Carbon benefits of different energy storage alternative end uses. Application to the Spanish case

Variable renewable technologies are characterized by a large degree of intermittency due to their natural variability, creating a need for exploiting a range of sources. In this context, the use of energy storage systems is often proposed. There are different ways to store and use the overproduced electricity from these technologies. This paper aims to evaluate the global warming emissions savings obtained from storing the surplus electricity from the variable renewable technologies in the Spanish market and later using it in different end use applications, both for the present day and the 2030 time horizon. First, a review of the life cycle assessments of different energy storage technologies published in the scientific literature is performed. Then, selected values from this review, adapted to the emission intensity of variable renewable electricity stored in Spain, are used to compute GHG savings from storing and using this electricity for different end uses. Results show that the highest benefits in terms of GHG emissions avoidance would be obtained in transport applications and in the power sector. However, as the electricity mix becomes decarbonized, the use of batteries behind the meter would lead to no GHG emissions avoidance. Using electricity to produce heat leads to low GHG emission avoidance benefits that will reduce over time. Benefits will improve in time for the chemical sector, as there are few alternatives to decarbonize this sector. A specific storage strategy must be formulated for each particular case.