Aenert news. Technological innovations
Last year, solar energy technologies continued their rapid development. Of course, this primarily applies to photovoltaic technologies. According to statistics from various sources, in 2024, approximately 2,000 TWh of electricity will be produced through photovoltaic generation, and the share of photovoltaics in the total generation volume will approach or even exceed 7%. On the one hand, this dynamic is favorable to consumers, on the other hand, it has led to overproduction of solar panels and caused an intensification of competition between manufacturers. We have repeatedly noted this in our column devoted to the analysis of financial statements of leading manufacturers of solar components.
In addition, the growth of solar energy in some regions has led to an exacerbation of problems with the stability of power grids. Also, the problems of recycling used solar panels, environmental aspects of panel manufacturing are increasingly mentioned, and agricultural producers are becoming increasingly dissatisfied due to the limited availability of space. Most of the problems that have arisen are in one way or another related to the low capacity factor of photovoltaics, which is significantly inferior in this indicator to fossil fuel-based generation sources.
Of course, fundamental natural phenomena cannot be canceled, just as it is impossible to make solar cells work at night. However, increasing the efficiency of solar cells, as well as equipping solar stations with devices for accumulating and storing energy, are tasks that are quite feasible for modern industry. The latest achievements related to records of photovoltaic technology efficiency are accumulated and systematized by the National Renewable Energy Laboratory (NREL). Below is a current diagram of confirmed research cell efficiency, posted on the NREL website.
"This plot is courtesy of the National Renewable Energy Laboratory, Golden, CO."
2024 did not see any new records in the most "research" segment of III-V Multijunction Cells. Here, the highest achievement in solar cell efficiency still belongs to the Fraunhofer Institute for Solar Energy Systems with a value of 47.6% for four-junction cells + concentrator. However, new records from last year were recorded in the more "industrial" segments, related to Perovskite cells and Thin-Film.
Perovskite is currently considered the most promising material for high-efficiency solar cells. Perovskite refers to a group of materials with a special ABX3 crystal structure, where A and B are cations and X is an anion. The first mineral with such a structure to be discovered was calcium titanate - CaTiO3, which, however, is not used to make photovoltaic cells. Perovskites containing metals and halogens are most often used for them. The significant advantages of perovskites include a relatively low excitation energy of electrons in the crystal under the influence of photons with the formation of free electrons and holes, a high rate of electron diffusion, and wide ranges of sunlight absorption.
Of greatest interest are the so-called tandem structures with layers of perovskites, or, for example, with silicon, which have the ability to absorb different colors of light (or have different band gaps). Such structures can have the highest efficiency rates. In addition, high-temperature operations and significant capital investments are not required for the production of perovskites.
However, perovskites have quite a long list of disadvantages. Among them, the first to be mentioned is the insufficient long-term and even short-term stability of the material. Reports of achieving more than 1000 hours of stability, of course, will not satisfy anyone in real practice. Loss of stability occurs due to exposure to temperature, moisture or oxygen. Another problem is the use of toxic, rare or expensive metals in perovskites, such as lead, rubidium, cesium, silver. Despite the available reports on the construction and even launch of perovskite production plants, the problem of scalability of laboratory technologies is far from solved. Finally, some stages of perovskite solar cell production have low manufacturability.
Last September, Huazhong University of Science and Technology in China reported achieving a record efficiency of 28.49% for an all-perovskite tandem solar cell. The cell operated optimally and continuously for 550 hours. The researchers were able to create a mixed Sn–Pb perovskite film with fewer defects by specially modifying the cell surface.
Silicon disk with chips. Envato Elements. AX56N8LZYB
The largest number of studies in 2024 were devoted to perovskite-silicon tandem solar cells. Leading Chinese solar panel manufacturer Longi’s September achievement of 34.6% efficiency remains unrivaled. In December 2023, the company developed a technology with 33.9% efficiency, which is “…based on a bilayer intertwined passivation strategy that combines efficient electron extraction with further suppression of nonradiative recombination.” The new work was a continuation of previous studies.
King Abdullah University of Science and Technology (KAUST) in Saudi Arabia also holds a remarkable record in this segment, with 33.2% efficiency, which was improved in June to 33.7% efficiency for a device with the same configuration.
Other researchers have been equally active. In June, China's JinkoSolar reported an efficiency of 33.84% for a tandem solar cell based on perovskite and single-crystal silicon solar cell with n-type TOPCon wafers. The work used innovations in technologies such as full-area contact passivation, perovskite interface defect passivation, and bulk defect passivation to improve the efficiency of the tandem cell. JinkoSolar's previous record was 33.24%.
For a functioning energy industry, the actual efficiency of solar modules is no less important. Chinese company, Trina Solar, has set a world record for the efficiency of a solar module - 25.44%, confirmed by the independent laboratory CalLab at Fraunhofer ISE. The record was set for a large-area crystalline silicon solar panel with front and back contact structures, and for an n-type fully passivated heterojunction (HJT) solar panel. The previous record belonged to Longi and was 25.40%. Earlier, Trina Solar achieved a world record of 27.08% efficiency for n-type fully passivated HJT cells.
House roof covered with solar panels in winter with snow on top. Envato Elements. 7KYFTNX5QV
When considering Perovskite, it is impossible not to mention other achievements of researchers aimed at expanding the use of solar cells.
A research team from the Ulsan National Institute of Science and Technology (UNIST) in South Korea has improved transparent solar cells. This promising direction has particular commercial appeal. The developed technology allows for charging many consumer devices from natural sunlight and transparent glass. UNIST's approach is based on the use of crystalline silicon and a modularization strategy. At the same time, a good efficiency of 15.8% was achieved.
Mercedes-Benz has announced the development of a unique solar paint for electric vehicles. The photovoltaic paint in the form of nanoparticles is applied directly to the body with a small consumption, but in good lighting it provides battery recharging for a trip of up to 12,000 km. Of course, if this technology is brought to commercial use, photovoltaic solar energy will receive a powerful additional vector of development.
Among the technological solutions aimed at improving the performance characteristics of solar panels, it is necessary to note the development of Polish researchers transparent silicone-epoxy coatings modified with bi- and tri-functionalized octaspherosilicates. Several variants of coatings with different combinations of chemicals made it possible to delay freezing up to 70 times compared to unmodified coatings.
The technology of vertical solar panels is increasingly used. The Norwegian company Over Easy Solar, specializing in this area, set a world record in vertical solar panels on rooftops – 248.4 kWp. This solar power station was installed on the roof of a football stadium. The vertical configuration of the panels allows to significantly reduce the occupied area, which is especially important when placing a solar station on the roofs of public buildings. In addition, double-sided vertical solar panels operate under the influence of both direct and reflected light. The total efficiency of such a design is quite comparable with the options for using expensive tracker devices. The record achievement of Norwegian specialists will obviously become a practical benchmark for further expansion of the use of this technology.
Thus, 2024 has become a year very rich in new scientific and technological achievements related to increasing the efficiency of solar energy generators and expanding their expansion in various practical applications.
By the Editorial Board
Energy News Monitoring
Solar cell efficiency 2024
