PJM, which manages the grid serving nearly a fifth of Americans from the Midwest to the mid-Atlantic, also asked dual-fuel generators to procure and burn gas supplies to preserve oil for later in the week, according to staff. Soaring gas prices have made it more economic to burn oil on the East Coast, and the fuel was producing about 5.8 gigawatts Sunday evening, or 4.6% of the generation mix, PJM data show.