Wind generated electricity requires back-up capacity of conventional power stations. This capacity is required to deliver electricity to consumers when wind supply is falling short. To have the non-wind power stations ramp up or down to compensate for the stochastic wind variations causes extra efficiency loss for such power stations. How much efficiency is lost in this way and how much extra fuel is required for this extra balancing of supply and demand is unknown. In this article we attempt to make an educated guess.
The extra fuel required for the efficiency loss must be added to the fuel required for building and installing the wind turbines and the additions to the power cable network. While these extra requirements may be too small to notice when the installed wind power is a small fraction of the total capacity, matters change when wind capacity becomes significant. Based on the German situation with 23 GW of installed wind power, we show that it becomes doubtful whether wind energy results in any fuel saving and CO2 emission reduction. What remains are the extra investments in wind energy.
Conclusions:
- It is necessary to establish on the basis of data, rather than model predictions, the level of extra fuel use caused by decreased efficiency of fossil back-up for wind power, before countries translate large investment plans in wind energy into reality.
- Wind energy easily costs more than it yields, not only in monetary terms, but also in non-sustainable energy use. Thus it will easily increase rather than decrease CO2 emission.
- Electricity companies must urgently provide the real data on extra fuel required to back up for wind-powered generators.