Ten years ago, a giant power blackout hit the northeast United States and Canada. At the time, it was the second most widespread electricity outage in history. But now researchers have found that an even bigger event is more likely than many would like to think. A recent study revealed that the power grids that span continents are even more vulnerable to catastrophic failure than previously believed.
Many kinds of networks can be linked together to form complex systems like the interlinked network of websites we call the World Wide Web. Recent studies regarding these kinds of systems, which are called interdependent, found that once a certain fraction of the nodes comprising them fail — say, 20 or 30 percent — the interdependent network would not just gradually fail, but abruptly and totally collapse.
"When you have a system where some networks depend on others, it can collapse by cascading failure. Since one network depends on others, once nodes in one network fail, you have failure in another, and then another, and so on," says Shlomo Havlin, a physicist at Bar Ilan University in Ramat Gan, Israel.
Imagine these formerly dumb systems gone smart: a roof that announces when it’s about to spring a leak; a garden that monitors moisture on its own and applies just the right amount of water when it’s needed; and a bridge that automatically puts in a work order at the first sign of a hairline crack in a support structure.
These are just a few of the innovations promised by the growth of the industrial internet, a communications network in which objects and machines generate data about themselves and communicate it with each other to make better decisions about how they operate. This advance promises major efficiency gains—think of a jet engine monitoring and injecting fuel precisely when it’s needed. It will also mean cost reductions through repair and maintenance that head off problems before they become major, among other advantages. But for this more-automatic world to take root, objects of all sorts need to be embedded with simple instruments—moisture detectors, accelerometers, and identification chips—that can sense and communicate their state to the broader world.
One of the major constraints of this potentially disruptive technology taking off is the power requirement of these sensors, which must be fed either by wires or batteries. But how does one install a wireless moisture detector into a roof and then periodically go in to change the batteries? How would a farmer gather up thousands of cheap sensors embedded in the soil that tell an irrigation system when to work after they’ve been spread over the land?
“Sensors have needed batteries up until now, which makes deploying them difficult because you have to maintain those batteries,” University of Washington computer science and engineering professor Shyam Gollakota tells Txchnologist. “We asked, ‘Can you generate power without batteries?’”