Your choices:
1 Fuel: gaseous; 2 Comfortable indoor climate; 3 Biomass (solid)
| What is your resource? | What do you want to deliver? | What is the service the customer wants? |
| Biomass (digestible sludge) | District cooling | 2 Comfortable indoor climate |
| Biomass (fermentable sludge) | District heating | Electricity |
| 3 Biomass (solid) | Electricity | Process cooling (< 0 °C) |
| Geothermal | 1 Fuel: Gaseous | Process heat/steam (50 - 150 °C) |
| Sunshine | Fuel: Liquid | Process heat (150 - 1000 °C) |
| Water | Fuel: Solid | Process heat (> 1000 °C) |
| Wind | Local cooling (ind. house) | Transport |
| Residual oils/fats etc | Local heating (ind. house) |
In case the first aim with the process is to produce district heating for comfort heat, then thermal gasification immediately followed by combustion of the gas in a steam boiler for CHP or tri-generation will only make the process from fuel to energy carrier more complicated. In this case, the best route is to use direct combustion of the solid biomass in a modern steam boiler, thus reducing the process complexity to a minimum.
In the case of isolated, one-family houses, solid biomass should be used as it is in modern wood-log firing boilers or as pellets in modern pellet boilers or stoves and should not be gasified in a separate process step.