Page 308 - Handbook of Energy Engineering Calculations

SOLAR-POWERED ELECTRIC-GENERATING SYSTEM
LOAD AND COST ANALYSIS

Analyze the feasibility of a solar electric generating system (SEGS) for a
power system located in a subtropical climate. Compare generating loads and
costs with conventional fossil-fuel and nuclear generating plants.

Calculation Procedure:

1. Determine when a solar electric generating system can compete with

conventional power
Solar electric generation, by definition, requires abundant sunshine. Without
such sunshine, any proposed solar electric generating plant could not meet
load demands. Hence, such a plant could not compete with conventional

fossil-fuel or nuclear plants. Therefore, solar electric generation is, at this
time, restricted to areas having high concentrations of sunshine. Such areas
are in both the subtropical and tropical regions of the world.
One successful solar electric generating system is located in the Mojave

Desert in southern California. At this writing, it has operated successfully for
some 12 years with a turbine-cycle efficiency of 37.5 percent for a solar field
2
2
of more than 2-million ft (1805.802 m ). A natural-gas backup system has a
39.5 percent efficiency. Both these levels of efficiency are amongst the
highest attainable today with any type of energy source.

2. Sketch a typical cycle arrangement
Technology developed by Luz International Ltd. uses a moderate-pressure
state-of-the-art Rankine-cycle steam-generating system using solar radiation

as its primary energy source, Fig. 1. In the Mojave Desert plant mentioned
above, a solar field comprised of parabolic-trough solar collectors, which
individually track the sun using sun sensors and microprocessors, provides
heat for the steam cycle.