(Reuters) - Pennsylvania Governor Josh Shapiro on Tuesday said he has reached an agreement with grid operator PJM Interconnection to settle his recent complaint about its power market rules and save consumers over $21 billion in energy costs over two years.

The agreement would save consumers from excessive price hikes  in all 13 states that PJM distributes electricity to, Shapiro said in the release.

In December,  Shapiro  filed a complaint  with the Federal Energy Regulatory Commission (FERC) against PJM Interconnection, criticizing flaws in PJM's capacity auction design that threatened to impose significant new price increases.

According to the agreement, PJM's upcoming capacity auction price cap was lowered from over $500 per megawatt-day to $325 per megawatt-day, averting billions in unnecessary energy costs for 65 million people in the region.