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Avoid fluctuations in the supply of green energy

Avoid fluctuations in the supply of green energy

Single-celled organisms capable of converting electricity to methane could help solve one of the main problems of renewables: their unreliability compared to the continuous supply provided by polluting solid fuel power plants.

Wind power is fickle, while solar power supplies dwindle at night or on cloudy days. Proposals to cope with these fluctuations in the supply of green energy include the development of better batteries or the redesign of the electricity supply network.

A surprising new idea consists of "feeding", with the surplus of energy, microorganisms that combine it with carbon dioxide to make methane; This resulting methane can be stored, to be burned when needed. The method is also sustainable, as the carbon does not come from oil or coal reserves, but is obtained from the atmosphere.

The new method relies on a microorganism studied by Bruce Logan's team at Pennsylvania State University. By living on the cathode of an electrolytic cell, the body can ingest electrons and use their energy to convert carbon dioxide into methane.

Logan's team discovered this behavior in a mixed culture of microorganisms, dominated by Methanobacterium palustre. Until now, the possibility of this behavior has been suspected, but not confirmed. For Tom Curtis, from the Institute for Research on Environment and Sustainability at the University of Newcastle, in the United Kingdom, the use of microorganisms instead of conventional catalysts is a great advance, since there are no noble metals involved in the process, this should be very cheap.

Of the energy introduced into the system in the form of electricity, 80% was eventually recovered when the methane was burned; fairly high efficiency. "Not all of the energy is recovered, but it is a problem with any form of energy storage," Curtis noted. If the CO2 used to make methane were captured from power plant flue pipes or even (using more complex methods) from the open air, the methane would become a carbon-neutral fuel.

According to Logan, commercial applications of this system could be seen in just a few years.

Source: New Scientist



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