Fixing nitrogen fixing


Source: © Royal Society of Chemistry

Green ammonia promises a more sustainable future. Jamie Durrani talks to the researchers aiming to revolutionise the production of crucial fertiliser

In the early 20th century the newly developed Haber–Bosch process transformed food production. Reliable access to ammonia-based fertilisers was a huge boost to agriculture and helped to sustain the planet’s rapidly growing population. Today, giant Haber–Bosch reactors produce around 180 million tonnes of ammonia each year, using up more than 1% of the total energy produced world-wide. The process is also intertwined with fossil fuel extraction – the hydrogen feedstocks are made by steam reformation of coal and natural gas – and is directly responsible for 450 million tonnes of carbon dioxide emissions annually.

With the urgent need to cut society’s carbon emissions, Haber–Bosch is long overdue a makeover. Many researchers now believe that sustainably produced ‘green’ ammonia would not only reduce the environmental impact of fertilisers, but could also be used as a clean energy carrier.