啤酒薯条搭一搭，气候危机缓一缓

The technology will use CO2 captured from beer fermentation in a brewery, which is then mixed with potato waste and turned into fertiliser.

It will then be spread on UK fields to feed the following year's potato crop.

Creating fertiliser normally produces high CO2 emissions, but the technology adopted by Walkers makes fertiliser without generating CO2.

The new system will go a step further by taking away potato “cake” left after digestion - and stirring the brewery CO2 into it to make an enriched fertiliser which will help put carbon back into the soil as well as encouraging plant growth.

CCU is currently at a tiny scale, though - partly because the technologies are new, and partly because production of waste CO2 from society vastly outweighs demand for it.

CCU is a sister technology to the better-established Carbon Capture and Storage (CCS) which catches emissions from chimneys, compresses them and pumps them into underground rocks where they can’t heat the climate.

Katy Armstrong, manager of the Carbon Utilisation Centre at Sheffield University, previously told BBC News: “We need products for the way we live - and everything we do has an impact.We need to manufacture our products without increasing CO2 emissions, and if we can use waste CO2 to help make them, so much the better.”Many of the young carbon usage firms are actually carbon-negative: that means they take in more CO2 than they put out.

“There has been an increase in public awareness that we should get something done about the climate – and lot of baby steps have come together to make something significant.The key challenge for us as a business wasn’t getting down the cost – it was marketing the fertiliser. This link with PepsiCo takes care of that for us.”

“This is just the beginning of an ambitious journey, we’re incredibly excited to trial the fertiliser on a bigger scale and discover its full potential.”