Solar photovoltaic power generation is mainly based on the principle of photovoltaic effect, using solar cells to directly convert sunlight energy into electrical energy. Concentrated solar energy generation system (CPV) includes concentrators (directional mirrors), solar cells and other main parts , solar energy is “inexhaustible”, however, the current application of photovoltaic power generation systems But still limited. Most of the existing solar photovoltaic cell power generation modes use large-area flat-panel photoelectric conversion modes with fixed orientations, which have two major disadvantages: one is low photoelectric conversion rate and poor power generation capacity; Compared with conventional electric energy, it is not competitive. These limit the large-scale development of solar photovoltaic power generation systems.
Although CPV is a young technology in development, according to the analysis of professionals in early September 2009, CPV has made significant progress in the first three years. In this short period of time, the number of companies developing CPV systems has grown from a few to more than 30. The number of companies developing CPV high-efficiency cell technology is also increasing.
The use of CPV systems is ideal in some solar-rich regions, including southern Europe, the southwestern United States, Africa, Australia, parts of Latin America, and Asia. It is estimated that about 1/3 of the world’s land area can ideally use CPV, and these regions account for nearly 40% of the world’s population, and in these regions, CPV technology can exert the highest efficiency of production capacity and the lowest cost of power generation.
The challenge for CPV is that the technology is expensive to adopt. There are two key factors related to cost. The first is efficiency. The most important factor in the cost of solar energy utilization is the efficiency of the system, that is, the efficiency of the system to convert sunlight into electricity. The important thing is that its efficiency is still improving; the second factor is the manufacturing cost. From the point of view of mass manufacturing, CPV is still in the early stage of growth, and the reduction in manufacturing cost comes from the rapid increase in the number of production. And combined with automation, this will bring costs down very quickly. When efficiency improvements are combined with manufacturing cost reductions, CPVs necessarily have the potential for cost reductions.
From a zoom-in point of view, two key factors should be understood. The first is that CPV systems use very small amounts of specialty photovoltaic materials. The majority of the system is fabricated from readily available materials, including aluminum and glass. In addition, CPV also requires much lower scale-up investment than other solar technologies. This is important to rapidly build CPV capacity, as the developed CPV systems will grow from 8-50MW to GW level in the near future.
The characteristics of CPV are as follows:
(1) High temperature resistance, it is more ideal for CPV to be installed in areas with high solar energy resources. In general, silicon-based PVs and thin-film PVs experience a temperature-degrading effect when heated, resulting in a dramatic reduction in power generation as the temperature rises. In contrast, multi-bonded cells applied to CPV systems do not degrade as much as temperature increases, and the use of CPV enables the highest power generation per MW facility set up, with higher capacity directly linked to lower energy costs.
(2) Environmental sustainability, CPV uses much less PV material than traditional PV. Depending on the system, the So1Focus system can recycle more than 97% of the material (Figure 2.35). With the tracker shown in Figure 2.36, it does not directly contact the ground, and the land can be doubled.
(3) Compared with other solar technologies, CPV also has a shorter investment payback period. For reflective CPV technologies, such as the So1Focus system, the payback period is 6 months compared to 2 years for conventional PV. Another important point is that CPV power generation does not use water, and in many regions with abundant solar energy resources, water supply is lacking.
According to the research report released by Market sand market company on December 1, 2009, the average annual growth rate of the global CPV market from 2009 to 2014 will be 33.0%, and the global CPV market will be worth 266 million US dollars in 2014. Europe is expected to account for the largest share of the global CPV market, accounting for 59.3%, followed by the United States, which is expected to account for 32%.
The CPV market includes low-concentration thermal photovoltaics (LCPV), medium-concentration thermal photovoltaics (MCPV), and high-concentration thermal photovoltaics (HCPV). In all fields, HCPV will have the largest share in the global CPV market and is also expected to have the highest annual growth rate of 39.1% from 2009 to 2014. The conversion efficiency of HCPV systems reduces the demand for land and can Higher energy output at lower cost. Therefore, the cost of HCPV technology is expected to be comparable to that of other conventional energy generation, and its development rate is faster than that of other CPV technologies.