Impact of electricity price and government subsidy on digester installation
To investigate the impact on the system economic feasibility of electricity price that biogas plant owners have to pay and the government subsidy on digester installation, the electricity price was assumed to increase from 0.06 to 0.07 Euro/kWh with and without governmental subsidy. The calculated payback periods are shown in Fig. 5. The impact of electricity price could be clearly seen for the case of treated biogas. For the case with subsidy at the electricity price fixed at 0.07 Euro/kWh, the payback period for the case of treated biogas was reduced to about 5.5 years, with a trend to decrease at higher electricity prices. For both treated and untreated biogas, the governmental subsidy was the important factor determining the economics of the biogas-to-electricity systems.