A study published in the journal BioScience found that increasing the wind speed at which turbines begin spinning (called “cut-in” speed) could significantly reduce bat deaths at wind farms.
Raising the cut-in speed from 3 m/s to 4.5 m/s on average reduced bat deaths by 40% according to the global study. Higher cut-in speeds could provide even more reduction.
A trial in Victoria, Australia lifted the cut-in speed to 4.5 m/s and found it reduced bat deaths by 54% while only reducing energy output by 0.16% and revenue by 0.09% for the wind farm operator.
Curtailment has been recommended in draft wind farm guidelines in Australia but is not widely used yet. More research is being conducted in Victoria to reduce bird and bat collisions.
Experts say curtailment works because bats are more active at lower wind speeds when turbines aren’t producing as much energy. Centralizing bat collision data in Australia is needed to better understand and address the problem.
The clean energy industry group says risks can be managed but curtailment may not always be appropriate, while more research is still needed. Conservation groups support renewable energy but want plans to minimize bat deaths.
Source: the Guardian
