Proposal to amend UN GTR No. 21 in a consolidated version. The document establishes a worldwide harmonized method to determine system power rating for electrified light-duty vehicles comparable to traditional measures for conventional vehicles. It specifies two test procedures: TP1 based on measured electrical power and estimated ICE power, and TP2 based on measured torque and speed at axles or wheel hubs. The GTR introduces the reference point concept to identify where mechanical power is first produced from stored energy, establishes applicability rules for each procedure based on powertrain architecture, requires manufacturers to provide verifiable K factors and hybrid power flow descriptions, mandates five test repetitions with averaging of the last four results, and adds internal validation criteria. The procedure aligns measurement accuracies with UN GTR No. 15 and permits use of validated onboard data where accuracy is demonstrated.