Does Consult the Past only cost 1 power and no energy when hiding?

Yes, that is correct. When you use the Hidden keyword to hide Consult the Past, you ignore its printed energy cost and instead pay a cost of 1 Power (by recycling a rune).

According to Rule 737.1.b and the associated RiftJudge FAQ (6234):

• Hiding: To hide a card, you ignore both the energy and power costs printed on the card. You only pay the 1 Power cost (by recycling a rune) to put it into the Hidden state.
• Playing from Hidden: Once the card is hidden, you may play it from that state on a subsequent turn for free (ignoring its base cost).

Summary of the sequence:

1. From hand to Hidden: Pay 1 Power (recycle a rune).
2. From Hidden to battlefield (playing the card): Pay 0 energy and 0 power.