Introduction

Overview#

A Capacity Test is a short-term test that reports the power output of a solar asset relative to its Expected model benchmark. In the context of the asset's lifecycle, a Capacity Test is typically conducted around its initial operation or "Commercial Operation Date" (COD) as a condition of the project's substantial completion. Counterparties typically include Engineering, Procurement, and Construction (EPC) contractors, project owners, financiers, and representative Independent Engineers (IEs).

Denowatts offers an ISO/IEC 17025 Accredited Capacity Test Report that follows ASTM E2848 (ASTM) and IEC 61724-2 (IEC) reference standards through its software and hardware. Subscribed users may download the test report through the Denowatts User Portal with the flexibility to use either default parameters or conditions that may be predefined in their project contracts.

Key Benefits#

1. ISO Accreditation. No more concerns about whether the standards are followed. Denowatts is an ISO/IEC 17025 Accredited Testing and Calibration Laboratory. This means users can be confident the test report follows the highest level of bankability in the world, including detailed measurement uncertainty analysis, annual accreditation audits of laboratory practices, and annual proficiency testing by peers.

2. System accuracy. No more doubt about sensor accuracy and alignment. Denowatts reduces test uncertainty by managing the process from Deno sensors calibration and installation commissioning, customer model benchmarking, and meter and inverter data validation.

3. Streamlined process. No more Excel test reports and arguing about valid points. Denowatts carefully follows the standards, integrates with contractual requirements, and incorporates software to make the process repeatable and replicable using a simple user interface and instantly downloadable reports.

4. Independent reporting. No more concern about counterparty bias. Denowatts independently represents the project with impartiality, which is part of ISO/IEC 17025 Accreditation. Denowatts cooperatively works with the EPC through installation and commissioning, reporting interim results until the test is complete. If tests show unexpected results, Denowatts supports all counterparties with root cause analysis, such as equipment unavailability, modeling error, and design oversight.

5. Comparative analysis. No more questioning model accuracy. Though capacity test standards presume that models have no error, this isn't always the reality. Denowatts provides comparative test results using both ASTM and IEC methodologies, as well as proxy single-diode and point value models. When comparative results align, users gain confidence in the test. However, when comparative methods and models do not align, the differences can provide insight into the root cause.

6. Root Cause support. No more hunting for answers to failed tests. Part of Denowatts' ISO 17025 Accreditation is to provide root cause analysis for test failures, which can be from underperformance or overperformance. Denowatts employs Energy Accounting, comparative modeling, and benchmark commissioning to assist in quantifying variations from expected results. Process Summary

Capacity Test Process#

Capacity Test steps include:

1. Contractual Agreement between counterparties, which defines the test methodology, measurement equipment, customer model, soiling and shading allowances, and passing criteria, such as score, minimum test points, and maximum uncertainty. Denowatts offers an example Capacity Test Exhibit that can be downloaded here.

2. The customer energy model is uploaded to Denowatts portal. If using PVsyst, Denowatts requests the full Project.zip file with the test-defined variant.

3. Measurement Equipment setup, including Deno sensors placement and commissioning, and connection to the production meter and inverters.

4. The testing period may begin as soon as Steps 2 and 3 are complete. Users may track the real-time progress of the test results in the Denowatts portal, including input settings that follow the specific parameters of the contract. Users may elect to results reported that follow either the ASTM or IEC standards, as well as defined test parameters, including test boundary, target reference conditions (TRCs), filters, and shading and soiling allowances.

5. ISO/IEC Accredited Test report download, a .pdf document that includes test score, measurement uncertainty budget, comparative analysis, calibration certificates, and customer model summary. The test report includes requirements of the ASTM E2848, IEC 61724-2, and ISO/IEC 17025 reporting requirements. Note: Denowatts does not provide PASS/FAIL results, which is typically the interpretation of the counterparties and their IEs.