Currently, wind and solar power seem to me to be the only real prospects for the power generation of the future. And while they seem to allow for a small impact on the environment, like the hydroelectric plants of the generation before them, there are unseen side effects to animal populations and ecosystems. Especially when implemented on industrial scales (wind and solar farms), these renewable and clean sources of energy can have detrimental impacts on the wildlife around them mainly due to the large technological monuments we use to “harvest” the energy. For wind power specifically, one of the larger concerns is the large toll that wind turbines inflict upon bat populations. Bats seem to be attracted to wind turbines for reasons unknown to scientists, and the attraction seems to be most acute with migratory bats which roost in trees.
In an effort to reduce bat fatalities a la wind turbine, a study was conducted at a wind farm site in Indiana in 2012. The findings there showed that turning off or reducing power generation at night reduced bat fatalities by nearly a third. On calm nights with low winds, when bats tend to be more active and windmills generally less productive, turning off the turbines is considered both economically feasible and of no significant impact to overall production.
And while this effort is to be applauded, the next solution for both wind and solar power should be the removal of industrial scale farms. Smaller, individual turbines and panels based in situ for home, office, and complex consumption is going to be the answer for limiting the ecological impact of these technologies in the long term in my humble and modest opinion.
For a further discussion of wind power and bats check out this article from the National Geographic Society here.