Wales needs to quadruple how much wind power it generates within a decade, according to a new report.
Industry body RenewableUK Cymru said "a giant leap" was needed if green energy goals were to be met.
It described the process of getting new projects built in Wales as "sluggish" and called for government action.
The Welsh government said its policies and planning systems were highly supportive of renewable energy.
Ministers in Cardiff Bay have set a target for all electricity demand in Wales to be met from renewable sources by 2035.
The report says the lion’s share of this would come from wind farms on land and out at sea.
It looks in detail at what it says are "a significant number of projects in the pipeline" - but face challenges in actually getting built.
There is the potential for generating 9GW of energy from these schemes over the next decade, but only if an “ambitious delivery plan” was put in place now, the experts said.
Wales currently has about 2GW-worth of wind power projects up and running.
The Welsh government took control over the consenting of large green energy schemes - under its developments of national significance (DNS) regime - in 2016.
Since then only one onshore wind farm at upper Ogmore has been given the green light - a decision which took almost two years - the report explained.
If ministers’ own electricity targets are to be met, "bold, collaborative action" between government and industry "to tackle significant barriers" were needed, it said.
Wind power the ‘backbone’ of net zero
RenewableUK Cymru director Jess Hooper said developers had been hampered for years by “an under-resourced, inconsistent planning system" as well as poor grid connectivity.
"As a result, Wales risks falling short of its power generation need by 2035," she said, adding that wind power was "the backbone of Wales' net zero ambitions".
The Welsh government said it was "highly supportive of well-designed renewable projects that meet our policy requirements and deliver in the interests of people in Wales".
"Our new targets and Future Energy Grids for Wales reports set out our expectations for new renewables and the new grid needed to deliver them, which will need action by UK government and Ofgem."
"We are working with UK government and networks to unblock this issue and make sure plans for a new grid deliver high value and low impact for people in Wales."