The deal includes a 415MW portfolio of wind assets, including the 133MW Las Sardas project in Spain's Aragón region.
E.on's 32,000-kilometre electricity distribution network in the two countries, around 4GW of conventional energy generation, and electricity and gas supply to 650,000 customers is also part of the deal.
Despite confidentiality surrounding the sale, leaks previously suggested an offer in the range of EUR 2-2.5 billion, well below E.on's EUR 3 billion asking price.
In November, Australian investment bank Macquarie and UK investment group CVC emerged as finalists in a bid to acquire the business. Wren House is an investment vehicle set up by Kuwait's sovereign wealth fund.
Macquarie has invested through its European Infrastructure Fund 4. The same fund agreed in November to buy Italian wind developer Sorgenia Green, which has a portfolio of projects in Italy and France at various stages of development.