Many of the power plants being built for AI do not show up in official data. Official energy statistics only track plants tied to the grid, so much of what AI campuses build on site goes uncounted. Plants like these are expected to power more than half of the new U.S. data center capacity coming online in 2028. Builders are bringing their own power because the grid cannot connect new load fast enough. One off-grid campus in Texas alone plans more than 500 gas engines. Engine makers’ order books show the buildout more clearly than the official data does. INNIO booked $6.1 billion of orders in the first nine months of 2026, nearly double a year earlier. Caterpillar’s backlog of large engines has more than tripled since early 2024, and Wärtsilä’s energy orders have more than doubled since early 2025. These plants are likely to stay after the grid arrives. Some providers now build and run them for data centers under contracts that last up to 18 years, including extensions. A growing share of AI’s power now comes from plants beside the grid, many of them outside the official numbers.