Staggs sat in the front seat and opened a MacBook Pro while the researchers looked up at the towering machine. Like the dozens of other turbines in the field, its white blades—each longer than a wing of a Boeing 747—turned hypnotically. Staggs typed into his laptop’s command line and soon saw a list of IP addresses representing every networked turbine in the field. A few minutes later he typed another command, and the hackers watched as the single turbine above them emitted a muted screech like the brakes of an aging 18-wheel truck, slowed, and came to a stop.

Source: Researchers Found They Could Hack Entire Wind Farms | WIRED

In a networked world, you need cyber security everywhere. Especially when physical access is so easy to get. The BeyondCorp model of not trusting the network is a really good starting place for systems like this.