Even though Lafayette has its own utility system, most of the electricity its customers consume is generated elsewhere, making Lafayette Utilities System reliant on the electrical power grid and subject to rolling blackouts during emergencies.

Greg Labbé, LUS electric operations manager, said the city-owned utility system cut off electricity Tuesday to about 17,500 of its 70,000 business and residential customers for up to 30 minutes at a time while temperatures were near or below freezing. That's about 25% of its customers.

He did not rule out the need for further rolling blackouts this week as another wave of freezing temperatures and potential wintry precipitation is expected to hit the state.

"We won’t be fully out of the woods until Saturday. It depends on what happens in North Louisiana," Labbé said. "There's a lot of generation and transmission that way."

LUS, like other utility systems, Labbé said, was ordered Tuesday to reduce its burden on the electrical grid to prevent an overload that could have caused a massive, long-lasting power outage.

The grid is a system of power generation and transmission lines, in this case operated by Midcontinent Independent System Operator (MISO), which LUS joined in December 2013.

City leaders pride themselves on the fact that Lafayette owns its utility system. But most of the electricity the city provides its customers is no longer generated in Lafayette.

LUS, the Louisiana Energy and Power Authority and Cleco own a coal-powered electrical generating plant called Rodemacher 2 in central Louisiana, which provides LUS with around 50% of its electricity.

LUS also owns two quick-start combustion turbines that generate electricity. Both are located in the city but aren't operated on a daily basis. They were purchased primarily to produce a boost of electricity when demand is high, like mid-summer.

It was MISO that ordered LUS and other area electricity providers to institute rolling blackouts Tuesday based on a percentage of their load on the power grid. LUS looked at blocks of circuits to temporarily cut off until they reached the required megawatts the utility system had to shed, Labbé said.

LUS instituted two rolling blackouts, each about 30 minutes long, one Tuesday morning affecting about 11,000 customers and another Tuesday evening affecting about 6,500 customers. They were spread out across the city, Labbé said.

No customers lost power twice from the rolling blackouts. Neighborhoods connected to the same circuit as hospitals were spared.

Alison Alleman, LUS customer and support services manager, said they could not provide details at this time about which neighborhoods had their electricity turned off during the rolling blackouts.

"We're still in emergency mode," she said. "A lot of our teams are still working through the event."

Alex Antonowitsch, LUS public information specialist, asked customers on Wednesday to continue to conserve energy by setting the thermostat at 68 or lower, especially when you leave your house for work. Try not to use major appliances like dishwashers and washing machines and unplug devices that aren't in use, such as computers and other electronics.

Email Claire Taylor at ctaylor@theadvocate.com.