At the 2002 IETC, Linnhoff March presented an overview of spreadsheet-based software packages to rigorously model site utility systems . Such models allow the user to plan future scenarios that might impact upon the system operation (energy saving projects, production changes, new equipment, future energy tariffs, etc). Indeed, since last year, the DOE has made utility system template models freely available to industrial users as reported elsewhere at the 2003 IETC.
Until last year, most industrial applications of this utility system software were set up for planning purposes, largely off-line. More recently, these applications have become more sophisticated and can operate on-line in real time. They include complex optimization routines to ensure that the utility system is always being operated in the best possible way under any prevailing conditions of production, energy tariffs and other variables.
These optimizer models typically reduce day-to-day utility system operating costs by between 2 and 5%.