Your choices so far:
1 Process heat (150 - 1000 °C); 2 Electricity
| What is your resource? | What do you want to deliver? | What is the service the customer wants? |
| Biomass (digestible sludge) | District cooling | Comfortable indoor climate |
| Biomass (fermentable sludge) | District heating | Electricity |
| Biomass (solid) | 2 Electricity | Process cooling (< 0 °C) |
| Geothermal | Fuel: Gaseous | Process heat/steam (50 - 150 °C) |
| Sunshine | Fuel: Liquid | 1 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 – un-threatened king of the energy carriers – is often supposed to be the main demand by the customer. The reason for this is that electricity is the most flexible of all energy carriers, it can be converted into heat, it can be used for cooling and it can be used for mechanical work. Using electrical energy is also a simple thing: It can be used more or less for anything and in western and industrialised countries are the distribution grids expanded all the way out to individual houses with only few exceptions. Likewise, it is simple to control and it is clean with the end-user.
Therefore, electricity is often the preferred energy carrier whether it is the best choice from a thermodynamic standpoint or not.
Electricity shall in the first instance be used for
- Mechanical work such as needed for lawn-mowing, pumping, fanning, compressing as well as evacuating or to run escalators, lifts and alike. In the longer run, this will also include transportation.
- Illumination.
- Operation of home electronics, computers, for communication devices and such.
- To obtain cryogenic/freezing as well as extremely high temperatures.
- For electrochemical operations such as electrolytic plating and alike.
- For operations and processes where the added value from the cleanliness, the simplicity and the precision of process control can be judged to override the thermodynamic arguments against it.
Unless there are other demands, the use of electricity for modest temperatures, less than 1000 °C, is a thermodynamic overkill.
The electricity may originate from different sources, biogas or biomass-fired CHP or tri-generation plants, hydroelectricity or wind-power stations.