3.1. Climate change
The hybrid scenario with the lowest impact on climate change, after the solar-only scenario, is wheat straw (34.2 kg CO2 eq), followed closely by wood pellets (37.5 kg CO2 eq). The biomethane scenario impact (64.1 kg CO2 eq) almost doubles the one for the straw and pellets scenarios, but it is also half of the impact of a natural gas scenario (125 kg CO2 eq). Impacts in coal and fuel oil scenarios are even higher (187 and 159 kg CO2 eq). These higher impacts in fossil fuels are mainly due to the emissions given off during fuel combustion. In the case of a biomethane scenario some methane leakage takes place due to the upgrading process (from biogas to biomethane).