Your choices:
1 Biomass (digestible sludge); 2 Comfortable indoor climate; 3 Electricity
| What is your resource? | What do you want to deliver? | What is the service the customer wants? |
| 1 Biomass (digestible sludge) | District cooling | 2 Comfortable indoor climate |
| Biomass (fermentable sludge) | District heating | Electricity |
| Biomass (solid) | 3 Electricity | Process cooling (< 0 °C) |
| Geothermal | 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) |
For such cases when there is no need for steam at the individual farm, the use of an IC-engine and the utilisation of the cooling water for tap-water and comfort heat production is often the most viable alternative.
This is also a common type of system used in larger scales, such as wastewater treatment plants, dump sites for organic waste and alike. In these cases, the energy in the cooling water is transferred to the district heating system via a heat exchanger.
In large-scale systems, i.e. municipal scale, the total electricity efficiency may become as high as 35% while small-scale systems would scarcely end up above 25%.