A typical scope of Conceptual Engineering encompasses Preliminary Project Planning and Preliminary Cost Estimations, to identify if the project is feasible, or whether the necessary equipment or processes are available in the marketplace.

Aiming to have the Preliminary Cost, a usual method is the Bottom Up Estimating, which builds the overall cost estimate by summing estimates of several “building blocks” and processes, on a Work Breakdown Structure (WBS) perspective. Through this method, the system being costed is broken down into lower-level structures (such as sub-systems and equipment) and each of which is costed separately.

The cost estimator must have an extensive knowledge of the system’s characteristics and the minimum technical attributes from each “building block” on a conceptual perspective. Because of the high level of uncertainties in the Conceptual Engineering, each step of the work flow should be identified, measured, and tracked, and the results for each outcome should be summed to make the point estimate.

Some advantages of the Bottom Up Estimating include: the estimator’s ability to determine exactly what the estimate includes and whether anything was overlooked; its applicability to a specific project and/or manufacturer; a good insight into major cost contributors; and easy transfer of results to other projects. Although the Bottom Up Estimating Method faces some drawbacks, it’s a well-known and validated method for Conceptual Engineering Cost Estimation, when highly complex systems are involved.

By Débora Calaza
Process Engineer at Deep Seed Solutions