The UK government is set to invest £100m to reopen a shuttered plant which produces carbon dioxide (CO2) in a contingency plan against supply disruption caused by the war in Iran. The Department for Business is expected to announce on Thursday that a site in Teesside, operated by Ensus, will restart operations after it was mothballed last year. CO2 is a key part of food and drink production and is used to stun livestock during slaughter as well as in packaging to keep food fresh, and in fizzy drinks. The plant, which manufactures bioethanol which produces CO2, was shut after the government struck a trade deal with the US which removed a tariff on American ethanol imports into the UK. The decision, first reported by the Financial Times, is believed to have been partly driven by concerns about the rising cost of energy on fertilizer companies in Europe, which also produce CO2 as a byproduct. The Department for Business and Trade and Ensus declined to comment.…