The UK Government has introduced new controls on medium combustion plant, which includes the category of generators known as Short Term Operating Reserve (STOR). The Medium Combustion Plant Directive has been transposed into UK law as the Environmental Permitting (England and Wales) (Amendment) Regulations 2018 and requires operators to submit to a permitting regime which introduces effective controls on emissions from these plants. This means that there will be stricter (non – planning) controls on diesel generators in future and they are unlikely to be permitted in cities without effective exhaust abatement.