(Reuters) - Power producer NextEra Energy Inc NEE.N recently made a takeover approach to peer Duke Energy Corp DUK.N, the Wall Street Journal reported on Tuesday, citing people familiar with the matter. NextEra is still interested in pursuing the combination even after Duke, with a market value of more than $60 billion, rebuffed its approach, the report said on.wsj.com/30m16w1. The report, however, added there is no guarantee that NextEra would pursue a deal or whether its approach would culminate in one. NextEra, worth about $139 billion, did not immediately respond to a Reuters request for comment, while Duke said it does not comment on market rumors or speculation. Shares of Duke rose about 7% in extended trading. Earlier in the day, a NextEra unit said it had entered into definitive agreements with affiliates of Blackstone to acquire electric transmission firm GridLiance for about $660 million, including debt.