How much watt does the Gtx 970 consume minimum to maximum

Solution
The 970 has a TDP of ~145W for the reference design. This would be max load power draw for the card. Custom boards will be a little higher, maybe 25W or so. During idle, it's likely to be 20w or so. Of course, these numbers likely don't include factoring in the efficiency of your PSU, so you want to add some there. In other words, if the card can use up to 145W, it needs to pull more than that from the PSU and some is lost in the AC/DC conversion.
The 970 has a TDP of ~145W for the reference design. This would be max load power draw for the card. Custom boards will be a little higher, maybe 25W or so. During idle, it's likely to be 20w or so. Of course, these numbers likely don't include factoring in the efficiency of your PSU, so you want to add some there. In other words, if the card can use up to 145W, it needs to pull more than that from the PSU and some is lost in the AC/DC conversion.
 
Solution
Like liquid PC said , 145w is the official tdp.
The most powerful oc cards can pull 180 stock, just over 200w heavily overclocked

An average card in gaming will generally sit around 120-130w if used sensibly.

If PSU choosing is what its about then a GOOD quality 500w unit will manage absolutely fine irregardless of what CPU you're using.