COPENHAGEN, March 5 (Reuters) - Norsk Hydro's renewable energy unit Hydro Rein has agreed with Swedish renewables developer IOWN Energy to buy an 80% stake in a 2.4 gigawatt portfolio of planned wind power projects in Sweden and Norway, it said on Tuesday.

Hydro Rein and IOWN will enter a long-term partnership to jointly develop 23 projects in Sweden and two in Norway, which are spread across electricity price areas SE2, SE3, SE4 and NO2, Hydro said in a statement.

The two partners aim to make the first investments before 2030, Hydro said. (Reporting by Louise Breusch Rasmussen, editing by Terje Solsvik)