Your choices:
1 Electricity; Electricity; 2 Wind
| 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 | 1 Electricity |
| Biomass (solid) | 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) |
| 2 Wind | Local cooling (ind. house) | Transport |
| Residual oils/fats etc | Local heating (ind. house) |
Just like in water, the energy found in moving air is basically exergy and since this is also the form of energy in electricity, wind shall be used to produce electricity and basically nothing else. The number of wind power installations is rapidly increasing and in combination with the increasing sizes of the plants installed, wind power electricity is one of the most rapidly growing sectors in the European energy system and is expected to be comparable to the hydropower production by the year 2020. Todays' installations will have an anticipated life of 20 years or more and the specific cost is successively decreasing.
At the same time as the size has increased has the versatility of the gearbox and other mechanical components improved and todays windmills exhibit significantly less maintenance costs than older designs. Also the blade design has improved during the last decades yielding turbines with lower start-wind speeds than previously.
Wind power stations come in all sizes from only few kW up to 5 MW. The smallest units are suitable for installation in the single household. However, there are a number of restrictions that may apply and before a single-home installation is done, you are advised to take good care to see which restrictions and considerations apply in your own area.
As a contrast to hydropower stations, all windpower installations suffer from the so-called "Betz limit" according to which the highest possible, theoretical efficiency is limited to about 60% (16/27 to be accurate). This limit applies also to the specific case of submerged hydropower stations but not to the other types of hydropower installations.
One main characteristic for the wind and hence also for the production capacity of wind power mills is the variability.
With the ongoing climate change and the corresponding change not only in over-all wind patterns but also in the distribution of wind speeds over the year, there will be an insecurity with respect to the future production from wind power installations.
However, more and more installation are done off-shore and such installations are less likely to experience huge changes in wind pattern than land-based.