Hellisheidi (Hellisheidarvirkjun)Geothermal Power Station, South Iceland. The power station is located in the Hengill volcano area. Hengill is a volcano made from palagonite tuff and its highest point is around 800 meters above sea level. Hengill geothermal area is located in the middle of the western volcanic zone, on the plate boundary between North America and European plates. The area is one of the most powerful geothermal areas in the world with several thousand of hot springs at the surface and a giant magma chamber lying underground. Hengill volcano is still active, although its last eruption occurred about 2 000 years ago.