FRANKFURT, April 21 (Reuters) - EEX's flagship power futures and gas products saw a year-on-year drop in trading in January-March due to the impact of the pandemic, although most environmental, feight and other power products saw growth, the European energy exchange said.

"In the European power derivatives markets (-18%) and in the gas markets (-8%), we are currently below the previous year's volume – due to the fact that we are measuring ourselves against a very strong first quarter of 2020," the Deutsche Boerse subsidiary said in remarks prepared for Reuters.

The onset of the COVID-19 pandemic in the first quarter of 2020 led to high volumes in power futures and gas trading as companies scrambled to adjust positions, a performance that was not repeated this year.

But freight markets turnover leapt up by 67%, U.S. power futures by 10%, spot power by 1%, and European environmental markets by 26% in the three months.

As continental Europe's biggest power futures exchange, and after successful forays into North America and Asia, the bourse can draw on scale and synergies between products and time zones, its newly released annual report said.

Looking ahead in 2021, EEX said it planned to build liquidity further in Japanese power futures and extend calendar year power futures with additional expiries to facilitate hedging of so-called power purchase agreements (PPAs) up to 2030.

Among a raft of new initiatives, it will also introduce handysize ship contracts in its freight segment.

It will also conduct a market consultation on possible hydrogen products, where it has gathered a working group of more than 50 organisations.

EEX platforms serve more than 750 participants.

Sales revenue in 2020 increased 5% to an all-time high of 320.1 million euros ($384.9 million), while earnings before tax grew by 3% to a record 101.1 million euros.

($1 = 0.8317 euros) (Reporting by Vera Eckert. Editing by Mark Potter)