Hydrogen from plastic waste
Authored by Climate LinkUP Energy Correspondent & Ambassador, Kieran Heeley
Plastic pollution is a major issue, particularly in the oceans where it is harmful to aquatic life. The issue is so severe that in the Pacific Ocean an area three times the size of France is completely covered in plastic . With more and more plastic being produced every day, much of it unrecyclable, more ways of processing this are desperately needed. In June of this year, a £21m project to produce hydrogen from waste plastic was given the green light in Scotland. The hydrogen produced then can then be used in many different applications to replace fossil fuels, such as replacing diesel engines in trucks or buses. So, how does this technology work and is this a potential solution to both plastic waste and decarbonisation?
The technology is a form of gasification, similar to that used on coal to produce town gas which was prominent before natural gas became widespread. This works by heating it to very high temperatures around 1000°C in the presence of an oxidising agent to produce a gas mixture of hydrogen, methane, carbon monoxide and carbon dioxide, while also producing some liquid and solid by-products (https://www.powerhouseenergy.co.uk/technology/ ). The hydrogen can then be separated, and the remaining gas burnt in a gas engine to provide heat for the reaction and some electricity.
The advantage of this is that it can process plastic materials that can’t be processed in existing recycling plants, preventing them from ending up in landfills or the ocean. Also, the hydrogen can replace existing diesel engines that emit dangerous particulates into the air and cause breathing difficulties in cities. However, CO2 is produced both in the reaction and subsequent burning of excess gas. Therefore, as plastic is produced from oil, the hydrogen produced cannot be considered carbon neutral. Even if the total carbon produced is lower than alternatives like incineration, the target to have net zero emissions in less than 30 years makes this technology unsuitable in the long term. Focus should instead be on reducing unwanted plastic, proper waste management and new technologies that can process a wider range of plastics without damaging the planet in other ways