Wood to Coal Recipe - implications for progression

[4wry]

Pretty much title. It would be nice to have a recipe that converts wood harvested on Nauvis to coal, giving players more options to use/recycle/dispose of wood. Coal can already be produced infinitely on asteroids from carbon/sulfur using coal synthesis, and Gleba has a recipe for Spoilage to carbon using spoilage, which could be converted to coal using coal synthesis.

The recipe for spoilage to carbon (using a Biolab) is: 6 spoilage + 12/s = 1 carbon.

Notably spoilage has a significantly lower energy value (250kJ, compared to carbon's 2MJ, and coals 4MJ), so there is a small gain of energy value since 6x250kJ is only 1.5MJ).

The notion is to create a recipe for Nauvis that can turn wood into coal, in an equivalent 'burnt wood' recipe. The suggestion would be to allow this directly from wood, possibly with an added component such as steam, rather than introducing carbon (e.g. 2 wood (2x2MJ) to 1 carbon (2MJ)) an an intermediate (which is a space/vulcanus/gleba item). Instead,

The suggestion would be to enable coal synthesis using e.g. a 'wood processing' recipe, e.g. in chemical lab.
The coal synthesis recipe is:
1 sulfur + 5 carbon + 10 water +2s = 1 coal

The wood processing recipe could be:
10 crude oil + 2 wood + 20 steam +5s = 1 coal, or something like that.

Ratios could be balanced (e.g. to use less wood, more steam etc.).
The idea is to have this recipe available only after the early game, e.g. when having access to oil and chemical labs, but avoid prematurely introducing carbon at this point. Note that the above recipe entails an initial small loss in total burn value due to the oil used (2 wood x 2MJ = 4MJ + Oil, compared to 4MJ for coal - this could be balanced based on the recipe). Coal is not an intermediate, so productivity modules cannot be used. Some energy value could be re-gained when feeding the coal to liquefaction in the later game (another progression).

However, this will give players some options early on to convert wood to coal, which could be used for e.g. trains (fewer re-stocks and higher speed), plastic, liquefaction, solid fuel etc. rather than only being burnt. The recipe will only be sustainable and automated after having been to Gleba, which will allow to automate tree planting (another progression step). Aquilo could enable this recipe in cryogenic labs (another progression step).

Very late game, this would also be a potential source for quality coal, via quality modules. The recipe can be adjusted accordingly based on more intricate testing and calculations in order to balance this aspect. Coal doesn't recycle to wood, so there is litte risk of this being unbalanced compared to existing approaches in that regard.