
A key aspect of monitoring and targeting is the calculation
of expected consumption for comparison
with what was actually used.
One good way of doing this (but not the only way)
is to relate consumption
to some driving factor using a straightline relationship
as illustrated here.
The typical driving factors for energy consumption (in simple
cases) are things like:
Realworld complications: not every process conforms to the ideal of a straightline relationship between consumption and a single measurable driving factor. Follow the links to learn about: Whatever the situation, we will have a mathematical formula into which we put the measured drivingfactor values in order to obtain an estimate of expected consumption. This is called the expectedconsumption formula (ECF). 
ECFs can be used for different purposes by adjusting the constants used in the formula. Where a straightline model is used, these constants are the slope of the line and the intercept on the vertical (energy) axis. By setting these as low as possible, the performance characteristic represents best achievable performance and would be used for routine exception reporting. Click here to learn how to set the characteristic line at the lowest feasible position.
Another important characteristic is the historical baseline. This represents behaviour as it was at the start of your energysaving programme and it uses the same ECF as the target characteristic, but with any constants set to represent performance as it was at the time.
In general each consumption stream has just one ECF but this may be "set" to compute expected consumption for whichever purpose is needed (operational target, historical baseline, budget projection, etc) by using different values for the constants in the ECF.