The choice of energy source has a substantial impact on the climate change impact and carbon footprint of DAC. 12, 59, 60, 66-68 Non-renewable energy sources, such as petroleum and coal, emit high amounts of carbon dioxide per MWh of energy produced, while low-carbon sources like wind, hydropower, and nuclear emit much less CO2 (Fig. ). The choice of energy source becomes a large influence on the total DAC carbon footprint, illustrated in Fig. , where the carbon-intensive energy sources such as petroleum and coal have higher carbon footprints across all lifetimes. Although others have previously recognized the limited supply of large scale low-carbon electricity as an obstacle for DAC, we can see that this need becomes even more significant once we consider sorbent capacity fade in the analysis. As the sorbent degrades, the carbon footprint of DAC processes using carbon-intensive energy increases significantly over time. Using a carbon-intensive energy source with a degrading sorbent can lead to positive carbon footprints, at which point the DAC process is emitting more CO2 than it has captured.