"The red spots are small volcanoes made up of felsic rocks. We know from data returned by the DIVINER thermal imaging spectrometer on Lunar Reconnaissance Orbiter that these landforms are rich in silica. From the Lunar Prospector gamma-ray data, we have determined that they are also enriched in the element thorium, a key indicator of chemically evolved rock types."
It wouldn't take much thorium to make a lot of energy. Plus, it is near the North Pole, which makes it near a source of water.