Odds of Getting In
Geothermal energy is a burgeoning field that's only getting bigger. Ride that wave (a heat wave, of course) as far as it'll take you. While there are no specific stats on the prospects of a recent graduate with a specialized background in geothermal engineering, there are statistics available for closely related fields.
Environmental engineering will see 15% job growth in the next decade, meaning an additional 8,000 jobs (source). Electrical engineers, by contrast, face a 4% job "growth," which is much slower than average (source).
A master's degree in geothermal will help set you apart from the rest of the pack. It'll also help to have a particular specialty, such as designing the electronic system that organizes the plant. Your odds of hanging on are best bolstered by focusing on the environmental aspects of geothermal power: assess how it impacts wildlife and plant life and crush your competitors—wind and solar energy—in the race to replace fossil fuels.