The Ukrainian grain traders union UGA asked the government on Tuesday to ensure priority supplies of electricity to grain silos to reduce potential damage to the harvest.
Russia has been targeting Ukraine's energy infrastructure with missile and drone strikes since October. The UGA said this made production processes at grain storage enterprises virtually impossible.
It said that with about 10 million tonnes of grain storage capacity lost because of the war, Ukraine "cannot afford to lose the harvest that was collected with incredible efforts".
Ukraine's 2022 grain crop could fall to around 51 million tonnes from a record 86 million tonnes in 2021 because of Russia's 24 February invasion and lower yields, the government has said.
The UGA said that power outages at one enterprise had caused grain to start heating up and the temperature inside a corn storage tank had risen to 46 degrees Celsius (114.8°Fahrenheit).
'Due to the lack of electricity, it is impossible to cool or ventilate it by moving it. Moreover, such self-heating is dangerous because it can cause an emergency situation at the enterprise,' it said.
Ukraine is among the world's largest producers and exporters of corn and wheat but exports have fallen significantly since Russia's invasion.