A recent academic study compared the solar aided power generation (SAPG) solution with that of a similar-sized stand-alone concentrating solar power (CSP) plant in the South African context. The objective was to determine the real advantages of these technologies, if any.
To determine the performance of the two types of RE technology, the study simulated a solar aided power generation (SAPG) plant at Lephalale, Limpopo province and compared it with a model of a stand-alone concentrating solar power (CSP) plant near Upington, Northern Cape.
Solar-aided Power Generation
The integration of solar thermal collectors into conventional fossil plants, or SAPG, has proven a viable solution to address the intermittency of power generation and combines the environmental benefits of solar power plants with the efficiency and reliability of fossil power plants.
The basis of SAPG technology is to use solar thermal energy to replace the bled-off steam in regenerative Rankine power cycles. The increased steam output then enables additional power generation from the turbine (solar boosting mode) or fuel consumption can be reduced (fuel saver mode).
The temperature of the heat source is one of the major defining factors of a power plant — higher temperature results in higher overall power plant efficiency. With SAPG, the heat source temperature is not limited by the solar input temperature and is therefore an effective means of utilising low or medium solar heat (250oC) for power generation. However, internationally the adoption of the technology has been slow, despite it being a viable and quick means of CO2 emission reduction.
The study was conducted on a simulated SAPG power plant at Lephalale, which was based on a generic 600-MW