How does the “capacity factor” make tower systems more economical?
The capacity factor of a power plant is simply the number of hours of electricity it produces divided by the number of hours in a year. During the winter, the poor angle of the sun onto horizontal troughs lowers system performance. But because the tower’s solar field can provide adequate electricity throughout the year, towers have a higher capacity factor. Furthermore, a tower system can be designed to work at peak output levels for more hours over the course of the year, simply by adding inexpensive heliostats to an existing array of tower, receiver and power equipment. In contrast, the investment in trough plants is more evenly distributed throughout the solar field, and the raising of capacity factor is far more costly.
