 U.S. power utility DTE Energy Co is nearing a deal to acquire gas pipeline system M5 Midstream LLC for about 2.5 billion, expanding its business thats not tied to electricity provision, people familiar with the matter said on Thursday. Advanced energy efficiency measures have made the provision of electricity less lucrative for power companies such as DTE, which serves about 2.2 million customers in southeastern Michigan, including Detroit. In response, DTE has sought to expand its businesses that encompass natural gas pipelines and storage, because they provide steady cash flows even during energy price swings. 