[rurban]

What everybody misses is the different need during the spikes due out the day. In the morning and at noon the grid needs for a short time a massive amount of energy, which can only be provided by such "pump batteries". That's why Austria can sell this peak energy at much higher prices. On the other side the new northern german wind energy cut the prices dramatically on the non-peak hours.

My idea on this was to use the batteries of the new electric cars to store energy and take it for the peaks. This would need cooperation with the carparks of the big companies to provide free battery loading during the day vs sucking off peak voltages in the morning and at noon. In the late afternoon the battery must be full, what happens in the morning and at noon is for the grid. This solves the electric car problem, and the grid problem with not enough north-south lines.

[Bluestrike2]

That kind of integrated approach--with vehicle-to-grid power flow alongside more general coordinated charging--could have clear advantages, especially given the possible growing pains from uncoordinated charging.[0][1] V2G isn't a new subject; it's been around for a while now, and the UK even announced a large research grant on the subject earlier this year.[2] Most of that research looks at V2G in terms of how it can be used to help mitigate the impacts of EV charging in particular and short-term spikes associated with them, rather than say general grid storage. So it's more of a longer-term matter, than the immediate concerns of building out storage capacity.

One of the biggest difficulties is going to be dealing with the economics of battery degradation. You can limit the pull on any given battery to somewhat lessen the impact, but doing so also limits V2G's impact on the grid. Presumably, utilities would pay for battery usage. If so, how does that affect the economics: I can't say either way, but I'd expect the marginal cost of 'renting' EV batteries to be greater than just buying your own for dedicated storage.

0. http://iopscience.iop.org/article/10.1088/1748-9326/aabe97/m...

1. https://www.nature.com/articles/s41560-017-0074-z

2. https://gtr.ukri.org/projects?ref=133490