The purpose of the analysis is to map the biomass production potentials and effects of conversion to cultivation of crops for green biorefining. The report provides concrete bids for hectares of agricultural land converted to grass for biorefining, tons of dry matter (DM) produced in biomass and the geographical location of the production of grass for biorefining for four selected coastal water catchments. Moreover, the effect in reduced nitrate emissions and greenhouse gas emissions measured as CO2-equivalents (CO2e) is calculated. Three arbitrary price levels for crop rotation grass for biorefining have been selected. Both the grassland area and the quantity of grass for biomass will naturally increase with rising grass prices. It is noteworthy that the expansion of grass used for biorefining is highest in coastal water catchment areas, where a lot of grass for roughage is already grown, which is otherwise kept unchanged. A switch to a larger proportion of grass cultivation results in a significant reduction in the climate impact from crop production due to a build-up of carbon in the soil. The greatest effect is achieved with the least possible N fertilization, i.e. by using grass-clover rather than pure grass.