The UK malting sector is responsible directly for about 300,000t CO2e emissions annually resulting from the use of primary fuels – principally gas and oil – and electricity in its operations. On a supply chain basis, even greater emissions are associated with the growing of malting barley. As with any cereal crop, farming operations include tillage and agrochemical application, of which the major contributor to greenhouse gas emissions is nitrogen fertiliser. The manufacture of nitrogen fertiliser itself consumes large amounts of energy, with consequent emissions: there are then also two sources of nitrous oxide (NO2) emission to atmosphere. The first is the leakage of NO2 from the nitric acid produced in the manufacturing process: this is now well-controlled in several fertiliser factories and is likely to be so at all factories in the near future. Replacement of some or all of the industrial nitrogen fertiliser by recycling organic materials such as compost and anaerobic digestate offers an alternative strategy for reducing the carbon footprint of malt by eliminating some emissions from fertiliser manufacture.
The second release of NO2 happens in the field, particularly under wet growing conditions. Control of this release is difficult, and there are no guidelines at present for its reduction – it comes as standard with cereal agriculture. Research has started to try to understand how growers may be able to influence these emissions for the benefit of the environment.
In addition to the embedded carbon emission in malting barley and those created by maltings’ energy use, there are emissions resulting from barley drying, transport of barley and malt, plus the relatively minor sources of office accommodation and other service activities to the central malting process. These are all worthy of some attention by energy and environmental managers, and enable everyone in a maltings team to contribute to improved environmental performance.