Modeling electrolyzer OffsetTransformer/ PiecewiseLinearTransformer

hey everyone,

I would to model hydrogen system using Oemof containing an electrollyzer, fuel cell and storage. I see in the documentation in order to work with OffsetTransformer (to model an electrolysis process with different efficiencies in part load condi!on.) we have to define the P_out_min and the and the P_out_max to calculate coefficients of input-output line equation.
However what I’am actually aiming to do is a dispatch op!misa!on based on costs using the investment mode. so my question it’s possible to use OffsetTransformer and considering the investment mode.

Besides to the OffsetTransformer there is the PiecewiseLinearTransformer component. for example in order to model an electrolyzer I need to define the in_breakpoints which basically depend on the nominal_value (max electrical input power off the electrolyzer). Again The goal consists of determining the optimal capacity using the investment mode and that’s makes me confused,

I’am grateful for any help.

I have not worked with the PiecewiseLinearTransformer so far but I am pretty sure that the OffsetTransformer does not work with investment. There are three kind of flows in solph. Normal flows, investment flows and non-convex flows. It should not be a problem to create a non-convex-invest flow but it has not been implemented so far.

You could add one with the help of the community but it depends on your skills and your time horizon (less skills → more time :slight_smile: ). This is how solph works, people add what they need and other users in the future will be happy about it…

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alright I understand! I’m convinced that this option to habe OffsetTransformer with investment would be enormously useful! That’s the point I would love to contribute developing that however I still have acquire more knowledges and skills to achieve that :smiley:

Thank you Uwe!

There is a developer meeting in December (1.12. - 3.12.) in Bremen. So if you are planing to use solph in a long-term (not only a Master’s thesis) you could get some help there. With some hints it is less complicated than you may think.

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Hi @jess, @uwe.krien and everyone!

I am working on a similar problem to model a hydrogen system with an electrolyzer, storage and fuel synthesis unit in Oemof. Did you finally manage to model the part-load behavior of an electrolyzer using an offset transformer or a Piece-wise linear Transformer? My goal is also to determine the optimal capacity using the investment mode. Which kind of Transformer is better suited for this application?

Thanks in advance!
Nouman