Texas’ power grid operator is asking residents to voluntarily cut back on electricity due to anticipated record demand on the system as a heat wave keeps parts of the state and southern U.S. in triple-digit temperatures. Much of Texas on Tuesday was under excessive heat warnings. The Electric Reliability Council of Texas' request is its first this year asking customers to curtail their energy use. In neighboring Oklahoma, meanwhile, more than 100,000 customers are eagerly awaiting the restoration of power and air conditioning following weekend storms that downed trees and snapped hundreds of utility poles. And in Louisiana, the Southwestern Electric Power Company says more than 93,000 of its customers remained without power as of Tuesday morning.