HOUSTON — A high-stakes fight is emerging as the AI boom accelerates: Should data centers plug into the grid, or operate as energy "islands"?Why it matters: The debate is shaping power flows and multibillion-dollar investments, as data centers rival entire cities in their electricity demand.Driving the news: Chevron said this week it's working on a deal to build a natural gas plant dedicated to a Microsoft data center in Texas — one of many signs that on-site power is gaining traction.Roughly 30...