2020 renewable energy target.
Despite the likely failure to meet EU targets, there has been a "significant increase" in renewable energy share here over the past few years.
The 13% estimate for 2020 would represent a jump from the 5% recorded in 2005.
The authority suggests the associated reduction in carbon dioxide emissions will be equivalent to taking 1.6 million cars off Irish roads.
Jim Gannon, CEO of SEAI, said: "As a country we must continue to make progress on energy efficiency across all sectors and rapidly increase the adoption of renewables across heating, electricity and transport, if we are serious about reducing Ireland’s carbon emissions."
Climate Action and Environment Minister Richard Bruton acknowledged that a "significant step" is required to decarbonise Ireland's energy supply.
He reiterated his pledge that an 'all of government' climate plan will be published shortly.