The growing production and consumption of biomethane are among the prevailing trends in European bioenergy. Biomethane is a close analogue of natural gas, so it can be used for the production of heat and power as well as consumed as a motor fuel and raw material for the chemical industry. Biomethane production is in line with the concept of a circular economy, since it converts agricultural by-products and residues, as well as industrial and household wastes, into energy, at the same time ensuring the recycling of nutrients back to agricultural land. The application of biomethane to replace fossil fuels requires minimal additional resources and time to develop new infrastructure or adjust the existing one. This makes biomethane a key player in the transition towards a climate-neutral economy. Expanding production of biomethane requires new sources of sustainable feedstock. Sequential cropping offers an opportunity to produce sustainable biomass for energy, reducing greenhouse gas (GHG) emissions and avoiding competition with food production. Available studies show that the potential of biomethane production from intermediate crops in Europe is about 45 billion m3/y. In Ukraine, up to now, intermediate crops have been grown in limited areas for use as green manure or for feed production. Spreading the area under such crops and integrating the biomass into biomethane value chains, with nutrients returned to the soil through digestate, is a new perspective for sustainable bioenergy and agriculture. The assessed potential for biomethane production from intermediate crops in Ukraine is more than 9 billion m3/y. A feasibility study of biomethane production from such crops shows sufficient attractiveness of the relevant project for investments, with a discounted payback period of 7.8 years and a 20% internal return rate. The averaged emissions during the biomethane life cycle could be negative, provided the carbon dioxide obtained from biogas upgrading is usefully utilised to replace carbon dioxide obtained from fossil fuels. The GHG emissions for biomethane from intermediate crops might reach -13 gCO2eq/MJ when intermediate crops are co-digested with manure, and 25% of the total biomethane comes from this feedstock.