from the Market Data API are provided in 15-minute intervals. However, additional endpoints have been created to offer new price and system price indices in 60-minute and 30-minute intervals for users who need them.
Similarly, a new indices page is avaiable on the public Nord Pool market data page and in the Data Portal (under https://data.nordpoolgroup.com/auction/day-ahead/) where these other granularities will be published.