Storing hydrogen underground for long periods is actually shockingly cheap. It's the same technology used for storing natural gas underground. The cost is as little as $1/kWh of storage capacity. This is already proven technology, so no whining about embrittlement please.
Yes, it fits edge cases -- but it has an outsized effect on the cost of a 100% renewable grid. Trying to cover black swan events with batteries or overprovisioning would be much more expensive. Optimizing baseload output in Germany using historical weather data and 2030 estimated cost figures for PV, wind, batteries and hydrogen, including hydrogen cuts the cost of the system in half.
PV, wind, batteries and hydrogen ignores hydroelectric generation making such numbers pure fantasy. Of there where any need to do so we can use them for seasonal storage simply by not using them when doing so is unnecessary.
I don't think hydro can displace hydrogen for these applications. In particular, I don't think hydro has enough energy storage capacity to provide seasonal load leveling in many places.
Yes, it fits edge cases -- but it has an outsized effect on the cost of a 100% renewable grid. Trying to cover black swan events with batteries or overprovisioning would be much more expensive. Optimizing baseload output in Germany using historical weather data and 2030 estimated cost figures for PV, wind, batteries and hydrogen, including hydrogen cuts the cost of the system in half.