By Evan S. Riley, Renewable Energy Consultant, Black & Veatch
Using a prescribed test protocol to compare the measured performance of a solar PV power plant relative to its expected performance is often a means by which the value of the facility is determined. Performance testing is used contractually to determine matters such as the fee paid to a constructor, the price paid to a seller, and the cost of capital from a lender or investor. To ensure that performance testing produces consistent and independently verifiable results, it is essential that accurate and repeatable test methods be used. This paper outlines critical deficiencies in older solar PV performance testing protocols, and how the methods prescribed in ASTM E2848 and E2939 eliminate these deficiencies and enable test practitioners to produce consistent, verifiable results with a high degree of confidence.