sentences:  There was a significant consolidation among the remaining independent firms.According to the industry group NAESCO, revenues of ESCOs in the U.S. grew by 22% in 2006, reaching $3.6 billion.An energy service company (ESCO) is a company that provides comprehensive energy solutions to its customers, including auditing, redesigning and implementing changes to the ways the customer consumes energy, the main goal being improved efficiency.