Relative Targets are percentages of some time in the past that "move" with the information (eg "no more that 80% of this day last month")
Fixed Targets are fixed values that are compared against total daily, weekly or monthly usage (eg "no more than 400kWh per day")
Day Profile Targets are daily hour-by-hour patterns generated by an analysis of past data. Day profile targets can be manually adjusted to create a profile that matches what you believe your daily consumption patterns should be.
Regression Targets use Regression Analysis on an associated independent variable i.e. production units to calculate what the target energy usage should be.