A new method for the methanation of hydrogen and carbon dioxide is presented. In a novel anaerobic trickle-bed reactor, biochemical catalyzed methanation at mesophilic temperatures and ambient pressure can be realized. The conversion of gaseous substrates by immobilized hydrogenotrophic methanogens is a unique feature of this reactor type. The already patented reactor produces biogas which has a very high quality (c(CH4) = 97.9 vol%). Therefore, the storage of biogas in the existing natural gas grid is possible without extensive purification. The specific methane production was measured with P = 1.17 Nm(CH4)(3)/(m(R)(3) d). It is conceivable to realize the process at sites that generate solar or wind energy and sites subject to the conditions for hydrogen electrolysis (or other methods of hydrogen production). The combination with conventional biogas plants under hydrogen addition to methane enrichment is possible as well. The process enables the coupling of various renewable energy sources. (C) 2013 Elsevier Ltd. All rights reserved.