Calpine Geothermal Visitor Center is just w. of SR 29 at 15500 Central Park Rd. Calpine is a leader in the production of renewable geothermal energy, which naturally occurs underground and is harnessed to spin turbine-generators to make electricity. Interactive exhibits provide information about geothermal energy at The Geysers. Guided bus tours to a nearby power plant are offered; advance reservations are required. Phone for details, including the tour schedule, or sign up online.