SPECs Early-Stage Decision Model
The Early-Stage Decision (ESD) model is a software tool designed to screen solar and storage projects, to fine-tune their design, and to facilitate their procurement by local electric co-ops and public power utilities. A new version of the model, recently released supports acquisition by contract (PPA/ESA) or direct purchase, including access to incentives that were extended to non-taxable utilities under the Inflation Reduction Act (IRA) of 2022. Other updates include facilitating grid charging as well as solar charging, as the IRA supports greater system optimization.
In short, the ESD model is a response to the adage, "You can't get what you need unless you know what to ask for." With guidance from an introductory training video and a detailed and updated user's manual, this tool can prepare local utility staff and decision makers to get past early "go/no-go" decisions, to test impacts of rate or policy changes, to create better RFPs, and to engage more fully with expert consultants and industry players in later stages of the procurement process. As shown below, the ESD streamlines the complex challenge of applying battery storage and solar-plus to capture multiple values–a frequently misunderstood concept called value stacking. The ESD model dovetails with the NREL industry standard tool for solar project modeling, the System Advisor Model (SAM). Users may download the ESD model, along with the script link to SAM and user's manual, at no cost. Utilities and other users may learn about additional training opportunities and fee-for-service support from Cliburn and Associates and the North Carolina Clean Energy Technology Center, which co-created this tool. |
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The ESD model is designed for use and review by non-specialized staff and decision makers. Steps include:
Note that the ESD model is designed for education and early-stage decision-making. It is not intended and should not be used as the basis for investment decision-making. Upon downloading the model, users must accept Legal Disclaimers on behalf of Cliburn and Associates and the Solar Energy Innovation Network, which co-funded its development. For more information on using the model, including recent updates, please e-mail us here.
- Define the project use case, including up to three targeted value streams.
- Complete a preliminary analysis, with emphasis on solar generation and local demand reduction, via a ready link to the NREL System Advisor Model (SAM).
- Review the user's manual and model, setting, estimating or choosing default values for key assumptions needed for the initial economic analysis and later fine-tuning.
- Incorporate strategic values, e.g., distribution upgrade deferral or resilience/microgrid value, through an optional gap analysis that can help decision-makers to support a strong project plan.
- Review results and use the sensitivity analysis function to speed project fine-tuning.
- Export key assumptions and anticipated results to support development of the project RFP.
Note that the ESD model is designed for education and early-stage decision-making. It is not intended and should not be used as the basis for investment decision-making. Upon downloading the model, users must accept Legal Disclaimers on behalf of Cliburn and Associates and the Solar Energy Innovation Network, which co-funded its development. For more information on using the model, including recent updates, please e-mail us here.
The SPECs updated Early-Stage Decision Model User's Manual (Version 4, 2022) guides users through basic solar-plus-storage principles and step-by-step through ESD modeling. The manual is a necessary companion to the model itself, including definitions of terms, suggestions for data collection and methods for setting assumptions. It also includes guidance on running the gap analysis and sensitivity analysis functions. Appendices provide information on battery operations and degradation and regarding the use of NREL's SAM model as a preliminary analytic step. The manual includes an updated section on how to manage pricing uncertainty, which has been characteristic of recent years. The model logic for each use case is included to support customization, and references help to make the manual broadly and specifically educational. While the ESD User's Manual Version 4 is fully updated, please note that our training webinar (below) predates Version 4. We still recommend that training, as the content is entry-level and fully relevant to the current ESD model.
| esd_manual_final_version_4.pdf |
One of the more vexing challenges of any early-stage modeling is to estimate pricing inputs. The RFP process, which follows early-stage project modeling, typically provides the utility with its first real look at pricing for the specific size, scale, and functionality of its solar-plus-storage project. For the purpose of early-stage modeling, there are proprietary sources for current pricing data, but publicly available information may be sufficient. At the early stage, the utility should focus on understanding value drivers and defining break-even costs. For the release of Version 4 of the ESD and Manual (2022), the SPECs team has noted that solar and storage prices have been volatile and temporarily rising. The model includes a sensitivity analysis function, which shows the range of prices that could achieve cost-effectiveness for specific system configurations. The User's Manual Version 4 also includes additional guidance, culminating in an RFI or RFP. It also provides suggestions and references for comparing direct-purchase pricing to PPA and ESA (service contract) pricing.
