Your choices:
1 Electricity; 2 Comfortable indoor climate; 3 Sunshine
| 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 |
| Biomass (solid) | 1 Electricity | Process cooling (< 0 °C) |
| Geothermal | Fuel: Gaseous | Process heat/steam (50 - 150 °C) |
| 3 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) |
Electricity is the king of energy carriers and should generally not be used for low-exergy purposes such as indoor climate control, unless there are special circumstances.
In case the electricity is produced from solar cells placed e.g. on the roof of a building, then the electricity produced will be limited and it will be intermittent. There will be no reason, in a case like this, to make any major alterations to the internal energy system in the building because of such a marginal and un-reliable source of electricity as a solar cell panel.
Hence, the electricity produced should be transformed into 230 V, single-phase AC and just "dumped" into the internal electricity system of the building. So in this case, the locally produced electricity will provide a saving for the house owner and it will save electricity from the grid – even though the electricity in itself may not be used in the thermodynamically best way.