E.ON’s sales in the first quarter of 2017 fell 7% year-on-year to around €10.5 billion (£8.9bn).
The German energy firm said the drop in performance was in line with its expectations for the year, primarily due to operating in a “difficult business environment”.
The company disclosed adjusted Earnings Before Interest & Tax (EBIT) of just above €1 billion (£840m), around 34% below the year previously.
The decline was also in line with E.ON’s expectations.
The Energy Networks segment performed very well, increasing its adjusted EBIT by 11% to roughly €630 million (£531.2m).
Renewables generated adjusted EBIT of €160 million (£135m), roughly the same as the year before.
The decline in the business’ overall adjusted EBIT was primarily caused by lower earnings due to higher grid fees and higher procurement costs for power and gas in Germany and the UK.
E.ON’s first quarter adjusted net income declined by about a fifth year-on-year to roughly €525 million (£442.8m).
The company’s district heating system on a regenerated London estate has been called “not fit for purpose”.