What is the advantage of a fixed-rate energy plan?

When you sign up for a fixed-rate plan, you are locked in a specific rate for the length of the contract term. This rate is based on what Direct Energy thinks the market will behave like over the length of the contract term; and thus, you are protected from price fluctuations you could experience on a variable-rate plan due to unexpected market conditions (whether extreme weather, hurricanes, shortages of supply, etc).