The seasonal storage consists in the production of a synthetic fuel from the excess of electricity. This synthetic fuel will be used afterwards for producing electricity during periods of high electricity demand and low electricity production. This procedure is also known as Power-to-Fuel or Powe-to-Gas.

The seasonal storage can be necessary in scenarios with a high presence of renewable sources in the national electricity mix. Some technologies as PV or Run of river have a strong seasonal component. The seasonal storage can ease the integration of these technologies, storing their electricity production when there is no existing demand for it.

• Round-trip efficiency: 54.5% ^[1]
• Enviromental impact: The LCA analysis for this technology has not been done because of a lack of data due to the actual stage of the technology.
• Cost

The seasonal storage model is based on the liquefied methane-cycle (LM-C) presented by Easa I. Al-musleh et al. ^[1].

[1] Easa I. Al-musleh et al. (2014), Continuous power supply from a baseload renewable power plant.