Lookup

This technical guide explains the 'Lookup' function, which determines a dependent value based on an independent variable reference using either linear interpolation or step-wise changes. It specifies that independent values must be listed in ascending order and provides a concrete example of calculating wind power capital costs based on installed capacity.

• The Lookup function calculates a value based on an independent branch:variable reference and a lookup table. It supports two methods: the 'Linear' method, which uses linear interpolation between table values, and the 'Step' method, which assumes discrete, step-wise changes in values.
• When using the Lookup function, independent value parameters (IV) must be listed in ascending order. If the independent variable reference is less than or equal to the first independent value (IV1), the result is the first dependent value (DV1); if it is greater than or equal to the final independent value (IVn), the result is the final dependent value (DVn).
• The document provides a practical example of the Linear method applied to wind power capital costs. In this scenario, costs decrease from 200 $/kW at 1000 MW capacity to 150 $/kW at 3000 MW, and finally to 100 $/kW at 10000 MW. Under this function, a capacity of 2000 MW results in a cost of 175 $/kW, and 6500 MW results in 125 $/kW.

APA

Stockholm Environment Institute (n.d.). Lookup. https://leap.sei.org/help24/Expressions/Lookup.htm?agt=index

Chicago

Stockholm Environment Institute. Lookup. n.d. https://leap.sei.org/help24/Expressions/Lookup.htm?agt=index.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=Lookup |url=https://leap.sei.org/help24/Expressions/Lookup.htm?agt=index |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitutendlookup, author = {{Stockholm Environment Institute}}, title = {{Lookup}}, institution = {Stockholm Environment Institute}, url = {https://leap.sei.org/help24/Expressions/Lookup.htm?agt=index}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }