(Adds GM, Fiat Chrysler statements)
By David Shepardson
WASHINGTON, Jan 31 (Reuters) - General Motors Co and Fiat Chrysler Automobiles NV said on Thursday they plan to resume normal operations after they were forced to cancel shifts at plants in Michigan over concerns about the state's natural gas supply.
The cancellations came after CMS Energy Corp made an emergency appeal to users late on Wednesday to conserve natural gas following a fire at a compressor station and extremely cold weather.
Fiat Chrysler said it would resume normal operations on Friday after it canceled two shifts at its Warren Truck and Sterling Heights Assembly plants on Thursday.
GM said late Wednesday it was suspending operations at 13 Michigan plants and its Warren Tech Center due to the CMS request. It resumed limited operations at five engine, transmission and stamping plants on Thursday afternoon.
GM said late on Thursday it would resume operations on Friday at all manufacturing facilities and some critical labs, testing and other limited locations.
GM said employees at three locations including the Tech Center will work from Friday and added it expects normal operations to resume in full over the weekend.
Ford Motor Co said it had also taken steps to reduce energy use at its four Michigan plants supplied by CMS.
CMS, the parent company of Consumers Energy, took the unusual step of issuing an urgent appeal to 1.8 million Michigan customers on Wednesday asking them to lower their thermostats to ease the burden on the system due to the fire and record cold weather.
The company said Thursday that consumers could resume normal usage at 12:01 a.m. Friday.
CMS Chief Executive Patricia Poppe said earlier on Thursday about 79 large users in Michigan including major automakers, other manufacturers and two universities had curtailed their natural gas usage. Along with individual consumers, usage had fallen by about 10 percent over anticipated demand, she said at a news conference on Thursday.
Michigan State University said it cut hot water to some buildings and reduced temperatures in some buildings.
The White House National Security Council weighed in on Twitter on Thursday urging people in Michigan to listen to state and local authorities "tonight and tomorrow re natural gas use in the coming days." (Reporting by David Shepardson Editing by Phil Berlowitz and Richard Chang)