For the second straight day, PJM Interconnection LLC issued a warning that rolling blackouts could be a strong possibility for E. Towanda, Pa., if one more generator or transmission facility failed.
PJM is the independent system operator for the electricity grid that serves much of Pennsylvania, New Jersey, Maryland, and Washington DC.
�We issue the warning when reserves are shrinking in a certain area and we can�t find more resources or reduce customer demand any further," says Cindy Taylor, customer relations manager for PJM.
"The next step is to impose a program of rolling blackouts.�
The warning for E. Towanda relates to the outage of certain transmission lines and is not caused by excess demand relative to the normal supply of power in that area, she says.
PJM has already tried to get any voluntary interruptible customers off the system in that area, Taylor says.
At about 5 PM Eastern Standard Time, rolling blackouts had not been required.
PJM issues a manual load dump warning when available primary reserve capacity is less than the largest operating generator or the loss of a transmission facility jeopardizes reliable operation after all other possible measures have been taken to increase reserves.
PJM currently administers almost 8% of the US's electric power, with a pooled generating capacity of over 58,000 Mw and a membership of more than 190.