Surveys at the Ivanpah solar site in the Mojave predicted at most 32 desert tortoises, and crews then unearthed close to 1,000, halted construction for three months and spent 56 million dollars reloca

Key Points:

• Initial surveys at the Ivanpah Valley solar project estimated around 32 desert tortoises in the 3,500-acre area, with permits allowing relocation of up to 38 adults and a maximum of three accidental deaths per year.
• Construction revealed a much larger tortoise population than expected, with estimates rising to 162 adults and 608 juveniles on-site, causing a three-month halt in excavation work in 2012 due to regulatory limits.
• BrightSource spent $56 million on extensive tortoise rescue efforts, including hiring biologists, building a nursery, post-move monitoring, and installing tortoise-proof fencing, making these tortoises among the most expensive wild animals ever relocated.
• The undercount was largely due to tortoises being underground during drought surveys; wetter conditions during construction brought them to the surface, highlighting the need for multi-season surveys and larger relocation budgets in future projects.
• Ivanpah serves as a key example of the ecological challenges in renewable energy development, illustrating both the environmental costs and the effectiveness of mitigation measures when endangered species are encountered.