What is kWp?
kWp or kilowatt peak refers to the measure of power from solar energy panels or devices under standard testing conditions. It is also called as “peak power” or “nominal power” representing the output that may be provided by a particular solar module in conditions wherein there is full solar radiation. In this context, standard testing conditions refer to 1000 watts of solar power per square meter. But since kWp or peak power is generated under laboratory conditions, its value shouldn’t always be the same in conditions involving actual amounts of radiation. In many solar devices and panels, the discrepancy in power output may reach up to 20% less for actual conditions.

Standard test or laboratory conditions are used to compare different solar panels and devices from different manufacturers. Through standardized testing, consumers are able to analyze for themselves which solar panel is better or which panel can generate more power. Peak power or nominal power of a particular solar panel can be determined through measurement of the voltage and current while altering the resistive load under a specific amount of illumination.

But in terms of the efficiency of solar panels, it may take some computation for consumers to know which manufacturer produces the better product. The kWP rating is always a present feature on the manufacturer’s data sheet, but the efficiency rating is almost always not part of it. But for simplicity, one can get the efficiency rating by getting the kWP rating and dividing it over the panel’s surface area.

When comparing different solar panels, one must note that it is best to study the fine print on the specifications of the particular product. Aside from the kWP and efficiency ratings, it is also good practice to know the products performance warranty. It would be easier to decide if the products we purchase are manufactured and supported by companies that we think will still be around in next decades or so for servicing issues.