Efficiency is still pretty central in that the summer stored energy is worth at least what it would return in the winter, and often more. Methane synthesis is still pretty expensive and definitely not very efficient, so a better alternative would be to run particularly energy-hungry industries at full capacity in the summer and slow down in the winter. This wouldn’t be any more wasteful of capacity than having a major methane-producing industry that runs at full capacity in the summer and not at all the rest of the year.
If methane synthesis was substantially cheaper, then it could be useful to provide methane as a feedstock to various other chemical processes, which would also be more valuable than just burning it.
Holding energy in methane is cheap, as is holding energy in towers of dirt-cheap blocks or dams full of water. What’s expensive—for all of these processes—is the equipment to transfer the energy into stored form. On the large scale there isn’t really any known way to put a gigawatt-season of electrical energy into storage more cheaply than just building the capacity to produce an extra gigawatt in the winter. Methane doesn’t come close. Gravity storage doesn’t come close. Pumped hydro doesn’t either, and nor does hydrogen.
That’s why grid-scale energy storage systems focus on the short term: typically up to a few hours, with more speculative projects looking at a week or so.
Efficiency is still pretty central in that the summer stored energy is worth at least what it would return in the winter, and often more. Methane synthesis is still pretty expensive and definitely not very efficient, so a better alternative would be to run particularly energy-hungry industries at full capacity in the summer and slow down in the winter. This wouldn’t be any more wasteful of capacity than having a major methane-producing industry that runs at full capacity in the summer and not at all the rest of the year.
If methane synthesis was substantially cheaper, then it could be useful to provide methane as a feedstock to various other chemical processes, which would also be more valuable than just burning it.
Holding energy in methane is cheap, as is holding energy in towers of dirt-cheap blocks or dams full of water. What’s expensive—for all of these processes—is the equipment to transfer the energy into stored form. On the large scale there isn’t really any known way to put a gigawatt-season of electrical energy into storage more cheaply than just building the capacity to produce an extra gigawatt in the winter. Methane doesn’t come close. Gravity storage doesn’t come close. Pumped hydro doesn’t either, and nor does hydrogen.
That’s why grid-scale energy storage systems focus on the short term: typically up to a few hours, with more speculative projects looking at a week or so.