July 15, 2008
Emissions, Germany, Grid

Balancing Fluctuating Wind Energy with Fossil-Fuel Power Stations

Leonhard, W.; and Müller, K.

‘The simulation results show that even at this low penetration of wind energy, the infeed causes a hidden increase of the specific fuel consumption in remote fossil generating stations; in other words, they are now producing less electrical energy but with a higher fuel consumption and CO2- emissions per kWh. Substantial power reserves are necessary to guard against uncertainties of the wind power forecast and possible protective shut-downs of windfarms, which further strengthens the tendency towards a less efficient part-load-operation of generating units. Since the total generating capacity cannot be reduced in view of possible periods without wind, this could make investments in power stations unprofitable and endanger the future security of supply.

‘The results indicate that the frequent claims, electrical grids could be predominantly wind-supplied, are unrealistic. The simple reason is the discrepancy between the grid load and the variations of the spatial wind field; the grid load could only be modified by measures seriously affecting industrial activities (such as the temporary power cuts in the Californian energy crisis), while the wind field follows meteorological and aerodynamic laws and cannot be altered at all. By including wind power generation in the grid control, unpredictable power surges and high infeed to a lightly loaded grid could be mitigated, but this is not in the interest of the wind farm operators.

‘These effects might be reduced by spreading the “control energy” for wind over larger areas, which would require the legal obligations in Germany (EEG) for accepting this energy at high cost to be extended to other countries. It is unlikely that a European consensus can be reached, where countries with large hydro and pumped storage facilities would provide the needed control energy because they too may have to import thermally produced energy in dry years; there is already concern in the Scandinavian system regarding the fluctuations caused by the heavy windpower infeed and the local combinedheat- and-power plants in Denmark which require much control energy and might necessitate strengthening the high voltage grid; there are intervals when the grid operator is giving away surplus energy or paying dearly to cover power deficits. Europe-wide balancing of wind power from 25 000 MW offshore generation would definitely call for expanding the high voltage system, and transmission losses would also have to be taken into account.’

Electra, No. 204, October 2002

Download original document: “Balancing Fluctuating Wind Energy with Fossil-Fuel Power Stations [1]


URL to article:  https://www.wind-watch.org/documents/balancing-fluctuating-wind-energy-with-fossil-fuel-power-stations/


URLs in this post:

[1] Balancing Fluctuating Wind Energy with Fossil-Fuel Power Stations: https://docs.wind-watch.org/leonhard_balancingwindenergy.pdf