Smart grid may crush power companies at unexpected moments: MIT study

The smart grid could go a long way in conserving energy and smoothing out load demand for the nation's utilities. Researchers at MIT however, say there may be a law of unintended consequences at work with smart grid. If too many people set appliances to turn on, or devices to recharge, when the price of electricity crosses the same threshold, it could cause a huge spike in demand -- and potentially overload the power grid, they surmise.

Kind of like an e-commerce site going down at a half-price sale, without having additional servers online to carry the extra load. Or a store getting crushed on Black Friday.

In a paper presented at a recent IEEE conference, the researchers, Mardavij Roozbehani, Sanjoy Mitter and
Munther Dahleh, warn about the issues utilities could face as the smart grid expands.

Electricity consumers will act just as rationally as they would for any other type of good or service: that is, they’ll try to get as much convenience for as little money as possible. Smart grid devices provide real-time information on when electricity is retailing for less.

Roozbehani says he and his team determined that if that a there were a sudden shift of millions of devices to a low-demand period, this would increase the load and require re-firing up generators, which will tax the grid in unanticipated ways.

Roozbehanihe cautions:

“For the system to work, supply and demand must match almost perfectly at each instant of time. The generators have what are called 'ramp constraints': They cannot ramp up their production arbitrarily fast, and they cannot ramp it down arbitrarily fast. If these oscillations become very wild, they’ll have a hard time keeping track of the demand. And that’s bad for everyone.”

However, it wouldn't make sense to back off on flexible pricing, either, they say. If pricing isn't flexible enough to shape demand, there’s no point in installing smart meters, which are intended to give customers real-time information about fluctuations in the price of electricity, and thus encourage them to defer some energy-intensive tasks until supply is high or demand is low.

Smoothing out load profiles -- so that as much electricity consumption as possible is shifted away from peak periods (such as 9 to 5 on summer days) to off-peak periods is a challenge utilities have been wrestling with for decades. Are the researchers suggesting that they ought to be careful for what they wish for?

Roozbehani suggests that there be more communications between utilities and consumers. One idea is to ask customers, through questionnaires, how they would respond to different prices at different times. Then, utilities then could more effectively tune the prices that they pass to consumers much more precisely, to maximize responsiveness to fluctuations in the market while minimizing the risk of instability.

Roozbehani admits, however, that collecting that information would be difficult.

The researchers didn't address this, but perhaps this is a ripe area for even greater analytics. The smart grid could respond to in-depth data pertaining to consumers' price sensitivity with various devices (air conditioning versus  cell-phone charging).

This post was originally published on Smartplanet.com