Solar farm integrated with BESS

[Afshin]

What steps can we take to ensure that our system prioritizes charging the Battery Energy Storage System (BESS) before supplying excess power to the grid? I'm particularly interested in achieving a scenario where the power supplied to the Electrical Grid (E_Grid) approaches zero, while the majority of the kilowatt-hours (kWh) are stored in the Battery (E-Bat) in the following result table. 

 

[Linda Thoren]

Dear Afshin,

For a Grid-connected system with energy storage, any excess power will be stored in the battery before supplying energy to the grid. If the battery storage is fully charged, you have the choice to inject power to the grid or not by ticking the box “Allow solar injection into the grid” in the Operating conditions box.

Regards

[Afshin]

Thank you! Actually, I wanted a scenario that the PV system charges the batteries first and then if we have extra power, we can feed the grid. For example, I have 2-MW solar system and 10-MW BESS. I need to first charge the BESS completely. 

[Linda Thoren]

In PVsyst we have 3 strategies for Grid-storage. In the Self consumption strategy, the produced electricity from your PV system will firstly supply the user’s need (consumption), secondly charge the BESS and lastly supply energy to the grid. With the Peak shaving strategy doesn’t involve an internal use of the energy and you can define the operating conditions such as Grid power limit and discharging. In the Weak grid islanding strategy, you define the Grid unavailability and your storage pack is meant to fill up for the times when you have no production from your solar panel, nor power from the grid.

You can read more about this in the PVsyst help in the following link:
https://www.pvsyst.com/help/grid_storage.htm

Or watch some of the youtube-videos we have on the topic:
https://www.youtube.com/watch?v=-PGRnnF1VuA&list=PLxdyykgAqoynTXUHWrdCxPSYLkhJ9mW7c

https://www.youtube.com/watch?v=49d5pAV907Y&list=PLxdyykgAqoynTXUHWrdCxPSYLkhJ9mW7c&index=3

https://www.youtube.com/watch?v=jZKdz248WJQ&list=PLxdyykgAqoynTXUHWrdCxPSYLkhJ9mW7c&index=4

Regards

[Rhett]

Hi, 

I am just following the thread, I have the same question.

Peak shaving in my mind is about generating revenue as an IPP by manipulating the time of use tariffs. This means that charging the battery should always be a priority to ensure it can be discharged in the peak time of use period. I understand the strategies PVsyst uses but this does not coincide with the industry per se. 

I am trying to design an 8.2MW plant with 2.5MWh of storage to be able to discharge in peak, particularly in winter where the peak tariff costs 3 x more than the summer peak tariff in South Africa. In winter I get zero values for the battery discharge when I run the simulation. I know why this is but it does not make sense as it is not a true reflection of how the plant would be operated. I would always prioritize charging the battery first with any excess power being evacuated to the grid. 

 

Is this something PVsyst is taking into consideration for near future versions, because at present it is a limiting factor?

[Linda Thoren]

Hi!

Thank you for your input and concrete example. In PVsyst, peak shaving has primarily been developed as a strategy to manage scenarios with grid limitations by shifting the production peak, rather than as an economic strategy for discharging at peak prices or peak electricity consumption. Further development of storage strategies is planned for next year.

Kind regards

[Rhett]

Hi Linda, 

Thanks for your prompt reply. I look forward to the updated version of PVsyst that can take this into account as this is where the industry is moving towards.

Regards