What if sunlight could turn waste into the fuels and chemicals we rely on every day? In our next Speaker Spotlight with Professor Erwin Reisner, ahead of Beyond photovoltaics: Unlocking the photon economy with solar chemical technologies on 21 March 2026, we explore bold new solar-powered approaches to transforming carbon dioxide, biomass and plastic waste into valuable resources, and how these breakthrough technologies could help drive a circular, net-zero future.
Erwin Reisner is Professor of Energy and Sustainability at the University of Cambridge, where he develops solar-powered technologies that turn carbon dioxide and waste into sustainable fuels and chemicals. His work on artificial photosynthesis and solar reforming has led to prototype solar-fuel devices and the spin-out company Protonera to commercialise the technology.
“The photon economy is the future – we just don’t know how it will look like yet and we therefore work on scenarios and development of this technology in Cambridge.”
Can sunlight turn our waste into fuel?
Yes. Sunlight can be used as an abundant and free energy form to make fuel from waste. Think of a solar panel doing chemistry – instead of producing electricity, we feed the panel with waste to make useful products. That’s similar to what nature is doing in photosynthesis.
How close are we to a carbon-zero chemical industry?
This is probably the most difficult part of the energy transition. We still need to establish many of the scientific principles and then develop them into technologies at scale. It’s an extremely tough but important challenge – that’s why we are working on this in Cambridge.
Which solar chemistry breakthrough excites you most right now?
Ten years ago, solar chemistry focused solely on the production of simple fuels such as hydrogen. Today, the possibilities seem almost endless and range from the development of liquid fuels to chemical building blocks to replace fossil fuels in the chemical industry to making drug molecules for pharma – all through circular chemistry powered by sunlight. This has also created real commercial opportunities, and the first start-ups are already popping up.
Could plastic and CO₂ become tomorrow’s energy source?
Both will become important resources and have real value in the next decades. Both are rich in carbon to make chemical products, but plastics has the advantage over CO2 that is contains carbon in a highly concentrated form and that it is also a very energy-rich feedstock. It really is an untapped resource that we need to learn to utilise.
What advantages have your solar devices compared to photovoltaics?
Half of the solar energy is heat, known as infrared light, and this goes to waste in photovoltaics. In our solar devices, we can also use heat and thus in principle use the entire solar spectrum. It is therefore in principle possible that our solar devices are more efficient than photovoltaics and produce products of much higher value. We hope to demonstrate this in the next couple of years.
If the public remembers one thing, what should it be about the photon economy?
Solar energy is vastly abundant and its production already very cheap – it is therefore growing quickly and will become the dominant energy form in the next few decades. It will therefore dominate the chemical industry and our economy by 2050. The take-home message is: The photon economy is the future – we just don’t know how it will look like yet and we therefore work on scenarios and development of this technology in Cambridge.
“It’s an extremely tough but important challenge – that’s why we are working on this in Cambridge.”
source: www.cam.ac.uk