Sorry that I don't have pictures.
Imagine I have a steel circle, like a hula hoop. On opposite sides of that circle I attach two springs, then stretch them. They meet in center where I hook them together. The springs keep pulling on each other, and the circle, but they are in equilibrium and the system stays static. Unless it rusts to pieces, it will stay that way for millennia. No energy is being used here.
Now let's replace one spring with a not very elastic string. One end is still attached to the circle. On the other end I add an electromagnet. The spring which remains also gets modified slightly - instead of a hook, I add a little metallic plate which the electromagnet can attract.
Now, when I turn on electricity, the magnet attracts the plate and keeps the spring stretched, just like in the first case. But in this case, I need to keep spending electrical energy in order to keep the spring taut. Work is being done, heat is being generated. The system is still static, unmoving - but as soon as the battery runs out, the magnet will release the spring.
Why is this? Why is there work being done even if nothing is moving, just like in the first case?