Polish transmission grid operator PSE is helping its Ukrainian counterpart by supplying 300 megawatts (MW) of power between 0600GMT and 1100GMT, PSE said on Friday.
"Later, the flow will depend on the needs of their system and our ability to help," Maciej Wapinski, a PSE spokesman, said.
The European Union and Ukraine linked their electricity grids in March 2022 soon after Russia's invasion began, enabling Ukraine to receive emergency power from Europe if military attacks caused outages.
(Reporting by Yuliia Dysa and Marek Strzelecki; Editing by Hugh Lawson)
