10 Must-Knows About Energy Storage Technologies

Energy storage is crucial for stabilising power grids, integrating renewable energy, and improving energy efficiency across industries. Here are ten key facts you should know:

1. Energy Storage Ensures Reliability for Renewable Energy

In essence, energy storage solutions tackle the intermittency of renewable sources of power. Solar and wind power availability relies on weather conditions and the time of day, resulting in the production of power when there is less demand for it, and this is when storage solutions can offer this power. The International Energy Agency states that the required scale of grid-based storage solutions will need to increase by a factor of more than six times in 2030 in order for the targets for renewable power sources to be achieved.

2. Lithium-Ion Batteries Currently Dominate the Market

Among all the storage solutions available today, Lithium-ion batteries are the most used. This is due to the high energy density contained in these cells, as they offer more than 90% round-trip efficiency, and the cost of these batteries has decreased by nearly 90% from where it started in 2010. Currently, Lithium-ion batteries constitute more than 85% of newly installed battery-based storage.

3. Flow Batteries Make Long-Duration Energy Storage Possible

Although lithium-ion batteries excel in short discharge cycles, they are not designed to serve that purpose. On the other hand, flow batteries fill that requirement. Flow batteries are designed to store energy in fluid electrolytes that are contained in an external tank. For that reason, they are ideal for long-duration applications that can range from 6 to 12 hours or beyond. Those requirements are necessary in renewable-dominant grids.

4. Solid-State Batteries are the Future

Looking forward in time, there is no doubt that solid-state batteries are considered significant in their own right. They aim to change or improve upon current battery technologies in that they are safer because they do not contain any flammable liquids whatsoever. At present, their adoption or production is still in its infancy.

5. Hydrogen Storage and Deep Decarbonisation

In addition to storage in batteries, hydrogen is a flexible form of energy storage in the long term too. Excess energy production from renewables can be employed for the production of green hydrogen through electrolysis, which can be stored and further used for energy generation or direct industrial applications. The storage of hydrogen is significantly important for industries that are difficult to electrify, such as steel production and other chemical industries, maritime transport, and long-distance trucking, for example.

6. Pumped Hydro Still Leads in Size

Although the growth in the use of battery storage and other forms of storage solutions has been quite high, pumped hydro storage remains the leader in terms of installed capacity. Pumped hydro storage comprises more than 90% of the world's energy storage capacity and utilises the difference in elevation between two reservoirs in storing energy. The technology has long-term solutions with a lifespan of more than 50 years.

7. Thermal Energy Storages Lower Peak Demand

Thermal energy storage represents another critical method of managing energy systems. Thermal energy storage involves storing thermal energy, such as heat or cold, and using it at a later date. Thermal energy storage helps mitigate peak power consumption. Thermal energy storage technology takes several forms, such as the molten salt storage system commonly used in concentrated solar power stations, process heat, and cold water storage.

8. Supercapacitors Provide Instant Power

While in a battery, the storage of energy is chemical, in a supercapacitor, the storage is electrostatic. Supercapacitors can be charged and discharged in seconds, can handle millions of cycles, and have a high power rate. Although their energy density is lower compared to a battery, for short energy bursts, such as in applications in electric brakes, frequency regulation, and power smoothing, a supercapacitor is a suitable option.

9. Sodium-Ion Batteries Provide an Economical Alternative

While there are rising concerns about the lithium battery supply chain, sodium-ion batteries are emerging as a cheaper and more environmentally friendly alternative. Sodium can easily be sourced, thereby eliminating any resource and geopolitical concerns. Though sodium-ion battery technology has low energy density compared to lithium-ion battery technology, it can effectively be utilised for stationary battery applications, especially if cost, safety, and long lifetimes are considered as priorities.

10. Batteries from Second-Life Applications: Extending Value and Reducing Waste

Finally, second-life batteries are slowly becoming a sustainable solution. Electric vehicle batteries that do not meet the required standards for use in cars have about 70%-80% of the battery charge that the batteries originally have. This technology enhances the use of batteries for storage in a way that provides a sustainable battery life. For more information, please check Stanford Advanced Materials (SAM).

Frequently Asked Questions

1. What is energy storage and why is it important?
Energy storage allows electricity to be saved and used later, helping balance supply and demand, especially with renewable energy sources.

2. How do lithium-ion batteries compare with other technologies?
Lithium-ion batteries offer high efficiency and energy density, while alternatives like flow batteries and sodium-ion systems are better suited for long-duration or cost-sensitive applications.

3. What role does hydrogen play in energy storage?
Hydrogen enables long-term, large-scale energy storage and supports decarbonisation in industries where batteries are not practical.

4. Why is pumped hydro still so widely used?
Its massive capacity, long operational life, and proven reliability make pumped hydro indispensable for grid-scale storage.

5. How long do energy storage systems typically last?
Lithium-ion systems last about 10–15 years, flow batteries can exceed 20 years, and pumped hydro facilities often operate for several decades.