Your choices so far:
1 Transport; 2 Fuel: liquid
| 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) | Electricity | Process cooling (< 0 °C) |
| Geothermal | Fuel: Gaseous | Process heat/steam (50 - 150 °C) |
| Sunshine | 2 Fuel: Liquid | Process heat (150 - 1000 °C) |
| Water | Fuel: Solid | Process heat (> 1000 °C) |
| Wind | Local cooling (ind. house) | 1 Transport |
| Residual oils/fats etc | Local heating (ind. house) |
If a liquid transportation fuel is desired, there will be two options, ethanol or biodiesel.
The product from fermentation is a dilute alcohol that needs be concentrated through distillation to attain fuel quality.
The main hindrances for an increase in the use of ethanol today are:
- The price for ethanol. The price reflects mainly the cost for distillation and is not likely to drop within a foreseeable future.
- The raw material for ethanol. A large fraction of today's ethanol production is based on dedicated crops (maize) grown on fertile land. An increasing worldwide awareness of the scarcity of such land has triggered a reaction to the use of ethanol as a fuel.
Due to the competition about fertile land, ethanol production should only be based on fermentable residuals or at least on non-edible biomass.
Unlike ethanol, biodiesel is an ester that can be made from several types of oils including soybean, rapeseed, sunflower, canola, corn or palm oil, animal fats (tallow), waste vegetable oils (yellow grease), and microalgal oils (lipids). Hence, the resource base includes a large number of industrial and societal waste products from restaurants, food processing industry, agriculture and other sources.
For social and ecological reasons, biodiesel should be produced only from waste-stream materials.
Both fuels are already mixed into the fossil fuels used for transportation, ethanol is mixed in gasoline and biodiesel is mixed in fossil diesel.