In the past few years, environmental pollution, climate warming, and the global energy crisis have attracted much attention. On this basis, the development prospect of solar thermal power generation and photovoltaic power generation, as the main way of solar energy utilization, has also attracted the attention of the industry.
The difference between solar thermal power and photovoltaic power generation
Different power generation principles
Photovoltaic power plants use solar panels to absorb visible light from the sun to form photoelectrons and generate electricity.
Photovoltaic power generation uses a medium such as molten salt or oil to absorb the heat energy from sunlight and use a turbine to convert it into electricity.
The difficulty of grid connection is different
Photovoltaic power generation is influenced by the intensity of sunlight and brings greater pressure to the grid after going online. Its unique form of power generation makes it difficult to merge with traditional power plants.
Solar thermal power generation systems can improve their output characteristics by adding thermal storage units or by supplemental combustion or combined operation with conventional thermal power, and the output power is stable and adjustable. In terms of the difficulty of grid integration, solar thermal power generation has more advantages than conventional photovoltaic power generation. Improve the output characteristics of solar thermal power by heat storage (tank and tower type solar thermal power). This enables continuous power supply and ensures stable current, thus avoiding the problem of grid connection and peak regulation, which is difficult to solve with PV and wind power.
Different degree of pollution to the environment
Solar thermal power generation is a clean production process, which basically uses physical means for photoelectric energy conversion and poses little harm to the environment.
In contrast, photovoltaic power generation technology has the fatal weakness that solar cells have greater loss to the environment in the production process, which is a high energy consumption and high pollution production process.
Different degree of technology maturity
Conventional photovoltaic power generation technology has developed steadily in China, and the technology is relatively mature; while photovoltaic power generation, although emerging abroad early, is still in the stage of technological innovation and improvement in China.
Comparison of advantages and disadvantages of solar thermal power generation and photovoltaic power generation
Investment cost
The investment cost of solar thermal power generation is much higher than that of photovoltaic power plants. At present, the unit cost of large photovoltaic power plants built in China is about 8,000 yuan/kW, and that of solar thermal is about 22,000 yuan/kW, while that of photovoltaic power plants in the United States is 2,400-3,000 dollars/kW, and that of solar thermal is about 5,100-6,200 dollars/kW, and the cost of solar thermal is basically 2-3 times that of photovoltaic. In addition, solar thermal power plants are more sensitive to scale, and can only effectively achieve economic benefits if they are large enough. At the same time, its overall investment threshold is high, requiring nearly $500 million for a 100 MW power plant. It is because of the large investment and high risk of solar thermal power plants, even if they reach the level of grid parity, their investors are still very few compared to PV power plants, which will objectively delay their cost reduction accordingly.
Construction conditions
Photovoltaic power plants require high construction conditions, while the installation flexibility of PV is relatively large. Solar thermal power is mainly installed in places with good direct solar radiation (DNI), and desert areas are the best choice, but these places are often more remote and have weaker power demand, and need to build transmission channels for them to send power out, which will not only increase the cost, but also only enjoy the power generation side of the tariff. At the same time, because solar thermal power plants are tracking systems, they also have high requirements for local climatic conditions.
Photovoltaic power plants, on the other hand, can use both direct and diffuse light, and have a wider choice of installation areas, such as load centers, rooftops or industrial plants, and enjoy customer-side tariffs. Therefore, compared to solar thermal power plants, it is more competitive to sell at the generation side tariff.
Development Prospects of Solar Thermal Power and Photovoltaic Power
Both have development potential, but PV power plants will be larger in the near to medium term
Before 2030, as the installed cost of PV and the cost of electricity are lower than that of solar thermal power, and the PV output coincides with the peak electricity consumption and peak tariff curve during the day, the installed scale of PV will be much larger than that of solar thermal under the low penetration rate of PV. After 2030, the development of PV installation will slow down due to high penetration rate and basic ability to meet the daytime electricity demand; solar thermal will make full use of its thermal storage advantage and be able to meet the electricity peak after sunset, thus getting faster development. According to the U.S. Sunshot plan, by 2030, the cumulative installed capacity of solar energy in the U.S. will reach 330 GW, of which 302 GW of photovoltaic, 28 GW of solar thermal, photovoltaic is 11 times more than solar thermal. By 2050, solar thermal installations will reach 83GW, while PV will be 632GW, with PV declining 8 times more than solar thermal.
Non-substitute relationship, both synergistic and complementary
Both solar thermal and photovoltaic power generation face competition from traditional energy sources such as thermal power, and carry the mission of replacing fossil energy. Only better synergy and complementarity between photovoltaic and solar thermal can accomplish this mission and meet the demand for electricity. At the same time, because large wind power, photovoltaic and solar thermal power plants and other renewable energy mainly built in the desert, Gobi Beach and other areas, need long-distance transmission, but wind power, photovoltaic and other utilization hours are low, the separate long-distance transmission economy is poor, in order to improve the utilization of the transmission grid, had to be transmitted through thermal power bundling and other ways. If the solar thermal power station after maturity, it can completely replace thermal power through thermal storage, to solve the problem of low utilization of the grid, but also to solve the problem of unstable renewable energy generation.
Application areas have their own focus, the main battlefield does not overlap
The advantage of photovoltaic power generation is distributed, in the construction of load centers, combined with energy storage and other industrial development, can realize local power generation local use. At the same time, PV can also be used as a mobile power source to fully meet the needs of the consumer market, which is difficult for solar thermal power plants to reach. The advantage of photovoltaic power generation lies in its scale, which is suitable for building large photovoltaic power plants in areas with suitable conditions and then transmitting them over long distances. In these areas, large photovoltaic power plants can also be developed appropriately, and photovoltaic-thermal bundled and sent out to achieve the maximum consumption of renewable energy.
