Multiplayer:
Though this looks better than 20 on paper, in practice it’s a less important plant on the whole. It tends to make coal expensive for the rest of the game when it comes out early, since at least one of 20/25 should show up as well and you’ll also have the 4-cap hybrids to deal with. Late in the game, it’s not so attractive when the Step 3 6-caps are coming right up. It still has value since someone will inevitably miss out on all the other big plants, but it requires a lot of care to use properly in the endgame.
As with 30, I wouldn’t touch this plant very early in the game unless it’s 5-6 player. You’ll be a long ways away from reaching the 6 cities you need, and until then you’ll keep digging yourself a bigger money hole. The restock rates in larger games make it much more palatable, along with the greater need for an early 6-cap. As you head toward the midgame, I would pay $45-50 for 31 if one of the other top coal plants is around…probably a little more if I’m desperate for an endgame plant. If both 20 & 25 are being run, this plant is potentially a death trap and you need to proceed cautiously. I would tend to stay away unless I’m at the bottom of the turn order and badly need a big plant, in which case I can stock up on coal and build. It obviously becomes worth a good bit more if coal is very cheap and you don’t see both 20 & 25 around, and this can lead to a winning strategy with one of those other coal plants (as explained in the Plant 20 article). In 5-6 player I would go $50-60 as a standard midgame price range for this, for reasons mentioned earlier.
If you get this plant early, start Step 2 if at all possible! You’ll have bad early turn order, so you want to prevent getting blocked in the future and improve coal’s restock rate. If I’m stuck with less than 7 cities in Step 1, I wouldn’t want this plant unless I know someone else will break the stall.
Using 31 well largely comes down to resource management in the endgame. With the likes of 36 & 46 lurking, and possibly even 42 on occasion, you can never feel too safe with a big coal guzzler that late. A lot of the advice from the Plant 20 article applies here – always stock extra coal whenever possible, and don’t run 31 if you have other efficient plants and wouldn’t get good value from it. This is also one of the main plants that can be strongly affected by your group’s kingmaking rules, so I’ll discuss that further here.
On BSW the regulars generally aim for 1st place and nothing else, since that site only tracks your winning percentage. Thus, the standard unwritten rule is “if you can’t win, do as little as possible to hurt anyone else’s chances of winning”. Buying out a resource from the likely winner is frowned upon even if that improves you to 2nd or 3rd place. This type of play is friendlier to the unsafe plants on the last turn, as people won’t buy out your stuff unless it’s hugely obvious you’re going to win (e.g. if you’re the only player with 18 capacity); in that case, a group of top players may split up the buyout duties to hurt themselves less. Barring that, people won’t spend a bunch of extra money just to screw you. With many other groups, on the other hand, it is considered acceptable to value 2nd place above 3rd and so on. Endgame resource buyouts are much more common in these games, so you’ll need to plan accordingly and place less value on the huge coal burners. It’s a rather fascinating example of how the metagame can change plant rankings and in-game strategy!
2-Player:
It’s less common to see 31 before Step 3 here, and this plant is badly outclassed once that comes along. Coal tends to be such a fight in 2-player that this is even less appealing than in a lot of other games. Can’t think of too many occasions when I would really want this one, besides other top coal plants being removed from the deck.
man in motion going nowhere 