Biggest U.S. power grid PJM hits monthly record due to cold snap Wed Nov 19, 2014 3:28pm EST (Reuters) - PJM Interconnection, the operator of the biggest power grid in the United States, said on Wednesday that demand for power hit a new record for the month of November due to the cold weather. Peak demand on Tuesday reached 121,987 megawatts (MW), topping the 114,699 MW reached last November. Last winter, several power plants in PJM and elsewhere in the U.S. Northeast were not able to operate on the coldest days in part because there was not enough natural gas to fuel both the power units and heat homes and businesses due to pipeline constraints. PJM, which operates the grid in 13 states from New Jersey to Illinois, said it has been taking steps to prepare for the winter season, including more testing of generating equipment and improving coordination with the gas pipeline industry. Reporting by Scott DiSavino; Editing by Chris Reese