Vattenfall posted an SEK9.57 billion (€970 million) annual profit, up from a loss of SEK2.17 billion the previous year.
Its operating profit for the year grew nearly fourteen-fold, from SEK1.34 billion to SEK18.64 billion.
Sales from its wind division rose 52% year-on-year from SEK4.38 billion in 2016 to SEK 6.67billion in 2017.
This improved financial performance was "as a result of new capacity added in 2017", the company stated. Projects commissioned last year included the 288MW Sandbank offshore development in Germany's North Sea, and the 228MW Pen y Cymoedd wind farm in Wales.
Vattenfall’s wind power projects generated 7.6TWh last year, up 31% from 2016. Of the 1.8TWh increase in generation year-on-year, 1.6TWh was attributable to new capacity, Vattenfall added, with the company installing 600MW in 2017.
The company now plans to invest SEK14 billion in renewable energy "in 2018-2019", it said, with SEK13 billion of this investment being earmarked for wind power.
Vattenfall will also invest in solar energy and new businesses such as "decentralised solutions", energy storage and charging points for electric vehicles (EV), the company added.
"Vattenfall is once again a profitable company," president and CEO Magnus Hall said.
"Better conditions for conventional power generation are allowing us to increase our investments in tomorrow’s energy landscape.
"In this landscape the customer is in the centre, and Vattenfall exists to enable a climate-smarter life, entirely without fossil-based fuels."
The company said it is prepared for competitive bids in future tenders for wind power projects, as demonstrated by its participation in the Netherlands’ first non-subsidised tender for offshore wind.
It also said it was working on ways to optimise "the entire value chain" for onshore wind farms, including "procurement, development processes, construction O&M strategy (operations and maintenance), route to market and cost of capital".
Vattenfall added that that it would announce more information on projects related to potentially subsidy-free onshore wind farms "in early 2018".