The United States has voiced concerns about an initiative championed by Lopez Obrador which aims to strengthen state control of the power market at the expense of private companies.
Lopez Obrador said no topic will be off the table, and highlighted possible talks on his proposed power industry changes during the visit in which Granholm will meet him as well as the Mexican foreign and energy ministers.
The leftist nationalist leader said he would be happy "to inform about the reforms if necessary, or if she wants to know my opinion, I will be happy to give it to her."
The initiative due to be debated in Mexico's Congress in coming weeks has alarmed private investors, and the U.S. ambassador has said Washington had "serious concerns" about it.
Lopez Obrador argues that previous Mexican governments rigged the energy sector in favor of private capital to the detriment of consumers and Mexico's state-run energy companies.
The Mexican president said he would also thank Granholm for the United States approving the takeover of Royal Dutch Shell's Texas-based Deer Park refinery by Mexican state oil company (Petroleos Mexicanos) Pemex.
(Writing by Drazen Jorgic; Editing by Chizu Nomiyama)