ASTM e2939 Made Simple

ASTM e2939 is part of a protocol to establish whether a solar power plant is operating at it’s expected capacity. ASTM e2939 is paired with a second ASTM protocol - ASTM e2848. The protocol describes a process for assessing a plant’s capacity and likely weather conditions based on an 8760 file. 8760 files are generated via a modeling program, (most often PVSyst).

ASTM e2939’s can be generated anytime after the PV Syst is created. When possible, we advise completing the ASTM e2939 step before a contract is signed. This is best practice, but rarely the case. But because e2939 effectively establishes a baseline for success, it’s an important part of the discussion of expectations between EPC, O&M team, developer, and site owner. If a PV Syst is available and agreed upon as part of the process, conducting e2939 early can dramatically reduce disagreements and speed up project closeout.

Because e2939 is part of a bigger process of establishing solar site capacity as part of overall performance testing, it’s best to understand the full process.

You can check out a step-by-step process for pairing both ASTM protocols here.