Heating for residential buildings

1 the first ones will be solid fuel based on wood and coal
2 on fuel and fuel oil
3 on gas
each of them will give unity bonuses, the more advanced the better, also pollution 1 and 2 will be dirty and 3 will have fewer emissions, respectively (hydrogen without emissions).

I feel that heat should be a necessity.
Heat could be provides by:
- A solid fuel Vendor that can take Wood, Wood pulp, Coal, Biomass, and Animal feed. This service would gnerate Air pollution and Waste.
- A fluid fuel Vendor that can take Heavy oil, Medium Oil ,Light Oil, Diesel, Fuel gas, Naphta, Alkohol and Hydrogen. This Service would generate Air pollution.
-A long disance heating link that takes, Steam (Super), Steam (High), Steam (Low) and Steam (depleted)
The latter two may provide Unity, since they don't require manual fueling.