PRIMARY aims to develop and pilot local solutions for the production of food, feed, bio-based materials, bioenergy, and fertilizers by valorizing agricultural biomass feedstocks, including grass, greenhouse and cotton by-products, and olive tree pruning that are currently underutilized and exist in substantial amounts in Europe. The project focuses on North-East Europe (Finland) and South-East Europe (Greece), providing business models and demonstrations in rural areas where pilot and demo plants are rare. PRIMARY works with primary producers and local actors, and pilots six process concepts: 1) separation of protein and fibre rich fractions from grass to produce food/feed and biobased materials, respectively; 2) submerged and 3) solid-state fermentation processes to upcycle the feedstocks to protein rich food and feed ingredients; 4) fibre forming technology to enable production of packaging and construction materials; 5) pelletizing process to solid biofuel for gasification to bioenergy from olive-tree pruning and cotton byproducts; 6) pyrolysis of cotton and olive byproducts to biochar for fertilizer and material applications. The solutions piloted in the project are selected based on cascading use of the feedstocks to find the highest possible value, considering the regional conditions. Sustainability of the new value chains is broadly assessed. To maximise project outcomes and impact, other partners and regions are engaged through an open innovation call to promote the ecosystem for valorizing agricultural biomass, and to show replicability of the project solutions. PRIMARY outcomes, including new processes, products and service concepts, will be communicated via various channels, including a stakeholder platform, to ensure wide exploitation of the solutions. A multi-actor approach is used in the development of processes and replicable business models, and for delivering guidance to farmers and SMEs, and advice to policymakers at national and EU level.