Basic Research Needs for Solar Energy Utilization

Receiver & Power

Conversion Unit Parabolic

Dish

Concentrator

Concentrated

Sunlight

Figure 76 On-axis (parabolic dish concentrator) system configuration

that can operate efficiently at high solar fluxes and in temperature and pressure ranges
compatible with those of advanced heat engines (Bertocchi et al. 2004; Karni et al. 1997).
Enhanced radiation and convection heat transfer have been obtained by developing high-
temperature ceramic absorbers for the solar receiver (Karni et al. 1998; Fend et al. 2004).

Many estimates indicate that present technologies of the three high-temperature solar systems —
linear focus, central receiver, and on-axis concentrators — could produce electricity at a cost that
is two to three times larger than that of coal or natural gas plants. The development areas
suggested in the Priority Research Directions document should lead to the cost reductions
required to make this technology competitive with conventional electricity production within
five to ten years, assuming fossil fuels remain at present prices.

Concentrated Solar Thermochemical Processes

Solar thermochemical processes can be used to generate a primary fuel source. The concentrating
component of these systems is identical to that of concentrated solar thermal processes for power
generation, but the energy conversion is a thermochemical process converting radiation to heat to
chemical potential. These systems provide an effective means for long-term storage and
transportation of solar energy in the form of fuel and for its utilization in motor vehicles and
industrial applications. The basic concept is shown in Figure 77.