Concrete is one of the most used commodities in the world, second only to water, and among the most polluting. The industry accounts for about 2.6bn tonnes of carbon dioxide each year, or about 6 per cent of global emissions. If it were a country, it would be the fourth-biggest emitter, just behind India, ahead of Russia and Japan.
Start-ups trying to produce low-carbon cement are attracting some of the most prominent tech investors, such Bill Gates’ Breakthrough Energy, Amazon’s Climate Pledge Fund, as well as venture capitalist John Doerr, of Kleiner Perkins. More than $100m in venture funding has gone to cement start-ups in the past 12 months.
The basic chemistry of cement makes it very difficult to decarbonise: the main ingredient is clinker, made from limestone heated in a kiln. As the limestone heats it releases a lot of carbon dioxide and changes its molecular structure.
This chemical reaction accounts for as much as 70 per cent of the emissions from cement making, and a remaining 30 per cent come from the energy to heat the kiln. For every 10 tonnes of cement produced, six tonnes of carbon dioxide end up in the atmosphere.
Original article:
https://www.ft.com/content/24d610a0-fb65-45bb-b747-e015e1f10c1a