The slides provided below were part of a presentation to the SPECs team by Berkeley Labs' Mark Bolinger, offering perspective on solar-plus-storage pricing for projects in the range below 20 MW. A related, 2021 cost-projection analysis from NREL is available here.
The slides provided below were part of a presentation to the SPECs team by Berkeley Labs' Mark Bolinger, offering perspective on solar-plus-storage pricing for projects in the range below 20 MW. A related, 2021 cost-projection analysis from NREL is available here.
Current solar-plus-storage levelized pricing data
is discussed in an updated Berkeley Labs publication,
Hybrid Power Plants: Status of Proposed and Installed
Projects (August, 2021). The image here indicates that, while project design and pricing in Hawaii is an exception, the levelized pricing (2020 $/MWh-PV) for hybrid systems is relatively consistent across the U.S. in recent years.
| bolinger_storage_slides_copy.pdf |
| hybrid_plant_development_2021.pdf |
Downloading Version 4 of the Excel-based ESD Model and SAM Import Link
Users that have experience with basic, spreadsheet-based economic models will recognize the ESD model format, with similar general inputs and data tabs. The opportunities to choose a value stack scenario (use case) and to set or choose defaults for battery-related inputs are unique, and are at the heart of the model's capabilities. The model also guides users through an optional gap analysis process, which incorporates strategic values. Further, the model has a sensitivity analysis function. The user's manual, linked above, provides important and easy-to-follow instructions on how to incorporate a basic NREL SAM analysis into the ESD model, tapping SAM's ability to analyze solar technology options and to incorporate location-based and weather/resource data sets. The link, sam-to-esd.lk should facilitate this (html is provided below). SAM offers many features, including a well-supported way to assess battery storage for demand-cost reduction; however it generally takes a commercial-customer view, rather than the utility's perspective. The ESD model builds on SAM capabilities for local utility use. Further, the ESD includes basic updates for the impacts of the Inflation Reduction Act of 2022.
Watch this site or Contact us for more details on the upgrade for Verson 4 of the ESD.
Watch this site or Contact us for more details on the upgrade for Verson 4 of the ESD.
| specs_v4.0_9.23.2022.xlsm |
| sam-to-esd.lk |
By clicking on the contacts here, users may learn about additional training opportunities and fee-for-service support from Cliburn and Associates and the North Carolina Clean Energy Technology Center, which co-created this tool. Although the model is provide free of charge, it is provided "as is," and under Terms of Use that are detailed on the model landing page. Users are assumed to have accepted the ESD Model Terms of Use.
Webinar: How to Use the ESD Model
This webinar features ESD model co-authors Christian Casillas and Simon Sandler, with moderator Jill Cliburn, in a live walk-through of the model, Version 3, using a hypothetical electric co-op storage project to demonstrate how to model a use case that has multiple value streams and that includes the strategic value of co-op distribution infrastructure deferral. The video is a "quick-start" guide to the ESD model, and is further supported by the user's manual, described above. Version 4 users will find this video generally applicable; major changes refer to the addition of a new use case in Version 4 and solar and storage incentives in the IRA, which broaden cost-effective options for many local utilities.
| 2021_06_10_esd_video.pdf |
Acknowledgements and a Disclaimer, which are required on the U.S. Department of Energy funded portion of this work, are included on under the About/Project tab of this website. Users of all resources and information on this site are cautioned to perform due diligence in adapting content to a specific local project or opportunity.