Alcohol produced with renewables could become key energy storage option – researcher

Producing synthetic alcohol with renewable power could become a significant energy storage option for the energy transition, the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) research institute has found. Combining power-to-methanol procedures with carbon captured in industrial processes would allow harnessing an energy carrier with a much higher energy density than hydrogen with respect to its volume, said HZDR researcher Stefan Fogel. “It can also be transported and stored much more easily as a liquid,” Fogel added.

Producing methanol, the simplest form of alcohol, on the basis of electrolysers using excess electricity generated by wind turbines, solar panels and other renewable power installations so far has not been scientifically explored in depth, especially with respect to its economic viability and technical adaptability into regenerative energy systems, the chemical engineer argued. Fogel modelled a “digital twin” of a power-to-methanol production facility, focusing on electrolysers that can generate hydrogen at more than 600 degrees Celsius, which are currently designed to run around the clock. The researcher instead assumed that production would be limited to times of excessive energy supply, which is more realistic given the intermittent character of renewable power production. “It turned out that such a process can very well be made more flexible,” Fogel said, adding that a power-to-methanol production facility could be operated at a competitive cost even if it is only operational during times of power production surpluses.

However, the existing fossil infrastructure that has grown over several decades still makes competitive production a challenge, Fogel added. “Building electrolysis facilities comes with massive capital expenditures,” meaning that initial investments in the technology could account for up to 70 percent of the total costs. “The actual production costs in the end are not that high,” the researcher said. Economies of scale could significantly reduce the current price gap with respect to fossil fuels, provided that a successful market launch of power-to-methanol production is achieved. According to Fogel, this could be done within the next 20 years. “By 2050, we could reach the point where power-to-methanol processes cost the same as fossil energy carriers.”  

Energy storage will become key in the next phase of the energy transition, as Germany aims to cover 80 percent of power demand with renewable sources by 2030. A traditional electricity system doesn’t require much storage because power generation can be adjusted to match demand. This changes substantially as the system uses more renewable energy, in which power generation from wind turbines and solar PV systems depends on the weather.