12 types of Losses in Solar PV system

Tania Tahseen

Tania Tahseen

Solar Performance Specialist

Losses in Solar PV System

Ever wondered why your solar plant generation becomes low after 10-15 years? Well, there are multiple reasons associated with this. Now, you must be remembering that your installers had asked you to keep your solar panels clean. It's because the accumulation of dust on the surface of the solar panels leads to lower generation. But this is not the only reason for the low generation of your system. In this article, we will walk you through all the losses that occur in a Solar PV System.

There are 12 different types of losses, which can lead to less generation:

  1. Incident Angle Modifier(IAM) loss

  2. Soiling Loss

  3. Light-Induced Degradation(LID) Loss

  4. Module Quality Loss

  5. Mismatch Loss

  6. Module degradation Loss

  7. Ohmic Wiring Loss

  8. Connection Loss

  9. System availability Loss

  10. Potential Induced Degradation(PID) Loss

  11. Inverter Loss

  12. Inverter Clipping Loss

Incident Angle Modifier(IAM) loss

Incident angle modifier loss occurs due to the tilt and orientation of the panels. The amount of solar radiation incident on a tilted module surface depends not only on the power contained in the sunlight, but also on the angle between the module and the sun.The power density will always be at its maximum when the PV module is perpendicular to the sun. Therefore it is always recommended to install the PV modules at an optimum tilt angle and in the northern region, the solar panels should always face south.

Soiling Loss

As the name suggests, soiling loss occurs due to accumulation of dust and dirt particles on the surface of the PV modules. It depends on cleaning frequency & the rainfall.

Light Induced Degradation(LID) Loss

LID loss occurs when the PV modules are exposed for the very first time to the sun. The modules are made of silicon, which is doped with n-type or p-type boron. When the modules are exposed to the sunlight, oxygen impurities in silicon react with doped p-type boron or gallium.It mainly affects the performance of the module.

Module Quality Loss

Module Quality loss is also known as module rating loss or module nameplate rating loss. It accounts for the difference in the stated power of the module from a datasheet compared with how it actually performs at standard testing conditions. Note that in the module datasheet the (+)tolerance and (-)tolerance is always mentioned. Power tolerance is a measure of electrical power a solar panel can produce above or below its rated capacity at any time. For example, a power tolerance of -5%/+5% on a 100-watt (W) panel would mean the panel could produce 95 W to 105 W under normal atmospheric conditions.

Mismatch Loss

Mismatch loss refers to losses caused by slight differences in the electrical characteristics of the installed modules. It occurs either due to different operating conditions or different internal characteristics of the cell. This results in a net decrease in power in the strings (e.g. series & parallel mismatch, different orientation of the modules etc.).

Module degradation Loss

The PV module degradation leads to reduction in solar panel output over time. NREL research has shown that solar panels have a median degradation rate of about 0.5% per year but the rate could be higher in hotter climates. A good quality solar panel will have low degradation rates that won't affect the performance of your system too greatly.

Ohmic Wiring Loss

Ohmic losses represent the voltage drop across the circuit. According to Ohm's law, the voltage drop across a circuit is directly proportional to the current flowing in the circuit. The losses faced by the circuit due to this resistance are known as ohmic losses.

In circuits, several components can cause a voltage drop, including resistors. Wires have a small amount of internal resistance.The internal resistance depends on the thickness of the wire as well as its length. It is directly proportional to the length of the wire and inversely proportional to the area of cross-section. Therefore size of the cable should be directly proportional to the current passing through it.

Connection Loss

Connection loss captures resistive losses across wiring connectors and diodes. This loss can be avoided as most solar panels contain bypass diodes. The bypass diodes are connected in parallel with solar panels. It creates a path for the current to flow around them in case the panels become faulty.

System availability Loss

This loss generally takes place in ON-Grid and Hybrid solar systems. As the name suggests this loss occurs when there are grid outages, inverter shutdown or failure. Due to unavailability of the grid, the power doesn't get exported leading to loss of power.

Potential Induced Degradation(PID) Loss

Potential Induced Degradation loss occurs when pn-junction of cells gets destroyed due to cracks on the module. Moisture gets inside the modules which leads to leakage in the conductivity of the cells. Charges that should go to the inverter gets deposited on the aluminium frame. Gradually solar cells become inactive which leads to losses.

Inverter Loss

Inverter loss is the DC to AC conversion, this loss occurs when the inverter converts DC power to AC power. This loss depends on Inverter efficiency which can be described as how well a solar inverter converts DC energy into AC energy.

Inverter Clipping Loss

This loss occurs when the output from the direct solar panels (DC) at their maximum power output(or maximum power point) is greater than the amount of DC power the inverter can convert. The amount of energy production lost(or clipped) compared to what the system would have produced if it had not been limited by the inverter rating is called inverter clipping.

Don't worry about all these losses. We already take these losses into consideration, before promising you the amount of energy your solar plant will generate.

Also Read: Does Solar Panel installation make my house more valuable?

Tania Tahseen

Tania Tahseen

Solar Performance Specialist

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