Upotrebom biomase se dobiva energija, također se na ekološko prihvatljiv način zbrinjava i iskorištava otpad i ostatak iz poljoprivrede, šumarstva i prerade drva. U Republici Hrvatskoj preporuka je da se maksimalno 30% od potencijalno dostupne biomase može koristiti u energetske svrhe, a ostalih 70% posto biomase potrebno je ostavljati na poljoprivrednim površinama zbog prirodnog obnavljanja organske tvari u tlu. Veliki problem predstavljaju invazivne strane vrste koje svojim širenjem narušavaju biološku raznolikost. Jedna od njih je i biljna vrsta pajasen [Ailanthus altissima (Mill.) Swingle], koja je jedna od najopasnijih invazivnih drvenastih biljaka kako u svijetu, tako i u Hrvatskoj. Vrlo je agresivna i prilagodljiva vrsta i pogubno djeluje na domaću floru. Cilj ovog rada je bio istražiti mogućnosti korištenja ostataka ove invazivne vrste nakon uklanjanja iz prirode mehaničkim putem, te procesom izgaranja njegove biomase ispitati njegov energetski potencijal i mogućnost korištenja biomase u energetske svrhe. Sukladno dobivenim rezultatima analiza, može se zaključiti da pajasen nudi mogućnost iskorištenja u energetske svrhe.Using biomass, energy is obtained, it is also an environmentally friendly way of managing waste and residues from agriculture, forestry and wood processing. In the Republic of Croatia, it is recommended that up to 30% of potentially available biomass can be used for energy purposes, while the remaining 70% of biomass should be left on the agricultural field due to the natural renewal of organic soil. Large problems are foreign invasive species that are rapidly spreading and damaging biodiversity. One of them is the plant species called the tree of heaven (Ailanthus altissima), which is one of the most dangerous and invasive in the world, and Croatia. It is a very aggressive and adaptable species, which has a detrimental effect on domestic flora. The goal of this research was to explore the possibilities of using remains of this invasive species after removing it from nature and combusting its biomass to examine its energy potential and the possibility of using biomass for energy purposes. According to the results of the analysis, it can be concluded that the Ailanthus altissima offers the possibility of utilization for energy purposes