Carbon capture: recovering the riches that go up in smoke
With UN climate talks taking place in New York in September, the issues of climate change and energy security were thrust right to the forefront of global concern. World leaders acknowledged that drastic and immediate changes are needed to cut back on the quantity of carbon dioxide, the most significant greenhouse gas, we emit into the atmosphere.
One of the keys to achieving this will be developing less carbon-intensive ways to produce energy, including electricity and fuel for transport. Using alternative energy sources to fossil fuels, including nuclear power and renewables such as wind and solar power, will naturally mean reduced emissions.
However, scientists and engineers are also looking at ways of not only reducing the CO2 we emit, but directly ‘pulling’ emissions back out of the air. What’s more, they are able to use these emissions to create useful products, which we use on a daily basis. The method is known as carbon capture and utilisation (CCU).
The idea is already being developed widely, by both researchers and businesses. One example is Liquid Light, a spin-out project from Princeton University. By selecting the right catalysts, the company has been able to convert atmospheric carbon dioxide into ethylene glycol, a chemical used in anti-freeze, polyester bottles and fibres.
In May 2014, the German chemical company Bayer MaterialScience announced a plan to begin producing polyols from carbon dioxide gas. Polyols are a type of alcohol which are a precursor for making polyurethane foam, commonly used to make mattresses. This is by no means a small operation – the company plans to produce over 5,000 tonnes of the foam annually by 2016!
Another interesting form of carbon capture involves algae and other green freshwater plants. Gas high in CO2, such as flue gas from industrial chimneys, is fed over a large culture of algae. The algae combine this with water and energy from sunlight to produce a range of organic compounds. In large quantities, these compounds form a great biomass fuel, and can be burned to generate electricity.
The range of potential products which can be forged from atmospheric CO2 is impressive. From synthetic diesel oil to lithium ion batteries, jet fuel to industrial solvents, construction materials to fizzy drinks. And all of them recycling from the carbon cycle, rather than adding to it.
However, the impact that CCU will have on the global fight against climate change is debatable. Some believe that the technology is practical, and scalable enough to have a major impact. Others argue that the CO2 savings are too small, and that because an input of energy is required (most likely from a fossil fuel source) the overall carbon saving is reduced. Few would argue however, that converting a useless and climate change-driving gas into a useful end product isn’t a step in the right direction.
Image: ‘Sunset and Smoke’ from Wikimedia Commons under creative commons license