Thursday, August 2, 2012
More than 600 million Indians were affected by this week's grid outage (see "How Power Outages in India May One Day Be Avoided"). But it would be a mistake to think that India is uniquely vulnerable to large-scale grid failures. The growing complexity and reliance on the electric grid in both developed and fast-growing countries is making stability tougher to achieve.
India, in particular, operates its grid with one very large handicap: insufficient power. With demand for electricity regularly outstripping supply, grid operators ration out power by periodically cutting service in some areas. The situation has been made worse this year by a drier monsoon season, which has prompted northern farmers to run pumps and draw more power than usual.
Few, if any, countries suffer the same gaping mismatch between power need and availability. But India's disaster illustrates the perils of relying on manual control of the grid as these systems get overtaxed and more complicated. To make grids around the world more reliable, operators need to incorporate more advanced control technology, which can help grids recover gracefully from disruptions.
"Any complex interactive system is prone to break up. You can minimize the risk, but you can never prevent a failure," says Arshad Mansoor, senior vice president at the Electric Power Research Institute. "Saying the reason for India's gridwide collapse was that they had more load than generation is too simplistic."
It will take months to pinpoint the root cause of failure in India, but Mansoor suspects it is something fairly mundane, such as a failed relay or a grid operator making a mistake. Grids in other countries are prone to the same disruptions, triggered by events such as falling trees and generator breakdowns. And as more solar and wind power joins the generating fleet, it becomes even more challenging to maintain grid stability, since these sources supply power intermittently. Water shortages, too, could increasingly hamper power generation.
The primary function of grid operators is to anticipate load and to maintain a steady balance between power supply and demand. The grid signal operates at a set frequency—60 hertz in the U.S. and 50 hertz in India—and when supply and demand fall out of sync, the frequency will either dip or rise. In the U.S., grid operators have "hot" generators on standby to ramp up power in order to keep a close-to-steady frequency, but that's not the case when generators are routinely maxed out.
"In a developing world country, it's tough to keep 10 percent of the generation capacity on contingency when you may use it once in a lifetime," Mansoor says. "You're not using the generator, but you still pay for it. That's tough to do."
More technologies to keep that frequency steady are emerging. Sensors called phasor measurement units are designed for real-time measurement of grid frequency, and can flag potential problems. Grid operators in the United States are increasingly using automation to manage demand-response programs that lower consumption at big power users at peak times. These types of technologies as well as microgrids (see "Microgrids Keeps the Power Local, Cheap, and Reliable") stand to make electricity grids more reliable as more renewable resources come online and weather-related events, such as heat waves, strain generating resources.
Still, there's little doubt that the causes of India's blackouts have more to do with politics than technology and engineering. Reports from India suggest that northern states have been consistently overdrawing power in response to drier weather over the past few weeks, but federal regulators did not discipline them out of fear of losing political support for the ruling party in Parliament.
The price of electricity is also controlled, which has led to an underinvestment in the grid. "This is an endemic problem, so there has not been nearly adequate investment in transmission and distribution," says David Dapice, an economist at the Harvard Kennedy School's Ash Center for Democratic Governance and Innovation. Coal, which supplies the majority of energy in India, is also controlled by a government-owned company, and there is a debate over how and whether to expand mining.
The conflict between water and power, seen in India's blackout, is poised to become more acute as weather patterns change and fast-growing economies consume more water. A 2010 report from the World Resources Institute, a Washington-based environmental think tank, says economic and population growth are stressing freshwater suppliers in India, Malaysia, the Philippines, Thailand, and Vietnam. With the rapid expansion of thermal and hydroelectric plants and longer dry periods, many countries in Asia and elsewhere will face water-related risks in power generation, the report said.
The scale of India's suffering from power outages this week is hard to fathom. But it's easy to see how the current regulations and a lack of investment in infrastructure are hampering its progress. That's a lesson for us all.
With additional reporting from Narayanan Suresh in Bangalore, India