London: U K private-equity firm Terra Firma has finalised its purchase of Italian PV developer Rete Rinnovabile from grid operator Terna for €641m ($912m), tying the ribbon on the largest European PV acquisition in history. First mooted late last year, the deal will see Terra Firma buy Rete Rinnovabile - Italy's biggest PV developer, with 144MW of installed capacity - using a mixture of debt and equity.