By Al Greenwood HOUSTON (ICIS)–Falling production at refineries and ethanol plants in the US has caused a shortage of carbon dioxide (CO2), leading to surcharges that can sometimes exceed the price of the gas. Ethanol plants account for 40% of US CO2 supplies, which produce 3m-3.5m tonnes/year  of the gas, according to the Renewable Fuels … Continue reading US CO2 shortage persists amid lower ethanol, refinery rates