First-half adjusted earnings before interest, tax, depreciation and amortisation (EBITDA) jumped 20% to 1.37 billion euros (£1.27 billion), the group said in a statement.
The rise comes just before RWE's transformation into Europe's third-largest renewable power producer, a direct result of a far-reaching asset swap with peer E.ON that involves RWE's subsidiary Innogy.
"The strong operating result gives us tailwind for the coming months, which will be one of the most exciting periods in our company's history," Chief Executive Rolf Martin Schmitz said.
RWE shares were indicated to open 1.7% higher as the second-biggest gainers among German blue-chips.
The robust performance at RWE's Supply & Trading division led the group to raise its 2019 forecast in late-July. The group now expects adjusted EBITDA to come in at between 1.4 billion euros and 1.7 billion euros, and net income of 500 million euros-800 million euros.
(Reporting by Christoph Steitz; Editing by Thomas Seythal and Sherry Jacob-Phillips)