Biogas and combustion potential of fresh reed canary grass grown on cutover peatland

Abstract

(1) In Finland, in recent years, the combustion of dry reed canary grass (RCG, Phalaris arundinacea) grown intensively on cutover peatlands, has decreased markedly. We therefore made experiments in two areas to assess the alternative of using freshly harvested RCG grown for biogas production on cutover peatland. We measured both biogas production and combustion energy release. (2) The experiments show that the RCG biomass yields in total solids (TS) in both areas, with two cuts a year, were surprisingly small (yields of 2.7 and 4.2 Mg ha-1 [1 Mg ha-1 = 100 g m-2 ]); having biogas and combustion potentials, on the two areas, of 277–348 dm3 kg-1 VS (volatile solids) and 14.8–16.3 MJ kg-1 TS, and 11.8–21.9 MWh ha-1 in combustion. (3) Fresh RCG may produce larger biomass yields if cut several times a year, together with lower lignin proportion, and better suitability for biogas production compared with spring harvested dry RCG. (4) For cutover peatlands there are several after-use possibilities, however, with different benefits and challenges. For example, peat soil emissions may be affected during the after-use period, and this should be considered when planning the use of cutover peatlands.