The effect of electric vehicle energy storage on the transition to renewable energy

Abstract

The most viable path to alleviate the Global Climate Change is the substitution of fossil fuel power plants for electricity generation with renewable energy units. This substitution requires the development of very large energy storage capacity, with the inherent thermodynamic irreversibility of the storage-recovery process. Currently, the world experiences a significant growth in the numbers of electric vehicles with large batteries. A fleet of electric vehicles is equivalent to an efficient storage capacity system to supplement the energy storage system of the electricity grid. Calculations based on the hourly demand-supply data of ERCOT, a very large electricity grid, show that a fleet of electric vehicles cannot provide all the needed capacity and the remaining capacity must be met by hydrogen. Even though the storage capacity of the batteries is close to 1–2% of the needed storage capacity of the grid, the superior round-trip storage efficiency of batteries reduces the energy dissipation associated with the storage and recovery processes by up to 38% and the total hydrogen storage capacity by up to 50%. The study also shows that anticipated improvements in the round-trip efficiencies of batteries are almost three times more effective than improvements in hydrogen storage systems.