PG&E Corp., parent of the bankrupt northern California utility, reported a $4.1 billion fourth-quarter loss Monday, acknowledging the company may be unable to recover soaring electricity costs it was unable to pass on to consumers last year. The San Francisco-based company recorded a before-tax charge of $6.9 billion, the difference between what it paid for wholesale electricity last year and what state regulators allowed the utility to charge its 4.5 million customers.