What Is The Role Of Lipids In The Human Body?

The role of lipids in the human body is for energy storage. It produces a great deal of energy upon oxidation and therefore are efficient forms of energy storage. Lipids as mentioned, plays a role in insulation for the body. And also is important for cell membranes. For example Cholesterol is the starting synthesis of all steroid hormones and plays a role in fluidity and increases the permeability to ions...Also Phospholipids (the most abundant membrane lipids) that make up the lipid bilayer of the cell membrane are important to membrane structure as it allows specific molecules to pass across, keeping unwanted substances out- acting as selectively permeable.

Well, lipids are kind of, but not really stored in the liver...
 
The main purpose of lipids is to act as energy storage. The body generally uses carbohydrates as a direct form of energy, and stores energy as lipids. When the body has too much carbohydrates to use all at once, many of them are taken to liver, and changed into lipids by special cells there called hepatocytes. The liver does store some of these, but so do most other cells in the body...
 
Another purpose of lipids is to make up, and give structure to the membrane of cells. Namely, cholesterol. Substances called phosolipids (which are half lipids) make up the vast majority of the cell membrane.
 
They also provide many other roles in the body, such as providing warmth via insulation, they act as signilaing molecules from cells to other cells etc, etc. If you need any more information just ask.

Lipids play an important role in the insulation of the body, cushion of the bones and joints, cellular maintenance, and energy throughout the body- remember it yields the mose k/cal's per gram.