This mod revisits the early game of Factorio and pushes the electrification a bit further back by extending the Burner-Stage and inserting a new stage: Steam-Stage (buildings will be powered by steam).
Efficiency mods and filters stack in terms of how much they limit pollution. For example, a tier 3 assembly machine produces 0.4/m pollution with 4 efficiency 1 modules or with 4 filter 3s, but if you mix 3 efficiency mods and 1 filter, you can get 0.31/m
