Differences between peak power and rated power
Nowadays, on a solar panel installation project, it is necessary to find out about many things. An important point to know is that there are two types of power: peak power and nominal power.
The inverter, the device in charge of transforming direct current and alternating current, is vital to understand the difference between the concepts that we are going to deal with in this article; since the nominal power refers to the power of the inverter, while the peak power is that corresponding to the solar panels.
This difference in power affects the production of our installation and we will explain why below.
Rated power
Regardless of the total amount of energy that the plates can produce, the inverter is only capable of managing a part of it, which corresponds to the nominal power. In other words, it is not possible to consume more energy than the inverter can transform.
Having reached this conclusion, it is normal to wonder why we have to install more peak power if we can only reach nominal power. The reason is simple: so that the inverter can work at one hundred percent of its capacity.
Power doesn’t go from 0 to 100 instantly, it’s produced by following a power generation curve: it builds up until it hits full power, and then it starts to drop. Therefore, there is always an energy margin between the two powers that we can take advantage of for our consumption, taking full advantage of the inverter’s capacity.
Peak power
To know the peak power it is necessary to know how much power the installation can produce and this depends on certain factors. The peak power, as we have already mentioned, is the maximum power that they will have. To measure it, the maximum power that a plate can generate under standard conditions is calculated, such as: a temperature of 25 degrees, an irradiation of 1000 W/m2 and an air mass of 1.5.
Air mass is the distance that solar radiation travels when it passes through the atmosphere. This figure, the air mass, will vary according to the angle at which the sun’s rays hit. This information is important, since they greatly influence the performance of the plates. The optimal incidence would be perpendicular.
In short, the peak power is the maximum power that can be achieved with the climatic and installation conditions that we have described. But be careful, this does not mean that in other conditions the installation cannot produce even more electricity, for example, on a very sunny day with an ideal incidence of sunlight.
With these data it is possible to check the power of the installation, which is calculated in watts and peak watts. This last concept is used to calculate production peaks and check the power of the plates at all times, all to better understand the operation of the installation.