 This research paper examined the potential for using various types of waste materials as a source of energy. It looked at how much of these materials would need to be transported before they could meet the requirements set out by the European Union's Renewable Energy Directive. The study found that the maximum transport distance for achieving the required greenhouse gas emission reductions vary depending on the type of material being used. For example, it was determined that maize silage must be transported less than 30 kilometers to meet the requirements, while other materials such as animal manure or municipal solid waste could be transported up to 160 kilometers. These findings will help guide future decisions regarding the use of different types of waste materials as a source of renewable energy. This article was authored by Anna Kodba, Thomas Love Puckseck, and Nevin Duik.