SPECs Early-Stage Decision Model: User Manual

Christian Casillas, Simon Sandler, Jill Cliburn, Sara Farrar (NREL Technical Monitor)

Research output: NRELSubcontract Report


The SPECs Early-Stage Decision (ESD) model is central to the SPECs procurement solutions toolkit. The ESD model is an Excel-based spreadsheet model, which provides information about the economic and strategic value of a proposed battery-storage project or solar-plus-storage (solar-plus) project. The model can be used to explore combinations of storage-related project value streams in order to define a potential project, while educating co-op decision-makers about project benefits and costs. A sensitivity analysis function speeds the development of "what-if" scenarios. A gap analysis function solves for top-priority metrics and supports the inclusion of hard-to-monetize strategic values, such as the value of storage to defer costly system upgrades in light of increasing distributed solar and other distributed energy resources (DERs). Model outputs include the utility data, assumptions, and use-case scenarios that are recommended content for the requests for proposals (RFPs). The model may also provide an initial "sanity check" for RFP responses, supporting further discussions among utility staff, vendors and stakeholders. The ESD is not a "finance-grade" modeling tool, and users are cautioned to be mindful of its limitations, but the model has been reviewed by users, who recommend it as a way to drive faster and better project design and planning, as well as to facilitate better communications with vendors, grid partners, and stakeholders.
Original languageAmerican English
PublisherNational Renewable Energy Laboratory (NREL)
Number of pages46
StatePublished - 2024

Bibliographical note

Work performed by Cliburn and Associates, LLC, Santa Fe, New Mexico and North Carolina Clean Energy Technology Center, Raleigh, North Carolina

NREL Publication Number

  • NREL/SR-7A40-90018


  • battery storage
  • decision model
  • demand charge
  • energy storage service agreement
  • ESA
  • PPA
  • project design and planning
  • SAM
  • solar power purchase agreement
  • solar+storage
  • System Advisor Model


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