A new leaf
Solar energy is the basis of life on Earth. All over our planet, plants photosynthesize, using their amazing and complex ability to harvest sunlight and channel it to convert carbon dioxide and water into oxygen and energy-rich carbohydrates. Our bodies get their energy from plants, so you could say that humans and other animals are solar-powered. The energy in fossil fuels is also a result of photosynthesis because fossil fuels are formed from the remains of plant and animal matter.
But what if human beings could mimic photosynthesis and use sunlight, water and carbon dioxide to produce fuels that generate electricity or power our cars and aeroplanes? It could provide a source of clean fuels for transport and also mean that we could store solar energy for use around the clock, not just when the sun is shining.
Scientists have already come up with several ways of making solar fuels in the laboratory. One is called artificial photosynthesis, where a manmade device – sometimes called an artificial leaf – carries out all the steps of capturing and channelling sunlight to produce the fuel. Another approach is using organisms, such as bacteria or algae, to produce fuels like hydrogen. The challenge is to move from laboratory prototypes to a widespread, commercially available technology that is affordable, durable and efficient. This requires tremendous research effort into everything from the discovery of new materials to the development of cheaper catalysts and more.
There are now research centres in Asia, Europe and the USA dedicated to making solar fuels a reality for the next generation. Some have even enlisted the help of young people: Professor Harry Gray, a pioneer in the field, has created a Solar Army of high-school students doing research to find the best new materials to make artificial leaves. And the US Department of Energy has created a dedicated artificial photosynthesis research hub that includes simultaneous research, engineering and product development in order to accelerate the process. No one knows when we’ll be flying and driving on solar fuels, but most researchers hope for a big breakthrough in the next 10-15 years.