In practice, you would need multiple cables, some for going up and some for going down. And then there is the power/energy factor. Lifting a cargo up would tak

In practice, you would need multiple cables, some for going up and some for going down. And then there is the power/energy factor. Lifting a cargo up would take a lot of energy that has to be transported by other cables to the cargo-carrier, converting electrical energy to potential energy. Cargo coming down has to store that store that same amount of potential energy as electrical energy somewhere or dissipate it away as heat into space. While I like the concept of a Space Elevator, I feel that the practicalities will prevent a working structure being built for centuries, if ever.