Climate change is one of the biggest threats to humanity, so researchers are looking for renewable energy sources that are reliable, efficient, and cost-effective. Liquid sunlight, or thermal energy converted to liquid form, is one of them. And why not? Solar energy is abundant, and the sun will continue to shine for the next five billion years. As solar energy converted to liquid fuel offers so much potential, it’s high time that we start making some smart energy choices.
Turning Solar Energy to Liquid Fuel
The sun is always out there, and the solar energy available is so abundant. In fact, per year, the sun provides 23,000 terawatt-years (TWy) of energy. In 2015, the planet’s total energy consumption was 18.5 TWy. How come we are not tapping an abundant, renewable, and infinite energy source?
There are three reasons – reliability, efficiency, and cost. During night time and in places where there is not enough sunlight, solar energy is not a reliable energy source. This makes the storage of solar energy crucial. The innovations around solar energy storage are far and few, and the technology has not been fully developed. Moreover, the materials scientists need to gather energy from the sun can be costly. Photovoltaics and solar panels use platinum, copper, and cadmium. And these are expensive materials. With the high cost of installation of solar panels, adoption of the technology has been quite slow. Thankfully, a solution in the form of liquid sunlight is on the horizon.
Turning solar energy to liquid fuel is achieved by harnessing one of nature’s basic processes – photosynthesis. Just like a leaf, liquid sunlight is produced by using the sunlight to split the components of water. By mimicking the mechanism in plants, water – two parts hydrogen and one part oxygen –is processed through an intermediary system. Once split, gases such as hydrogen and carbon convert into liquid form, stored and used on-demand.
Catching Liquid Sunlight: Studies on Solar Fuel Energy
By using nature as inspiration, potentials, and innovations abound along the way. Photosynthesis is the foundation where the technology of turning solar energy into liquid fuel is built upon. Several research facilities are leading the movement towards finding sustainable energy sources through liquid sunlight.
- Dan Nocera from Harvard University is the proponent of Bionic Leaf. Through the mechanism of an artificial leaf, a built-in catalyst takes sunlight and water and produces liquid fuel that can be used immediately. The most recent prototype has an efficient and biologically-compatible catalyst. The project is showing so much promise, and they are refining iterations for commercial applications.
- ETH Zurich is working hand in hand with the European Union for the project Horizon 2020. The project aims to develop a technology that can convert sun to liquid fuel. The project kicked-off in 2016. The aim of developing a solar thermochemical technology is to convert solar energy to liquid fuel. The technology has three subsystems – sun tracking and energy gathering, production of synthetic gas, and conversion of synthetic gas to liquid form.
- UC Berkeley chemistry professor, Peidong Yang, is working on creating semiconductor materials that can capture sunlight efficiently. The gathered energy from sunlight will then be used to produce chemical reactions to extract fuel from the carbon in the atmosphere. Professor Yang, with support from UC Berkeley, is looking forward to developing a fuel source that is sustainable and environmentally-friendly.
- The Chalmers University of Technology has been developing technology that can capture the sun’s energy in a liquid form. Led by scientist, Kasper Moth-Poulsen, the study uses a liquid composed of carbon, hydrogen, and nitrogen. When exposed to the sun, this mixture locks in the sun’s energy within the chemical bonds. When it’s time to use the liquid sunlight, a catalyst can trigger the compound to rearrange its molecular structure. The conversion releases heat energy. Various applications such as water heating systems, dryers, and more may benefit from it.
There’s No Better Option than Sustainable Energy Source
The use of energy – and how and where we source it – is one of the most significant contributors to greenhouse gas emissions. This is especially true for fossil fuels. Burning fossil fuels for energy contributes to about two-thirds of the world’s greenhouse gas emissions. Extraction, transport, and processing of the fuel products have an environmental impact, too.
With the race to mitigate the impact of climate change, world leaders drafted the Paris Agreement in 2015. The goal is to “keep a global temperature rise this century well below two degrees Celsius and limit the temperature increase even further to 1.5 degrees Celsius.” By all standards, these are daunting goals. Petroleum, coal, and gas still stand as the world’s leading source of energy. There is a need to implement drastic measures to lower down our dependence on finite energy sources. Thus, the use of renewable power sources such as hydro, geothermal, and solar as the primary energy sources is of significant importance.
