Baltimore-based Constellation’s plans to acquire a Houston, Texas,-based natural gas  producer in a $26.6 billion deal will create one of the nation’s biggest energy firms at a time

Constellation Energy agreed to buy Calpine for $16.4 billion, combining two of the country’s largest electricity generators at a time when their product is in high demand from tech companies.Including the assumption of debt,

Constellation Energy is nearing a roughly $30 billion deal to acquire power producer Calpine, people familiar with the matter said on Wednesday, a move that would significantly expand Constellation's generation assets at a time of rising U.