Creatine phosphate
Carbs and fats can be used as long term storage and are sometimes converted from glucose.
When there is not much demand for electricity, such as during the night, the extra electricity is used to pump water back up to a storage reservoir. Then, later in the day, when electricity demand is high, the water from the storage water is also released as an extra, producing more electricity when it is needed.
When sugar is stored in the body it creates a reservoir for excess energy for whenever it will be needed again.
The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation.
When food is consumed, any excess energy is stored as fat in the adipose tissue. Adipose tissue serves as a reservoir for energy, helping to maintain energy balance in the body. This storage mechanism is crucial for survival, providing a source of energy during times of fasting or low food availability.
If you are referring to the storage of electrical energy on a large scale then, currently, the only efficient method is by hydroelectric systems which pump water from a lower reservoir to an upper reservoir during off-peak periods so that the water can be used again during on-peak periods.
Used for the production of glucose which will serve as a energy storage compound in the body
The major storage compound found in the cytoplasm is glycogen. It is a polysaccharide that serves as a reserve of glucose in cells, providing a quick source of energy when needed.
The major energy storage compound in plant seeds is starch. Starch is a complex carbohydrate made up of long chains of glucose molecules, which serves as a source of energy for the developing seedling when it germinates.
Lipids, specifically triglycerides, are considered to be a long-term storage form of energy in organisms. Lipids are highly efficient molecules for storing energy due to their high energy density and low solubility in water.
Creatine phosphate acts as a reservoir of energy for the maintenance of a steady supply of ATP in cells with high-energy demands, such as muscle cells. It can quickly donate its phosphate group to ADP to regenerate ATP during periods of high energy demand.
This compound is glycogen.