Bioenergy, in solid, liquid and gaseous form, has the potential to reduce greenhouse gas emissions and contribute to climate change mitigation. Bioenergy is increasingly becoming cost competitive. Electricity generated from bioenergy is amongst the cheapest of renewable energy technologies. At the same time bioenergy can reduce import dependencies and can contribute to energy security, such as when biogas substitutes natural gas. However bioenergy also involves a range of challenges, mostly related to limited land availability and sustainability challenges. Third generation biofuels may have the potential to reduce emissions while not requiring additional land. Waste products from the agricultural and waste treatment sectors can also be used as feedstocks for bioenergy production. Finally for some technologies more R&D is needed, as well as stronger policy and investment support to foster the scaling-up of modern bioenergy across the globe.