For its wind unit, Vattenfall saw underlying profit increase from SEK 858 million (€82 million), to SEK 1.04 billion (€99.8 million) in the three-month period.
Net sales were also up from SEK 2.54 billion (€244 million) to SEK 2.96 billion (€284 million).
Vattenfall said the increase was due to the new capacity added since Q1 2017 and "positive price effects".
Despite the additional capacity, wind generation total remained flat due to "lower winds and curtailments", the firm said.
"We can gladly say that renewable energy today is not only a sustainable choice; it is also the most cost-effective new-build alternative," said Vattenfall CEO Magnus Hall.
"During the first quarter it was announced that we had the winning bid for what will be the world's first non-subsidised offshore wind farm, Hollandse Kust Zuid 1 & 2, in the Netherlands.
"This is the result of extensive work with cost reductions along the entire value chain," Hall added.