By Scott DiSavino

Aug 22 (Reuters) - Record breaking power demand will stress electric systems in the central U.S. this week as homes and businesses crank up their air conditioners to escape a brutal heat wave.

The Midcontinent Independent System Operator (MISO), which oversees the grid serving 45 million people in 15 states from Minnesota to Louisiana and Manitoba in Canada, said it has already notified all utilities to prepare every available resource to serve the projected load.

"We anticipate challenging operating conditions throughout the entire week, and we will need every available resource at some point," said Jessica Lucas, MISO's executive director – system operations.

AccuWeather forecast Thursday would be the hottest day so far this year in Indianapolis, a big city in MISO, with temperatures reaching a record-breaking 100 degrees Fahrenheit (37.8 Celsius).

That would top the current record of 98 F for that day in 1936 and compares with a normal high of 84 F for this time of year.

"We have issued several alerts and advisories based on the weather forecast. More emergency procedures may be required to keep the power flowing. That’s typical for a weather event like this," Lucas said.

Those additional emergency procedures could include calls for energy conservation and - in an unexpected worst-case situation - controlled, rotating outages to avoid uncontrolled blackouts.

MISO projected demand would reach 127,265 megawatts (MW) on Wednesday and 130,107 MW on Thursday, topping the current record of 127,100 MW in July 2011.

To meet that load, MISO expects to have around 136,400 MW of resources available on Wednesday, including about 131,600 MW of generation in MISO and 4,800 MW of imports from other regions, and almost 133,400 MW on Thursday, including about 128,800 MW of MISO generation and 4,600 MW of imports.

WIND POWER IS KEY

There are around 30,000 MW of wind power capacity in MISO. The grid operator forecast wind would provide around 11,100 MW at the peak hour on Wednesday and 7,400 MW on Thursday.

The North American Electric Reliability Corp (NERC), which oversees power reliability in the U.S., Canada and parts of Mexico, said wind power would be key to determining whether MISO will have enough supplies to maintain reliability this summer.

"MISO can face challenges in meeting above-normal peak demand if wind generator energy output is lower than expected," NERC said in its Summer Reliability Assessment in May.

In 2022, about 34% of the power generated in MISO came from coal-fired plants, with most of the rest coming from gas (33%), wind (16%) and nuclear (14%), federal energy data showed. (Reporting by Scott DiSavino, Editing by Nick Zieminski)