Drones, low cost robots that are independently maneuverable, come in all shapes and sizes.
Here's an aquatic drone called a wave rider from Liquid Robotics. It has two parts. A surface craft that has a communications tower and a solar panel. It has a submerged portion that uses adjustable fins to capture wave power.
A couple of days ago, Liquid Robotics reported that their drone had reached Hawaii -- 3,200 nautical miles out of a 9,000 mile unmanned, un-refueled, and zero emissions trip to Japan.
On another note, here's an announcement of a project called the Low Orbit Server Stations (LOSS) by the team at Pirate Bay (the torrent search site that is constantly being raided by the global IP Cartel). The costs of drone technology and long range wireless tech (100 Mbps up to 50km) is so inexpensive now, that its possible to revive the idea of using blimps as Internet proxies. Essentially, these blimps can reach extremely high altitude 60k or so (above weather) and use solar power (flexible panels) to power itself (maneuver and for on board equipment). This allows these blimps to stay aloft for years.
The important insight here? Drones can travel great distances and operate for years without human intervention/support already. This capability will expand as they get smarter and more maneuverable.
Homework: Think about ways that land based drones (air/ground) can maintain operation in a built up area for a year or more while remaining mobile and independent.