'Artificial tree' could help save excess solar and wind power

A new carbon dioxide-capturing machine could help operators harness excess energy from solar and wind farms.

Researchers at the University of Twente in the Netherlands created an air capture unit, designed to capture 500g of CO₂ from ambient air per day. The artificial tree-like machine uses solid particles called sorbents, which enter an air flow and go through a low pressure drop, collecting CO₂ molecules from the air. The particles then travel to the top of a 6m column, where they flow through a heated section and release the gas to be stored.  

The team, led by Wim Brilman, said the collected gas could be useful in the production of algae, which grows “substantially” quicker when CO₂ is introduced. The photosynthetic organisms have many applications in chemistry and could also feed cattle. The air capture unit is flexible and could be used anywhere in the world, said Brilman.

Part of the carbon dioxide-harvesting unit at the University of Twente (Credit: Gijs van Ouwerkerk)

The unit, which reportedly harvests as much gas as four mature trees, could also help store energy from solar panels or wind farms as chemical energy in gas. Electricity from the sources could heat CO₂ and hydrogen in a process which creates water and methane, which in turn can heat buildings or ­power turbines.

The project, financed by the European Union, was presented at the Algae Biorefineries for Europe – Towards a Sustainable Economy congress in Brussels.

Carbon capture is also a key issue for non-renewable power sources. A recent IMechE survey found half of the public would support the construction of new coal and gas power stations if there was an efficient way to capture and store their emissions.

Jenifer Baxter, head of energy and the environment at the IMechE, called on the government to change its stance on the technology. “Government has abandoned plans to support carbon capture and storage technology in any significant way, despite studies and many pathways showing that this technology is vital to meeting climate change targets,” she said.