The use of optimisation modelling for energy recovery investment decision making

Abstract

Investment decision making is a common occurrence for any engineering company. These investments include any possibility from relative inexpensive to extremely costly equipment. When power generation turbine procurements are considered for energy recovery plants, these may typically be viewed as expensive and long-term investments. Such an investment cannot merely be discarded and replaced under suboptimal conditions. If energy recovery takes place under fluctuating process flow conditions, investment choices for power generation turbines may, however, prove challenging to determine. Under conditions where resource availabilities are fluctuating to such an extent that, at times, supply outside a turbine’s operating limits are present, a number of factors need to be considered. Such decisions typically include questions regarding a turbine’s operating limits, efficiency, allowable trips, procurement cost and quantity thereof. This paper demonstrates how investment choices are influenced through the use of an optimisation investment model. A number of scenario simulations are shown, where results indicate not only what turbine investment decisions need to be exercised, but also the power generation that can be expected over time, and therefore, the true payback period. Results are presented in the form of power generation and the predicted net present value of possible investments to be made