Fletcher Challenge Paper owns and operates an integrated newsprint and kraft pulp mill in New Zealand's eastern Bay of Plenty, commonly known as the Tasman mill. The mill has an average electrical load of 170 MW. Three steam drawing turbo-alternators are operated on site, which are able to generate as much as 40 MW. The remaining electricity required is purchased.

Steam Plant operations staff are responsible for managing the supply of steam to the pulp and paper mills, and also internal electricity generation. Operational conditions, such as steam requirements, vary continually. When coupled with varying electricity price forecasts, this fluctuation produces a complicated set of trade-offs.

A decision support tool has been running in the Steam Plant control room since early March 1999. This tool is commonly known as SPOT, or Steam Plant Optimisation Tool. SPOT is a linear program which uses real time operations data, and the latest half-hourly electricity price forecasts to produce an optimal plant operating strategy.

This paper describes the nature of the Tasman Steam Plant operations, the formulation of the SPOT model and a description of its implementation.