BERLIN, Aug 18 (Reuters) - German utility group RWE on Tuesday launched a share issue to finance its purchase of wind turbine maker Nordex's project development pipeline for 402.5 million euros ($480 million).

The capital increase, representing an increase of 10% in RWE's equity, will be placed with institutional investors in an accelerated bookbuilding process, RWE said in a statement issued after the market close.

Part of the proceeds will be used to finance the planned acquisition and completion of 2.7 billion gigawatts (GW) in European wind and solar projects acquired from Nordex in the deal that was made public at the end of July.

RWE, Germany's biggest utility and Europe's third-largest renewables player, wants to increase its renewables portfolio to more than 13 billion GW and invest a total of 5 billion euros by the end of 2022.

The transaction is the first major renewables deal for RWE since it took over the wind and solar activities of former subsidiary Innogy and German peer E.ON.

($1 = 0.8383 euros) (Reporting by Douglas Busvine Editing by David Holmes)