Someone said because Donetsk is full of energy reserves, that's why Russia wanted it badly.
And the truth is:
By 2016, the production of coal in Donetsk had dropped from 218 million metric tons to 41 million metric tons. The Donetsk Black Coal Basin in eastern Ukraine, with 90% of the nation's reserves, suffers from three connected problems: (1) mines are not profitable enough to sustain capital investment, resulting in twenty-year-old mining equipment and processes, (2) the government, taking advice from the International Monetary Fund, has discontinued $600 million annual mining subsidies, and (3) the Ukrainian government refuses to buy from mines controlled by the self-proclaimed Donetsk People's Republic and Luhansk People's Republic.
The war is not about energy recourses, the war started all because of racist hatred.
https://en.wikipedia.org/wiki/Energy_in_Ukraine