One other development which is common now, is pumped hydro, where the water is pumped back up to the damn using off peak power (when electricity is cheap) and then generating the electricity during peak times. This is effectively a battery, and is a really good addition to an electricity grid particularly with wind and solar which aren't generating all the time.

You're welcome @notak, Actually, I'm not familiar with this technology yet, but the system works interestingly. I think this can be an alternative in the future. I also had time to watch on the Chanel Financial Times about the development of this technology in Australia, your tech innovation is developing very fast..