A low pitch humming noise and a series of bright lights noted at ground level near an electrical power plant

Details somewhat sketchy over the years but the experience certainly not something I will ever forget. Location was near the Hutsonville Power Plant. I was out in a car with my boyfriend on a dark country road. I hate to admit it but yes,parking. We heard a low pitch humming noise and looked out the back window of the car to locate the noise and saw a series of very bright lights. I believe they were just white but that detail is not clear to me now. The craft which was disk shaped was either on the ground or hovering very close to it. We both watched the craft rise up off the ground 20 feet or so and lower. It then rose up vertically above the trees and then took off in a diagonal path across the sky with spectacular speed. Needless to say we were scared to death and as he drove to get out of there I followed the bright light in the sky scared to death it would follow us....it did not. When we made it back in town we met up with a group of friends and told of our sighting. We were  believed and told that others had seen bright lights around the power plant before. Scary experience and I totally believe!
Date is approximate.  PD