Even a firm as committed to hydrogen for energy as DNV is, using oil and gas analysts who won't have a job if hydrogen doesn't become a dominant energy carrier, can't make it make sense in their reports as hard as they try.
Honestly, dumping any renewable surplus into water electrolysis admixing produced hydrogen to the natgas grid beats curtailing. You've already paid for the infrastructure, and as capacity increases failure to do so will only hurt more in future.
There are lots of less expensive, higher impact ways to use surplus electricity to decarbonize. Spending money on upgrading fossil gas infrastructure and electrolysers to run at 10% duty cycle is well below even building more power generation and curtailing more in terms of cost effectiveness.
Photovoltaics capacity factor is about 10% of nominal peak where I sit, so you will have to build out massively which will put you far in excess of those current 50% renewable electrivity peaks in Germany. There simply isn't a cheaper way to capture these peaks as there isn't even transport infrastructure for electricity. Alcaline water electrolysis is stupid cheap and the natgas grid is already there. Price isn't a good argument versus curtailing. And natgas availability in future is rather uncertain.