What's the Difference between "Photovoltaics" and "Solar Thermal"?

The difference between solar thermal power generation and photovoltaic power generation: Both photovoltaic and solar thermal power generation utilize solar energy to generate electricity.

Photovoltaic power generation utilizes the photovoltaic effect of semiconductor materials to directly convert sunlight into electrical energy. Its energy conversion process is a direct "light-to-electricity" conversion, offering advantages such as simple structure, rapid response, and flexible deployment.

In solar thermal power generation, light energy is not directly converted into electrical energy; instead, it is mediated by heat energy. First, reflectors reflect and focus dispersed sunlight (light energy) onto a collector, converting it into high-temperature heat energy. This heat energy is then "stored" in an insulated storage tank through a heat transfer medium such as molten salt. When the grid needs electricity, the heat energy is converted back into electrical energy through a mature thermoelectric cycle system.

Different application scenarios:

Photovoltaic power generation: Suitable for distributed generation, such as residential rooftops, commercial and industrial rooftops, and small power plants. It can also be combined with energy storage for power supply in remote areas.

Initial investment is lower, but energy storage and synchronous condensers are required to improve stability. Long-term costs are affected by the lifespan and efficiency of the energy storage system.

Concentrated solar power (CSP): Suitable for large-scale centralized power generation, often used in areas with abundant sunshine and land (such as deserts). It can complement thermal and wind power, improving grid stability.

Initial investment is high, but with technological advancements and economies of scale, the cost per kilowatt-hour gradually decreases, especially in large-scale projects where its economic advantages are significant.

The combination of photovoltaics (PV) and CSP can complement each other's strengths. Previously, on September 18th, the largest "linear Fresnel" CSP integrated energy demonstration project in China—the Three Gorges Group's Hami 1,000 kW "CSP + PV" project—achieved full-capacity grid connection, marking the official launch of a new "CSP + PV" synergistic operation model, which helps enhance the grid's capacity to accept new energy sources.