The initial public offering valued the new subsidiary at approximately €20 billion, raising €5 billion for for RWE which retains a 75% stake in Innogy.
Around €2 billion will be used to finance investment in Innogy's sectors.
Innogy was initially traded at €36 per share and has remained quite steady on its first day of trading.
US investment firm BlackRock is reported to have acquired €940 million worth of shares in the new company, making it the second largest shareholder with approximately 4.7%.
The new subsidiary began operations on 1 April 2016. It follows an announcement in December 2015, when RWE announced plans to separate the departments from its conventional power and energy trading business.
Initially, the parent company had planned to float just 10% of stock on the market but strong interest in the firm increased the total amount of shares issued.
Innogy is responsible for RWE's 3.5GW of renewable energy capacity, a distribution network of more than 500,000 kilometres and the utility's 23 million customers.