The plot as best as I can remember it:
Two scientists are notified that a warehouse has exploded and they are sent to investigate. Upon arriving they discover that all the steel girders are pointing to the inside of the warehouse. The warehouse did not explode, it imploded!
Using the girders to point to where the implosion occurred, they find something. Back at the lab, they are trying to analyze the thing and it wants to eat energy again. Things fly around the room and it causes destruction. From this they determine it feeds every 48 hours (could be more or less) and grows more hungry after every feeding. At some point it will be so hungry that it will devour the earth.
One scientist reasons that they cannot kill it when it it dormant so they have to try and kill it when it is feeding. Forcing it to eat too much energy is the only possible way to kill it. They use a hydroelectric dam to do this.
It was possibly a Canadian show.