We explored the production cost of energy crops at abandoned agricultural land and at rest land at a regional and a global level to the year 2050 using four different land-use scenarios. The estimations were based on grid cell data on the productivity of short-rotation crops on the available land over time and assumptions regarding the capital and the labour input required to reach these productivity levels. It was concluded that large amounts of grown biomass at abandoned agricultural land and rest land, 130-270 EJ yr(-1) (about 40-70% of the present energy consumption) may be produced at costs below $2GJ(-1) by 2050 (present lower limit of cost of coal). Interesting regions because of their low production cost and significant potentials are the Former USSR, Oceania, Eastern and Western Africa and East Asia. Such low costs presume significant land productivity improvements over time and cost reductions due to learning and capital-labour substitution. An assessment of biomass fuel cost, using the primary biomass energy costs, showed that the future costs of biomass liquid fuels may be in the same order of the present diesel production costs, although this may change in the long term. Biomass-derived electricity costs are at present slightly higher than electricity baseload costs and may directly compete with estimated future production costs of fossil fuel electricity with CO2 sequestration. The present world electricity consumption of around 20PWhyr(-1) may be generated in 2050 at costs below $45 MWh(-1) in A1 and B1 and below $55 MWh(-1) in A2 and B2. At costs of $60 MWh(-1), about 18 (A2) to 53 (A1) PWh yr(-1) can be produced. (C) 2008 Elsevier Ltd. All rights reserved.