You can not lose energy, nor can you be in short supply. The amount of energy in our environment is so great that it is beyond our comprehension. Energy is measured in joules , in honor of the British scientist James Joule. One joule is roughly the amount of energy required to lift an apple from your kneecap over your head. A gallon of gasoline has over 200 million joules of energy.
Work is the mechanism that transfers energy through a system.
It is produced by applying a force on an object such that motion occurs over a distance. For example, when you pick up a book, you have performed work on the book.