The developers can appeal the decision.
Kildare County Council has refused plans for a major biomethane plant near Castledermot.
European firm CycleØ Group had sought permission for an anaerobic digestion facility at Ballyvass, but the Council has turned it down.
Ecological concerns had been highlighted during the process, including potential risks to rivers, wetlands, and protected species.
Local residents had voiced strong objections, while the company insisted it would meet all environmental requirements
The developers can appeal the decision to An Coimisiún Pleanála.

Water Outage In Place For Maynooth And Straffan Tomorrow
Kfm Obituary Notices
Nationwide Fuel Protest Continues Into Third Day
"I Don't Think Anybody Is Going To Really Listen To Us Until Somebody Dies On That Road": Criticism Of Moone-Timolin Cycleway Continues
International Wholesale Prices Are "Not Price Gouging", Says CCPC
Costs Of Home Heating Oil Up By 67.5 Per Cent Between February and March
91-Year-Old Lelia Doolan To Arrive In Monasterevin Today As Part Of Her Walk For Peace
Over €400,000 Awarded To Repair And Protect Three Kildare Heritage Structures