My watch list  

Recycling carbon dioxide from the ocean

Floating power plants


Pexels,, CC0

In the middle of the oceans, hydrogen (H2) is to be produced from solar energy (and water), which is then converted into methanol on site using CO2 extracted from the seawater (symbolic image).

Paper, tin cans, glass - the world recycles as much as possible. So why not declare the greenhouse gas carbon dioxide (CO2) a recycling product as well? Liquid fuels based on carbon will continue to play an important role in the future - despite international efforts to reduce them. So it seems sensible to recover the CO2 exhaust from the environment and use it again.

Researchers from ETH Zurich, PSI and the Universities of Zurich, Bern and the Norwegian University of Science and Technology (NTNU), together with a team from Empa, have calculated this idea and have shown that solar methanol islands could produce enough fuel in the long term to make all CO2 emitted from transportation sources neutral - worldwide. In the middle of the oceans, hydrogen (H2) is to be produced from solar energy (and water), which is then converted into methanol on site using CO2 extracted from the seawater. To this end, the researchers analyzed in detail a scenario that still seems purely hypothetical, but already provides the basis for a possible implementation.

From sun to electricity to hydrogen to methanol

The idea is based on solar islands, i.e. floating platforms equipped with photovoltaic systems. However, since solar power cannot be stored and transported from there, a solar power plant on the sea makes no sense. Liquid methanol (CH3OH) as well as gaseous methane (CH4) can be produced from carbon dioxide and hydrogen. The researchers' idea is that the raw materials could be obtained directly from the ocean or produced there.

There are already large-scale power-to-gas plants that convert hydrogen and CO2 into fuel - including the "move" demonstration platform on the Empa campus in Dübendorf (see box). The question therefore arises: why go to sea with it? Why not, as existing plants do, extract CO2 from the air? The answer is simple: the space required for a worldwide supply of fuel would be enormous. "An area of around 170,000 km2 would be needed to produce the annual demand for global freight transport," explains Andreas Borgschulte of Empa's Advanced Analytical Technologies lab. This could best be achieved by solar power systems at sea, a previously unused area that does not belong to anyone. CO2 can also be extracted from the air at sea, but an attractive - and still obvious - alternative would be to use the roughly 125 times higher CO2 concentration of seawater for the "carbon dioxide harvest".

More possibilities for methanol

In existing plants, the CO2 extracted from the atmosphere is mostly used to produce methane, which would also be possible on the solar islands. In the course of their considerations, however, the researchers decided to produce a liquid fuel because it is easier to transport. In addition, methanol can be used not only as a fuel, but also to manufacture other chemical products, such as precursors for polymer production. The possibilities for its use (and the profits that can be achieved with it) are therefore much greater.

However, such a "methanol island" has its price: the construction of such a chemical plant on the ocean would cost around 90 million US dollars. This would consist of around 70 photovoltaic islands with a diameter of around 100 m2 and a ship with the electrolysis and synthesis plants. This would result in a total area of around 550,000 m2. But a single cluster is far from sufficient to achieve a zero balance of CO2. A total of 170,000 such islands would be needed to recycle as much CO2 as is currently emitted - a utopian goal, but one worth pursuing. "Great ideas are needed – small solutions only supply small parts of the world, but not all of it," says Borgschulte.

More about Empa
  • News

    Self healing robots that "feel pain"

    Over the next three years, researchers from the Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris) and Empa will be working together with the Dutch Polymer manufacturer SupraPolix on the next genera ... more

    New record for flexible thin-film solar cells

    Flexible solar cell with unprecedented efficiency: The Empa Laboratory for Thin Films and Photovoltaics, headed by Ayodhya N. Tiwari, has broken its own record. The researchers improved the efficiency of energy conversion in CIGS solar cells on flexible polymer substrate to 20.8%. This is 0 ... more

    Cooling with the sun

    Can you cool with waste heat? Sure. A Swiss research project involving Empa, which ended in November, demonstrated this in an impressive way. Now a large-scale EU project is starting: industrial cooling – thanks to the Spanish sun. Every now and so often heating something up is unavoidable ... more

  • Videos

    A water-based, rechargeable battery

    First step to produce a cheap aquous electrolyte for powerful rechargeable batteries: Seven grams of sodium FSI (precise name: sodium bis(fluorosulfonyl)imide) and one gram of water produce a clear saline solution with an electrochemical stability of up to 2.6 volts – twice as much as other ... more

More about Paul Scherrer Institut
More about ETH Zürich
  • News

    How light steers electrons in metals

    ETH physicists have measured how electrons in so-called transition metals get redistributed within a fraction of an optical oscillation cycle. They observed the electrons getting concentrated around the metal atoms within less than a femtosecond. This regrouping might influence important ma ... more

    A catalyst for sustainable methanol

    Scientists at ETH Zurich and oil and gas company Total have developed a new catalyst that converts CO2 and hydrogen into methanol. Offering realistic market potential, the technology paves the way for the sustainable production of fuels and chemicals. The global economy still relies on the ... more

    Targeting individual atoms

    In recent decades, NMR spectroscopy has made it possible to capture the spatial structure of chemical and biochemical molecules. Now researchers at ETH have found a way to apply this measurement principle to individual atoms. Nuclear magnetic resonance spectroscopy – NMR spectroscopy for sh ... more

  • Videos

    Oxybromination of methane over vanadium phosphate

    ETH Zurich scientists have discovered a new catalyst that allows the easy conversion of natural gas constituents into precursors for the production of fuels or complex chemicals, such as polymers or pharmaceuticals. The new catalyst is extremely stable and results in fewer unwanted by-produ ... more

More about Universität Zürich
  • News

    Researchers Observe Slowest Atom Decay Ever Measured

    The XENON1T detector is mainly used to detect dark matter particles deep underground. But a research team led by Zurich physicists, among others, has now managed to observe an extremely rare process using the detector – the decay of the Xenon-124 atom, which has an enormously long half-life ... more

    Thermodynamic Magic Enables Cooling without Energy Consumption

    Physicists at the University of Zurich have developed an amazingly simple device that allows heat to flow temporarily from a cold to a warm object without an external power supply. Intriguingly, the process initially appears to contradict the fundamental laws of physics. If you put a teapo ... more

    Water that never freezes

    Can water reach minus 263 degrees Celsius without turning into ice? Yes it can, say researchers from ETH Zurich and the University of Zurich, if it is confined in nanometre-scale lipid channels. Making ice cubes is a simple process: you take a plastic ice-cube tray like you’d find in most h ... more

More about Universität Bern
More about Norwegian University of Science and Technology
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE