Solution to spinning reserve concerns
- Regarding the discussion on windpower and spinning reserve, there are wind
systems that can handle this very well.
Like Andrew Tuckey wrote, a main issue in small grids is how to overcome
quick drops in windpower output. One way to do this is to use the rotational
energy of the wind turbine as short-term energy storage (~10 seconds with
suitable wind turbines). With a special control system, power output can
then be controlled to match the needs of the grid and reduce spinning
This concept was originally developed by Chalmers University of Technology
in Sweden. It has been demonstrated in a wind-diesel system on the island
Svenska Högarna, where 3/4 of the electricity is produced by the wind
turbine (one year average). When the wind speed exceeds 6 m/s, the diesel
can be shut down and the wind turbine controlls the frequency of the grid.
The concept has been further developed for commercial introduction in hybrid
systems by our company, ÅF, in cooperation with Chalmers. It is a low-cost
solution where no large batteries, dump loads, or special-built gensets are
To work with this concept, wind turbines must have variable speed and pitch
control. It is also of benefit with a large turbine diameter (large
inertia), in comparison to the generator rated power, and a high rotational
speed. The most suitable machines we know on the market are the PitchWind
20-30 kW wind turbines.
The control system developed by ÅF can control the wind turbine(s) and
diesel genset(s) in the local grid. It is built in a flexible way, so it can
easily be adapted for different configurations and other power plants. The
control system is based on LonWorks, recognized internationally as a
standard for open, interoperable control networks.
Using many smaller wind turbines instead of one big wind turbine can also
help reduce spinning reserve.
Wind energy consultant
P.O. Box 35
SE-16493 Kista, Sweden
Tel: +46-8-657 15 46
Fax: +46-8-657 37 01