Solar energy is considered one of the most promising alternatives to fossil fuels. However, in order to fully embrace this sustainable energy, we still have to overcome challenges, one of which is the long-term storage of solar energy. Storage is vital to ensure access to energy even when the sun is not shining.
A number of research papers offer hope, although they outline a new approach to storing the sun’s energy.
The liquid acts as an efficient battery
In 2018, Swedish scientists developed “solar thermal fuel,” a specialized fluid that can reportedly store energy captured by the sun for 18 years.
“A solar thermal fuel is like a rechargeable battery, but instead of electricity, you put in sunlight and get the heat running on demand,” explained Jeffrey Grossman, an engineer who works with these materials at MIT NBC News.
The fluid has been in development for more than a year by scientists at Chalmers University of Technology in Sweden.
Liquid changes are formed under sunlight
The solar thermal collector called MOST (Molecular Solar Thermal Energy Storage System) works in a circular fashion. A pump cycles the solar thermal fuel through transparent tubes. When sunlight comes in contact with fuel, the bonds between its atoms are rearranged and transformed into an energy-rich isomer. The sun’s energy is then captured between the strong chemical bonds of the isomers.
Incredibly, energy gets trapped in it even when the molecule cools to room temperature. To use the trapped energy, the liquid flows through a catalyst (also developed by the research team) creating a reaction that heats the liquid 63 ° C (113 ° F). This returns the molecule to its original shape, releasing energy in the form of heat.
“When we get to extract the energy and use it, we get an increase in heat that is greater than we dared to expect,” said research team leader Kasper Moth-Poulsen, a professor in the Department of Chemistry. and Chemical Engineering. the press release.
When an energy demand occurs, the energy-rich fluid can be used to power a building’s water heater, dishwasher, clothes dryer and more. There may also be industrial applications, including low-temperature heat used for cooking, sterilizing, bleaching, and distilling.
The liquid is pumped back to the solar thermal collector for reuse. To date, researchers have introduced fluid into this cycle more than 125 times without significant damage to its molecular structure.
Moth-Poulsen has calculated that, at its peak, fuel can store up to 250 watts of energy per 1 kg (2.2 pounds). Pound per pound, which is about twice the energy capacity of the Tesla Powerwall Batteries.
Large-scale application
By the end of 2020, an EU project led by a Chalmers team will work to develop technology prototypes for large-scale applications. The project has received 4.3 million euros from the EU and will last 3.5 years.
“With this financing, the development that now can do in the project MOST can lead to new solutions promoted by solar energy and without broadcasts for the heating in residential and industrial applications. This project is heading towards a very important and exciting stage, ”says Kasper Moth-Poulsen.
Along with this grant, news of the progress in the development of MOST appears. Researchers have used the technology in a window film to even out the temperature inside on hot days. The application of the molecule in blinds and windows has already begun through a spin-off company called Solartes AB.
Researchers believe the technology could be in commercial use within ten years.