Researchers at ETH Zurich, a public university in Switzerland, have designed a solar reactor that makes high performance aviation fuel from only air and sunlight. The ETH Zurich team also says they plan to take their technology for making “solar kerosene,” to the industrial scale, with the ultimate goal of achieving competitive position in the aviation fuel marketplace.
BACKGROUND: SOLAR KEROSENE VS BIOFUEL
“Unlike with biofuels, whose potential is limited due to the scarcity of agricultural land,” explained John Lilliestam from the Institute for Advanced Sustainability Studies, Potsdam. “This technology enables us to meet global demand for jet fuel by using less than one percent of the world’s arid land and would not compete with the production of food or livestock feed.”
ANALYSIS: MAKING FUEL FROM AIR AND LIGHT
Led by Aldo Steinfeld, a Professor of Renewable Energy Sources at ETH Zurich, the team has been operating their mini solar refinery on the roof of the university’s Machine Laboratory for the last two years. During that time they have perfected their process of extracting CO2 and water directly from the air and then “splitting” them using only solar energy. This process, which is detailed in the journal Nature, yields a mixture of hydrogen and carbon monoxide known as syngas. When properly treated, this syngas can be processed into kerosene, methanol, and other hydrocarbons.
“This plant successfully demonstrates the technical feasibility of the entire thermochemical process for converting sunlight and ambient air into drop-in fuels,” said Steinfeld. “The system operates stably under real-world solar conditions and provides a unique platform for further research and development.”
OUTLOOK: SUSTAINABILITY AND FUTURE OF SOLAR FUELS
The research team says that the technology is now sufficiently mature for use in industrial applications. The team also adds that if the glass, steel and other materials used to manufacture the solar reactor facilities are sourced from carbon neutral suppliers, then the entire facility may reach a zero emissions status.
Given the high initial costs to produce “solar kerosene” at an industrial scale, (current projections show this process would cost from 1.20 to 2.0 Euros per liter) the team notes that solar fuels will need political support to penetrate this highly competitive marketplace.
“The European Union’s existing support instruments — emissions trading and offsetting — are not sufficient to stimulate market demand for solar fuels,” explained Lilliestam. “In view of this, we propose the adoption of a European technology-specific quota system for aviation fuel. This would require airlines to acquire a specific share of their fuel from solar sources.”
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