Fixed pricing allows you to lock in the rate you pay for electricity with a contract for a given time period, usually 3-60 months (depending on your selection).
Variable pricing, also known as Month-to-Month pricing, may fluctuate with the energy markets. There is no contract in a variable plan. Your pricing could go up, stay the same, or even go lower, all of which is out of your control and is determined by the energy company offering the variable plan.