Round trip efficiency refers to the percentage of energy recovered when electricity is stored and then retrieved. Pumped Storage Hydropower is a mature and proven technology with an efficiency range typically between 70% and 85%.
In comparison, lithium ion batteries offer much higher efficiency levels, often ranging from 85% to 95%. Because of this high efficiency, they are excellent for short term storage and stabilizing power grids quickly. However, they are generally more expensive for very large scale and long duration applications.
Hydrogen storage works quite differently. It involves using electricity to split water into hydrogen and then converting it back to electricity later. This process is less efficient, typically yielding only 30% to 40% efficiency. While the losses are higher, hydrogen is useful for seasonal storage where energy must be kept for months.
Ultimately, each technology serves a different role. PSH provides large scale capacity, lithium ion batteries offer rapid response and high efficiency, and hydrogen provides a way to store energy over much longer periods.
