The renewable parts of that is bound to go down: As part of the push to renewables, when spinning up capacity, you get prices guaranteed for 20 years. The different to market rates is spread across the whole market ("EEG Umlage", "renewable energy law contribution").

But: that law is approaching 20 years now and so in 2021 the first installations will drop out of that subsidy scheme. Prices and guaranteed rates were dropping ever since, and so will the subsidies - with a delay of 20 years.

> there seems to be no choice for the heavy industry than to use coal

Comparing the numbers in 2000 and 2017 (https://de.wikipedia.org/wiki/Stromerzeugung#Bruttostromerze...), coal used to account for more than 50% of power generation in 2000, down to 36.6% in 2017. Even in absolute numbers to account for the rise in total power production, coal is less in 2017 than in 2000. Petrochemicals are up from 9.5% to 14.1% though.

Non-regenerative power was 436.5 TWh in 2017, down from 538.7 TWh in 2000.