Nearly two thirds of UK renewable energy project applications submitted between 2018 and 2023 did not progress through the planning stage.
According to a report from Cornwall Insight, almost 63% of these projects were either abandoned, refused, withdrawn or expired.
Despite a rapid increase in the number of renewable energy applications, the approval rate remains low.
Only 20% of projects are currently at stages such as planning submitted, awaiting construction, or under construction.
No region in Great Britain has surpassed a 20% success rate for projects advancing through the planning process, the consultancy said.
One of the reasons cited for the low success rate is the rise in speculative applications.
Developers often submit multiple applications for various sites, anticipating that only a few will connect.
This has resulted in a growth of so-called “phantom projects,” which contributes to grid connection queues and complicates the progress of viable projects.
The findings from Cornwall Insight have raised concerns about the pace of renewable energy development in Britain.
Addressing speculative applications and streamlining the grid connections process are seen as crucial steps for ensuring a more efficient and successful path for renewable energy projects.
Lucy Dolton, Assets and Infrastructure Manager at Cornwall Insight said: “The total capacity of projects in the grid connection queue is currently well in excess of what is necessary for net zero generation capacity.
“However, considering the lengthy process for projects to progress through planning and gain grid connections, and the current volume of projects that are unsuccessful, the amount of this capacity that will ultimately connect could be much lower than the pipeline of projects suggests.”