It looks like dasylirion longissimum to me. Not a grass, but an agave relative. Also possibly a nolina of some sort.

Looks a bit fine and flexible for D. longissimum, which gets very large.

Could be Nasella tenuissima pre-bloom. Not a recommended grass because it reseeds like crazy.

If you want an nice fine grassy plant of about that height, look at something in the genus Lomandra. Some of them are quite drought tolerant. Carex testacea is another fine-bladed clumper, but it has a more arching habit and orange highlights.

Here is a link that might be useful: lomandra page

I also think it is the Dasylirion longissimum, in the ground they would tend to be much wider and more full, these are still somewhat young. Some of the Lomandra's could give a similar look, but the other suggestions given wouldn't be nearly as tall growing.