Also worth pointing out is that one of the key reasons for keeping all those "green" biomass power stations running is that they supply heating for most urban areas via "communal heating". This heat is tax-free since the heat is a "waste product", keeping the single biggest energy use sector at an artificially low price (energy use for heating is bigger than transport and consumer electricity).
It would be political suicide to start taxing the energy for heating, leading to all kinds of weirdness such as:
- Denmark _paying_ to export electricity when the power stations need to run to produce heat (because if the power plants used the electricity to provide heating, the heat would not be a waste product)!
- Big data centers cannot sell waste heat for heating, because they would need to run heat engines to raise the temperature to usable levels, again rendering the heat "not a waste product".
(TBH, The last one is so clearly stupid that a workaround in the rules is in the books)