Natural Resources Wales (NRW) has given the green light for a controversial 122.5m meteorological mast to be erected near Glaslyn Nature Reserve.
This brings Bute Energy one step closer to getting its planning application accepted by Powys County Council, which previously rejected the plans.
The proposal would see the mast erected for 36 months to gather data on whether weather conditions would be suitable for the Esgair Galed Energy Park to be placed there - a proposed project to erect up to 26 permanent wind turbines.
The mast and park would sit one kilometre away from the Pumlumon Site of Special Scientific Interest, 3.8km west of Staylittle.
The plans have attracted many objections, 99 against the original application.
A residents group has formed to protest the project, hosting a hike, photo competition and exhibition to highlight the natural beauty of the area.
However, NRW’s green light comes with many conditions including the use of bird deflectors along each outer guy wire, to be monitored for damage monthly.
It recommends that no external lighting be used outside of what is necessary for aviation safety, to avoid impact of nocturnal wildlife.
NRW calls for BSG Ecology’s report recommendations to be met, which has “identified habitats and species that have the potential to be impacted” by the mast.
BSG Ecology recommends defined working areas, work timings outside of bird breeding season, same-day backfilling of trenches and checking for reptiles before vegetation is removed.
Protect Glaslyn and Hafren Forest group aren’t pleased, highlighting a group of ospreys that successfully bred nearby this summer, adding that bird deflectors don’t “completely eliminate bird collisions, injuries and deaths”.
They state the Infrared LED lights for aviation would impact the rare Dark Sky status of the area, arguing that the mast shouldn’t be necessary at all with smaller wind-measuring systems available, used at nearby Dolydd Weather Station.
Bute Energy commented: "We are committed to not only protecting but enhancing habitats for local wildlife through the development of Esgair Galed Energy Park.
“We are conducting comprehensive surveys and ecological analysis as part of our planning application.
“We will report on this work in an Environmental Statement, which will be publicly available during our statutory consultation later this year.
“Our teams are out working in communities every day.
“We hope local groups reach out, give us their thoughts, and work with us to deliver a cleaner, greener future for Wales."