How food waste valorization fights climate change, Jinjin Chen, G2 (3955569)
To address climate change and reach net-zero carbon emissions by 2050, there is an urgent need to reduce the emissions from food waste landfilling. Food waste valorization to value-added products has been identified as a promising strategy with negative GHG emissions and circular economy benefit by many previous LCA studies. We develop life cycle assessment methodology to evaluate six advanced technologies to produce biogas for fossil fuel substitution and biochar for soil carbon sequestration based on both present-day and zero-carbon future grid. Our results show that both hydrothermal carbonization(HTC) to hydrochar for soil carbon sequestration and AD to produce biogas perform similarly with the current grid (around ~92kg CO2-eq), but show different result in a zero carbon future in terms of the carbon mitigation, with HTC contributing to -238 kg CO2 eq per tonne FW and AD -116 kg CO2 eq GHG. However, given the uncertainty about biochar in soil, we further determine the economic value of biogas in a zero-carbon micro-grid through HomerPro modelling of a unique case study in MN. We modelled the downtown ST, Paul and found a grid connected micro-grid with local biogas generator with local solar PV was the least-cost LCOE of $216/MWh, compared to the large grid LCOE of $220/MWh. The local combination of distributional generation performed better than with only local biogas or local solar.