The Cost of Battery Storage

Batteries which Elon Musk seems to believe the great hope of the grid in fact you don't need anything else. You just litter the land with thousands and thousands of gigavacories of various descriptions and storage facilities is that realistic? Well hydrogen there's another possibility isn't it but let's call it a possibility because you know I think that could well be something for the future where you use surplus electricity wind and solar. When when you grid can't absorb it you use it to produce hydrogen via electrolysis of water and then you store the hydrogen and then you burn it when you do need the power. It would be very difficult to earn that money back earn your investment back as we