Solar energy has revolutionized the global energy landscape thanks to its sustainable alternative source characteristics. The commitment of governments and industries to solar energy as a substitute for coal to contribute to sustainable development and fight against climate change is increasingly high.
In this sense, experts in solar energy continue experimenting to take solar photovoltaic technology a step further. Currently at Bester, as specialists in renewable energies, we want to show you some advances in photovoltaic solar energy.
Floating solar panel
They are solar panels that can be installed over large bodies of water such as reservoirs, lakes, rafts and water channels for irrigation and other uses. It is an alternative for solar parks of land, simple and affordable. These floating solar panels are designed for companies that use large areas of water and use solar panels.
Another advantage of the location on the water is the increase in the efficiency of the panels; According to different studies, they could produce up to 20% more energy because water does not accumulate heat, as opposed to the earth.
However, large waves are the most obvious threat to floating solar parks installed overseas. But saltpeter and corrosion by sea salt can also cause damage to the metal structures to which it adheres and to solar panels, reducing its efficiency and its useful life.
China has, for now, the largest floating solar park in the world. It is built on a peculiar artificial lagoon, in the mining and eastern province of Anhui, with a power of up to 30 megawatts and which is capable of supplying electricity to some 15,000 homes operating at full capacity.
In 2016, the technology of manufacturing solar cells using perovskites was named one of the top 10 technologies that could transform the industry and safeguard our planet, by the World Economic Forum.
The current solar cells are based on silicon, a material difficult to find purely. So silicon dioxide is usually melted, which is abundant, but it takes a lot of energy to remove the oxygen attached to it, which translates into high greenhouse gas emissions. The production process is complicated and energy intensive. These silicon-based cells are rigid and heavy and their efficiency is limited.
The perovskite is not a single material, but a crystalline structure in which innumerable possible combinations fit. The photovoltaic properties of this material could make it possible to produce higher performance solar panels and get cheap electricity from the sun and with fewer emissions. Perovskite cells are produced at temperatures never exceeding 200 degrees, and by simpler deposition processes.
Although it has some drawbacks:
- The perovskite tends to decompose quickly, limited stability of components that are affected by the humidity.
- The perovskite contains lead, a highly toxic metal.
- The lifetime of a perovskite solar panel cannot yet compete with that of a silicon panel.
Most researchers and the market believe that perovskite will not replace silicon, at least in the medium term. "At best it can make silicon more efficient," says Henk Bolink, a researcher at the Institute of Molecular Science at the University of Valencia.
Is it possible to imagine an ink that could be sprayed as a spray on the roofs, walls or windows of our homes to generate solar energy, an ink capable of converting the energy of the sun's rays into electricity? Several companies and research groups already have materials of these characteristics, and believe that models of competitive solar ink could be launched in the market.
The photovoltaic ink emerged as a way to improve the capture of solar energy by means of semiconductor panels. The injection of photovoltaic ink increases the receptivity in the panels, thus producing a greater amount of energy.
The cells would be applied by a method that resembles the paint of a car or graphic printing, spraying in several layers. This waste is minimal and this concept would allow it to be easily adapted to mass production.
Solar perovskite ink for printable panels
As mentioned above, most commercial solar cells are made of thin sheets of very high purity crystalline silicon obtainable through a process that consumes a lot of energy, requires temperatures above 1,000 degrees Celsius and large amounts of dangerous solvents.
Dr. Hairen Tan, and his research team at the University of Toronto, presented printed solar panels capable of converting almost any surface into a power generator. The related article "Efficient and stable solution-processed planar perovskite solar cells via contact passivation” was published in the journal Science on February 17, 2017.
Perovskite (titanium trioxide and calcium) solar cells rely on a nanolayer of tiny orthorhombic crystals, each approximately 1,000 times smaller than the width of a human hair, inexpensive and sensitive to light. Perovskite preparations can be mixed in liquids to form a kind of "solar ink", usable to print on glass, plastic or other materials by a simple process of printing by injection.
Advantages and disadvantages
According to its promoters, its advantages are found in its price and its respect for the environment. On the one hand, the current solar panels are made through a very expensive process, in addition to needing significant amounts of energy. On the other hand, when the solar panels stop working, they must be recycled in an appropriate way, because, otherwise, they can become very polluting.
However, there is a "but". The energy obtained by means of traditional solar panels is still much more efficient than solar ink.