Solar thermal power generation and photovoltaic (PV) power generation are two distinct methods of harnessing energy from the sun.

While both technologies aim to convert solar energy into usable electricity, they differ in their approach and technology.

1. Solar thermal power generation

Solar thermal power generation, also known as concentrated solar power (CSP), utilizes mirrors or lenses to concentrate sunlight onto receivers. These receivers contain a heat transfer fluid or a working fluid, which is heated by the concentrated solar energy. The heated fluid then produces steam, which drives a turbine connected to a generator to produce electricity. CSP systems can incorporate various technologies such as parabolic troughs, solar power towers, and linear Fresnel reflectors.

2. Photovoltaic power generation

Photovoltaic power generation, commonly referred to as solar PV, directly converts sunlight into electricity using photovoltaic cells. PV cells are typically made from semiconductor materials, such as silicon, which can generate an electric current when exposed to sunlight. When sunlight strikes the PV cells, the photons in the sunlight transfer their energy to the electrons in the semiconductor, generating an electric current.

3. Efficiency Differences

In terms of efficiency, PV systems tend to have higher overall conversion efficiencies compared to solar thermal systems. PV cells have been improving in efficiency over the years, with some commercial panels reaching around 20% efficiency. The thermal-to-electric conversion efficiency of solar thermal systems typically ranges from 15% to 30%. However, solar thermal systems can have the advantage of storing heat in thermal storage systems, which allows for continuous power generation even when sunlight is unavailable, thereby improving overall efficiency.

4. Differences in application areas

PV systems are highly versatile and can be easily installed on various scales, ranging from small rooftop installations on homes and buildings to large-scale utility-grade solar farms. Solar thermal systems, due to their concentration and thermal storage requirements, are typically better suited for utility-scale applications with a higher power output.

5. Cost difference

The cost of solar photovoltaic technology has been decreasing rapidly over the years, making it one of the most cost-effective renewable energy options available. PV systems have lower installation and maintenance costs compared to solar thermal systems, which require complex and larger-scale infrastructure.

6. Advantageous difference

Solar thermal systems excel in large-scale electricity production and can provide dispatchable power through thermal storage. They are particularly effective in regions with high direct solar radiation. PV systems, on the other hand, are versatile, scalable, and suitable for a wide range of applications, including residential, commercial, and utility-scale installations.