Fixing the world's biggest blackout

About 10 percent of the world's population lost power recently as a blackout swept across northern India. As many as 700 million people, or twice the population of the U.S., were affected. Fortunately there have been no reports of deaths connected to the blackout, but the loss of power did result in traffic snarls, stranded train passengers and a group of trapped coal miners.

So what can the world's biggest democracy do to help stave off such wide-sweeping outages in the future? To find out, I spoke with Jason Black, a research leader in grid systems with Battelle's Energy, Environment and Material Sciences Global Business.

Black characterized India's power grid as reasonably good on the transmission side, but a bit dodgy on the distribution side. Furthermore, the country has struggled with power shortages as its current generation mix often can't meet the demands of the population.

"In many sections of the country, they use rolling blackouts regularly," Black said. "But I don't think it's as simple as an excessive load. There are protection schemes in place to deal with that."

In recent years, India has worked to encourage investment in new power generation of just about every type, including distributed renewable generation like solar energy, of which India now has about 1 GW.

"Traditionally they have used coal, and they have some hydro as well. They have made some legislation that was meant to increase their renewable capacity — just as a way to try to correct some of their power shortages," he said.

In addition to bringing more generation online, India's grid operators have attempted to interconnect their grid more thoroughly — an approach not without its dangers.

"[Interconnection is] good from one perspective, because the redundancies can address an interruption in one area. But from another perspective, it can increase the risk of cascading power outages, which it appears this one is."

Though its transmission grid is reasonably well developed, India's rapid development and population growth have left it with a distribution system that often falls short of the task of delivering power to those that need it.

"They have had some ongoing problems with electricity theft, which has become a local political problem and leads to losses, making the pull on the system unpredictable. Cleaning up the distribution system would help them a lot," he said.

For one thing, India's grid could implement underfrequency load shedding as is done in the U.S.

"In the U.S., we operate our system at 60 Hertz. This keeps the power flowing in sync, so generators don't trip offline. Imbalances in demand and supply are what cause these kinds of outages — when the generators can't handle the imbalances. That's one way to get these cascading power outages," he said.

To prevent further outages during the restoration process, India's grid operators need to be careful how they manage the grid in the coming days.

"If you're a steam plant and the system has tripped off to protect itself, your steam cools off. It can take many hours to return to service. Depending on how many of their generators have black start capability, that process can take a while," he said.

As generators start spinning again, grid operators have important choices to make.

"There's a trade off. Do I bring on all my generators, or do I bring on a certain subset of customers that I can get to faster?" he said. "If there isn't enough slack in the system when you start up these plants, it can bring the system offline again."

Furthermore, there might be physical damage to the grid that needs fixing — delaying restoration even more.

"There could be parts of the grid that broke... Some transformers that exploded or some circuit breakers that opened. They have to deal with those things before bringing the grid back online," he said.

Black said this blackout is likely one of the worst in history, in terms of the number of people affected. While Indian officials are still investigating the causes, it bears all the telltale signs of a cascading power outage, like the Northeast blackout of 2003, which began in Ohio, ran through New York and into Canada. But even in a blackout so widespread in North America, only 55 million people were affected. It's almost unthinkable to most of us to imagine 700 million people without power.

But that's pretty much how it always goes with power outages, as people in the utility industry know. People don't think about it at all until the lights go out. Then the next day (hopefully) when they come back on, the finger-wagging starts.