impose that EV battery charge link is equal to vehicle-to-grid link

[martavp]

for this toy model, similar to that included in pypsa-eur-sec
https://github.com/PyPSA/pypsa-eur-sec/blob/e3ffb66267c324b259b4a3db2cf03a3a642044c6/scripts/solve_network.py#L169

[BertoGBG]

my understanding of V2G at vehicle level is that the allowed discharge power will be much lower than the charging power to preserve that battery. There will be some sort of cap.

I think that we should introduce this cap, either as p_max_pu or p_nom_max on the V2G link.
just to be future proof. if don't want to use it we set it equal tot the EV charging link.

I think that this is important to have a cap because we don't have battery degradation in our models and if we don't cap the V2G at all we could end up using this feature well beyond technology limits.

[martavp]

Hi @BertoGBG

Thanks for your remarks.

We need to remember that the EV battery charge link (and the v2g link) does not represent one car but all the cars in one of the nodes (e.g. a country). This "lumped" model of EVs is of course a simplification aiming to represent how a myriad of cars will interact with the grid.

In this case, we don't need to implement a limit to represent what one car does to preserve the battery. I think this is a good approximation

This is similar to when we use a generator to represent all the nuclear power plants in a country. We don't need to include ramping constraints because, when aggregated, the change of nuclear power is not limited by what one power plant can do.