THIS ARTICLE IS republished from The conversation under a Creative Commons License.
The sight of rooftop solar panels and large energy farms has become commonplace in many regions of the world. Even in the gray and rainy United Kingdom, solar energy is becoming a major player in electricity generation.
This rise in solar energy is driven by two key developments. First, scientists, engineers and industry professionals are learning how to make billions of solar panels. Each manufacturing step is meticulously optimized to produce them at a very economical price. The second and most significant is the relentless increase in the panels’ energy conversion efficiency, a measure of how much sunlight can be transformed into electricity.
The greater the solar panel efficiencycheaper is electricity. This might make one wonder: How efficient can we expect solar energy to be? And will it affect our energy bills?
Commercially available solar panels today convert 20 to 22 percent of sunlight into electrical energy. However, new research published in Nature has shown that future solar panels could achieve efficiencies of up to 34 percent by exploiting a new technology called tandem solar cells. Research demonstrates record energy conversion efficiency for tandem solar cells.
What are tandem solar cells?
Traditional solar cells are made using a single material to absorb sunlight. Today, almost all solar panels are made of silicon, the same material found at the core of microchips. While silicon is a mature and reliable material, its efficiency is limited to about 29 percent.
To overcome this limit, scientists have turned to tandem solar cells, which stack two solar materials on top of each other to capture more energy from the sun.
In the new Nature paper, a team of researchers from energy giant LONGi has reported on a new tandem solar cell that combines silicon and perovskite materials. Thanks to its better capture of sunlight, the new perovskite-silicon tandem has achieved a world record efficiency of 33.89 percent.
Perovskite solar materials, which were discovered less than two decades agoThey have become the ideal complement to the already established silicon technology. The secret is in your light absorption tunability. Perovskite materials can capture high-energy blue light more efficiently than silicon.
In this way, energy losses are avoided and the total efficiency of the tandem is increased. Other materials, So-called III-V semiconductors have also been used in tandem cells and have achieved higher efficiencies. The problem is that they are difficult to produce and expensive, so small solar cells can only be made in combination with focused light.
The scientific community is devoting enormous efforts to perovskite solar cells. They have maintained a phenomenal pace of development with efficiencies (for a single cell in the laboratory) increasing from 14 percent to 26 percent in just 10 years. These advances enabled their integration into ultra-high-efficiency tandem solar cells, demonstrating a path to scale photovoltaic technology to the trillions of watts the world needs to decarbonize our energy production.
The cost of solar electricity
The new record-breaking tandem cells can capture an additional 60 percent of solar energy. This means that fewer panels are needed to produce the same energy, reducing installation costs and land (or roof area) required for solar farms.
It also means that power plant operators will generate solar energy at higher profits. However, due to the way in which Electricity prices are set in the United Kingdom.Consumers may never notice a difference in their electricity bills. The real difference arises when considering rooftop solar installations, where the area is limited and space must be exploited effectively.
