Small difference between the yields with SolarEdge compared too Huawei configuration

[Reint]

Hi!

I have configured the same system with both SolarEdge (including optimizers) and Huawei inverters to make a comparison. It is a system with quite some losses due to shade, therefore, I expected quite a better performance of the SolarEdge configuration. However, the results are pretty close according to PV Sol:

SolarEdge + optimizers:

- Yield: 813,47 kWh/kWp

- Performance ratio: 81,0%

Huawei:

- Yield: 808,43 kWh/kWp

- Performance ratio: 80,1%

Does PV overestimate the performance of Huawei, or does PVSol underestimate the performance of the SolarEdge optimizers?

Or could this be an accurate simulation?

[Vishnu]

Hello Reint,

It is hard to say why there is no significant difference between system with SolarEdge and Huawei inverter without info about your project.

Have you tried comparing the Energy Balance sheet of both the systems?

Optimizers would definitely reduce impact of shaded modules on the whole string. But Energy Balance would give better understanding

Thanks,

Vishnu

[Reint]

I have compared the energy balances of both systems, but there are some things I can't explain. For example losses due to module-indepent shading, which are higher for the SolarEdge configuration, while this should be indepent of the configuration, right? Also I find 1,66% losses due to the optimizers quite high. The first energy balance is from the SolarEdge configuration, the second one from  Huawei.

[developer_mh]

Hi Reint,

as Vishnu pointed out already:

Quote

It is hard to say why there is no significant difference between system with SolarEdge and Huawei inverter without info about your project.

It would be good of you could provide the two project files (per private message) so that we can have a detailed look at them and explain the differences in the energy balance.

Kind regards,

Martin

[Reint]

Thanks fo the response, I sent you a private message!

[developer_mh]

Hey Reint,

thanks for the projects. Let me explain the two main aspects here.

Quote

For example losses due to module-indepent shading, which are higher for the SolarEdge configuration, while this should be indepent of the configuration, right?

In the energy balance, the losses due to module independent shading can in fact be different depending on the configuration. I know this sounds counter-intuitive, but it has to do with some logic that we use to create the energy balance.

Before the simulation, the smallest common diffuse shading value is determined for each module area. In the simulation in the radiation processor, this causes the module-independent shading. This minimum diffuse shading, i.e. the smallest common diffuse shading value, is subtracted from the diffuse shading values of the individual modules before the simulation. This enables us to determine which part of the diffuse shading is the same for all (module-independent) and which part differs from module to module (module-specific partial shading, in which case direct shading is also included). In any case, nothing is lost in the simulation, it is only evaluated differently depending on the situation.

Quote

Also I find 1,66% losses due to the optimizers quite high.

I would say this is a very low loss of energy in a DC/DC converting device. According to the database the P801 power optimizer has a efficiency curve like this:

In a wide range the efficiency is around 98.5%, which in turn explains the energy loss of 1.66%. This energy loss must be made up for in shading situations where the power optimizers can perform better than normal systems.

 

Quote

Does PV overestimate the performance of Huawei, or does PVSol underestimate the performance of the SolarEdge optimizers?

Or could this be an accurate simulation?

As pointed out, the use of SolarEdge optimizers is not per se a good idea unless you have shading situations where these devices really can outperform normal systems. The Huawei performance in these projects is good, that is true, but I can't see any sign of overestimation. It always depends on the shading and on the configuration. There are a number of threads in this forum and also conference papers that cover that topic. It is surely an interesting one, and it shows that you should always calculate those things yourself when you plan a PV system. So, as conclusion, I'd vote for the option "accurate simulation"

Kind regards,

Martin