We can expect a remarkable expansion and cross-sectoral deployment of PV and wind power in the current decade. The intermittent nature of these renewables, however, will evoke challenges regarding matching energy supply and demand. Studies and strategies that aim to solve this challenge tend to neglect the flexibility potential of modern and sustainable bioenergy, despite this being the leading renewable energy resource today. We explore the current status of, and stakeholder expectations for, bioenergy flexibility, drawing on recent questionnaire data gathered in the IEA Bioenergy TCP, including some of the authors of this study, to provide a technological and deployment status review for eleven countries. We present a wide range of commercially available bioenergy technologies that can offer flexibility services. We find that sustainable biomass can be deployed for multiple services and benefits to the energy system under varying operating conditions and loads, contributing to energy security beyond the power grid. Yet, practical deployment continues to be seen as little more than a niche innovation mainly due to limited ‘landscape pressure’ and considerable challenges in translating systemic, macro-economic and societal gains into an economic profit on a business level. Considering the large variety of flexibility services, we highlight that markets and frameworks have to be designed to sufficiently reflect the qualities and limitations of the different commodities or services. Therefore, we advocate for a heterodox energy economic debate to help settle fundamental questions about the effectiveness of different market designs based on empirical approaches, quantitative modelling, and basic analytical research.