Dimethyl ether as a future energy vector: Economic feasibility and environmental sustainability

Power-to-X is gaining attraction due to the rapid growth of renewable electricity, aiming to limit global warming to a maximum of 2oC above the pre-industrial level. Dimethyl ether (DME) can serve as an energy vector as it has high energy density. In this work, we assessed the economic feasibility of the power-to-DME route via water electrolysis, hydrogenation of CO and H2 into methanol, and dehydration of methanol into DME. We found that under the recent condition, the power-to-DME is not economically compelling. The levelized cost of DME (LC-DME) of power-to-DME is 1695 $/ton-DME, which is 3.4 folds higher than the LC-DME of the conventional route (500 $/ton-DME). The power-to-DME can be economically attractive when the water electrolysis energy cost and electrolyzer capital cost are suppressed below 52 kWh/kg-H2 and 200 $/kW, respectively. Apart from electrolyzer performance, the electricity price of <0.03 $/kWh is required to align the LC-DME with the market price. The cradle-to-gate assessment shows that an electricity emission factor of below 19 g-CO2/kWh is necessary to bring an environmental benefit to the power-to-DME route. In addition, the electricity generation must have a capacity factor of above 70 % to avoid financial penalties due to unutilized capital.