Professor Ayhan Demirbas' area of work is mainly concerned with renewable and sustainable energy technologies. He has studied on the subjects of pyrolysis, liquefaction, gasification, and supercritical fluid extraction and gasification of biorenewable feedstocks. He has analysed the products from pyrolysis, liquefaction, gasification, and supercritical fluid extraction of biomass. Professor Demirbas has studied on the subjects of renewable transportation fuels such as biodiesel, biomethanol, bioethanol, biogas, biohydragen, gasoline and diesel fuel from fisher-trops synthesis of biofuels. He has also studied petroleum products, new products from crude oil, renewable energy resources, global renewable energy strategies and scenarios, sulfur removal from coal using alkali from biomass ashes, toxic emissions from firing and co-firing processes, global climate change, hazardous materials, persistent, organic pollutants, spectrophotometric determination of carbaryl pesticides in soil and drinking water and, creal analyses etc.