Renewable based biogas upgrading

A facility for the upgrading of biogas into biomethane using renewable hydrogen has been analyzed. The biogas source is the organic matter within municipal waste. For biogas to be fed to the grid, CO2 is to be transformed. Methanation of the CO2 with renewable hydrogen is carried out. Solar and/or wind energy are the power sources for the facility. The design problem is formulated as a multiperiod optimization one for the selection of the renewable technology or combination of technologies for the production of hydrogen. Two cases of study are evaluated, regions where either wind or solar availability are high, UK and Spain respectively, and two modes of operation, continuum upgrading of the biogas or variable. Continuum upgrading is more expensive due to the large contribution of the renewable hydrogen production into the cost. Variable upgrading rate benefits from biogas storage and makes the most of the available wind and solar energy. While in the UK wind is enough to upgrade the biogas, in Spain Solar is preferred, but the large area required results in the need to use wind turbines in case continuum upgrading is required. The framework is general to analyze the type of facility that operates best in any country. (C) 2019 Elsevier Ltd. All rights reserved.