The plant microbial fuel cell (PMFC) has to be applied in wetlands to be able to generate electricity on a large scale. The objective of this PMFC application research is to clarify the differences in electricity generation between a Spartina anglica salt marsh and Phragmites australis peat soil based on experimental data and theoretical calculated potential. PMFC in salt marsh generated more than 10 times more power than the same PMFC in peat soil (18 vs 1.3 mW m(-2) plant growth area). The salt marsh reached a record power output for PMFC technology per cubic meter anode: 2.9 W m(-3). Most power is generated in the top layer of the salt marsh due to the presence of the plants and the tidal advection. The potential current generation for the salt marsh is 0.21-0.48 A m(-2) and for peat soil 0.15-0.86 A m(-2). PMFC technology is potentially able to generate a power density up to 0.52 W m(-2), which is more than what is generated for biomass combustion or anaerobic digestion using the same plant growth area. (C) 2015 Elsevier Ltd. All rights reserved.