The €25 million loss is down from the €52 million negative figure reported in H1 2017, the company said in its results.
Fortum’s "other operations" business segment also includes its newly acquired majority stake in Uniper, the former conventional power arm of German utility E.on.
For the group as a whole, operating profit in H2 grew from €219 million in 2017 to €28 million this year.
Fortum CEO Pekka Lundmark said: "Since the Uniper investment has tightened our balance sheet, our intention is to prioritise our capital expenditure and focus on cash flow optimisation, as we already announced in our first-quarter interim report.
"In the second quarter, we focused on efficiency improvements, divested our 10% minority ownership in [Norwegian hydropower unit] Hafslund Produksjon, and restructured parts of our renewables portfolio, all actions that clearly contribute to strengthening our cash flow."
In June, Fortum successfully bid to build 823MW of wind capacity in Russia in its joint venture with Rusnano, to be installed between 2019 and 2023.
It will receive a guaranteed power price of around €60-90/MWh for 15 years.
In June 2017, the Fortum-Rusnano JV was awarded the right to build 1GW of wind power in Russia by 2022. Currently, 50MW of this capacity is under construction, it stated.
"We intend to use partnerships and other forms of cooperation to create a more asset-light structure and thereby enable more investments into building new renewable capacity," Lundmark said.