SAN FRANCISCO, Jan 23 (Reuters) - California power company PG&E Corp, which expects to soon file for bankruptcy, said on Wednesday it would cost between $75 billion and $150 billion to fully comply with a judge's order to inspect its power grid and remove or trim trees that could fall into power lines and trigger wildfires.

PG&E in a filing in U.S. District Court in San Francisco said it could not on its own afford the work proposed in a Jan. 9 order by U.S. District Judge William Alsup, who is overseeing conditions of the company's probation following a 2010 gas pipeline explosion. To pay for the proposed work, PG&E said it would have to pass the bill to ratepayers who get their power from the company's nearly 100,000 miles of overhead lines in northern California. (Reporting by Jim Christie)