Imagine a solar panel that generates energy at night, or a solar panel applied on a building’s roof as a coat of paint! These are not fantasies in a futuristic sci-fi movie but some of the exciting development happening around solar energy. As the world comes to the reality of the need for clean energy, human innovation is being severely tested in this field.
Southeast Asia is expected to see huge developments in both solar energy usage and innovation. As a region with fast-growing populations and economies, the need for clean energy cannot be overstated.
Thailand projects to produce 1.25 Gigawatts of solar energy by the end of 2020, while Singapore is working on floating solar farms offshore. What new developments will drive solar energy in 2021 on the path to discover full solar energy disadvantages?
Innovative Solar Energy Storage Systems
Solar energy efficiency is largely dependent on energy storage. The excess solar energy produced in the day goes to waste if there is no capacity to hold it for later use. As such, battery cells are essential components in high-performance solar energy systems.
Solar energy research is focused on improving battery storage life, just as much as it is focused on higher efficiency solar panels. The conventional lithium-ion (Li-ion) battery’s storage capacity has been stretched as long as possible, leading to the need for newer technology.
Lithium Titanate (LTO) battery is one of the emerging battery technologies. It uses lithium titanate crystals instead of carbon on the anode’s surface. This creates a larger surface area that enables faster charging and higher current release.
The Lithium-Sulfur (LiS) battery has also received attention because of its low weight, and ability to store energy for long periods. Lithium and sulfur are relatively inexpensive which adds to the cost-efficiency of a solar energy system.
Another exciting battery innovation is the Lithium-Polysulfide Flow Battery. Unlike the traditional battery, this battery uses one type of liquid- polysulfide. It has a lithium coated wall instead of a membrane, making it more compact. It can go through 2,000 cycles without charging.
Flow batteries are scalable batteries whose storage capacity can be increased when the need arises. This battery has two tanks holding liquid. These liquids pour into electrochemical cells; the electricity is stored in the resultant electrolyte instead of solid anodes.
Flow batteries come with advantages of large-scale energy storage because they can be scaled up. They are also more stable than Li-ion batteries. Flow batteries are already in use in solar farms around the world.
Futuristic Battery Designs
Battery cell research is also looking at ways of replacing lithium because of environmental conservation issues. Some of its possible replacements include more abundant silicon and sodium. The disadvantage with these materials is that they do not have the electrochemical efficiency to match lithium. Such batteries would be less energy-dense translating into shorter battery power life.
One futuristic design is the sodium-sulfur battery which has shown promise for large-scale energy storage. This battery would have molten sulfur and sodium electrodes, and a solid electrolyte. Sodium and sulfur are highly electrochemically efficient, meaning they are very good at producing electricity from a chemical reaction. But such a battery would require to operate at very high temperatures.
Scientists are also exploring a proton battery that would use water. The water would be broken down into oxygen and hydrogen. The hydrogen would then be used to power a fuel cell. This would be perhaps the cheapest battery in the world because of the abundance of water.
More Affordable Solar Energy
Southeast Asia has seen an 80% increase in electricity demand since the year 2000. This demand is expected to keep growing at the rate of 4% per year until 2040. A large share of this has been driven by households connecting to the power grid.
The International Energy Association says that one of the most significant uses of energy in Southeast Asia has been in cooling systems. In 2020 this has been slightly above 200 TWh, which is expected to grow to around 3,000 TWh by 2040.
The biggest contributor to this fast adoption of solar technology is the affordability of solar equipment. Home air conditioners, for example, have become cheaper. This is for both conventional and solar air conditioners. Innovative solar air conditioners can utilize DC power during the day, and switch to AC power at night. This increases their efficiency significantly.
Solar energy costs have also significantly reduced. The average costs for 1kWh of solar power in Southeast Asia have come down to less than $0.19/kWh.
Accelerated Solar Cell Research
The world has come a long way since the first solar cell was made in 1954. The electrical efficiency of solar cells has improved since then. This is the ability of a solar cell to convert solar energy into electricity. Today’s solar cell has an electrical efficiency of 17-19%.
Solar cells are made of silicon. Solar cells have been made more efficient by making increasingly thinner silicon cells. But this can only be done to a specific point. At this limit, a silicon solar cell will have a maximum efficiency of 30%. This is the Shockley-Queisser Limit.
Designs have been put forward to improve the efficiency of solar panels. One involves adding an extra layer to a solar cell’s back, to absorb light that was not absorbed by the first layer. This improves efficiency by 1-3%.
Another design tweak involves minimizing losses that occur at silicon and metal contact points. Adding an external layer improves efficiency by a slight 0.5-1%.
A radically improved design uses hexagonal lenses to concentrate light into the solar cell. The lenses are embedded into the protective glass layer that makes the top surface of a solar panel. This design delivers 200 times more concentrated light and improves efficiency by up to 29%.
But even with improved designs, silicon’s efficiency is still limited to 30%. This has necessitated research into solar cell technology that does not depend on silicon. New designs will combine silicon with other materials, or discard the use of silicon altogether.
One such design uses a combination of six different materials to make a multi-junction cell. This solar cell pushes efficiency by up to 47%. However, this technology is very expensive. It is currently used on space satellites.
One of the most promising technologies is perovskites. This is a photovoltaic material that is thinner than a human hair. Its width is 300 nanometers, which is almost invisible. This thinness has opened up possibilities that were unimaginable before.
Perovskites can be applied like paint to buildings, roads, or even public benches. Perovskites can also be used together with silicon to make tandem cells. This type of cell can cross the Shockley-Queisser Limit for higher efficiency.
The best thing about perovskites is that they store energy without the need for batteries. This brings down solar equipment costs significantly. Although research into Perovskites is still at an early stage, this material is being seen as a very viable alternative to silicon.
Anti-solar panels are a futuristic design that captures radiation from the ground at night to make electricity. These are photovoltaic cells working in reverse. They use the infrared light from ground radiation to generate up to 25% efficiency of modern solar panels.
The huge benefits that come with solar energy are driving fast developments in this field. In a region such as Southeast Asia, these benefits cannot be ignored. They include clean air, better environmental conservation, lowered energy costs, and a rollback of adverse climate change. In a region with fast-growing populations and economies, solar energy holds the keys to future prosperity.