The facility’s key feature is the rapid off-and-on capabilities of the computers. When use dips, they can quickly ramp up activity. When it peaks, they can ramp down at a moment’s notice.
That kind of flexibility, Ameren says, can be increasingly valuable on the modern electric grid, where both power supply and demand are now prone to greater swings. Solar arrays and wind turbines produce more in sunny and windy conditions. And demand is becoming more variable, too. For example, when the sun sets, homes with rooftop solar installations can suddenly need power from the grid.
The company’s data center project cost about $1 million to install, and has been running since April. Ameren said it was put at Sioux because of available space, and that it is not hooked exclusively to the coal-fired plant as a source of power.
But even though it draws energy from the overall electric grid, the region is awash in power from coal, which accounts for about two-thirds of Ameren’s generation. And Missouri, overall, burns more coal than any state except Texas, according to the latest government data.
The data center can use a half of a megawatt of electricity, if running full tilt. By comparison, the 54-year-old Sioux plant — the third-largest of Ameren’s four coal plants — has capacity to produce 972 megawatts.