What is energy storage?

Energy storage means all the methods for energy conservation. These are mainly used to efficiently manage energy by balancing the times of low production or high demand with those of high production or low demand.

Storing energy is indispensable in the framework of the energy transition and efficiency because it facilitates the use of renewable energy and helps address climate change.

How have energy storage methods evolved over the years?

Energy storage has been present throughout the history of mankind. Some of the most relevant milestones include:

• 4,000 BC.: in Egypt, a dam was built to accumulate and channel the water coming from the Nile River to build the city of Memphis. The water was used to create irrigation systems.
• 247 to 224 BC.: according to a study by the German archaeologist Wilhelm König, what may have been the first battery in history was created in Persia. It was made in a terracotta vessel with an integrated copper cylinder and a single iron bar.
• 1799: Italian physicist Alessandro Volta built the first electrodynamic generator, a battery with alternating zinc and copper discs separated by a layer of felt or cardboard soaked in salt water.
• 1866: French engineer Georges Leclanché created the first dry cell, which was easier to transport compared to that of his predecessor Volta.
• 20th century: manufacturing batteries began to be done with new materials to make them smaller, more transportable, and more adaptable. The most common were zinc-air, methane, and mercury.
• 1960s: cold fuel cells powered NASA’s Gemini and Apollo spacecraft. According to research funded by NASA, fuel cells could be the future stars of energy because their only waste is pure water.
• 1978: the first CAES (compressed air energy storage) system went into operation, using nuclear energy to compress and inject air.
• 2008: The Barbados Project was launched, the first lithium-ion battery system connected to a power grid for supply and commercial use.
• 2014: a plant with more than 25,000 lithium-ion batteries, the first electrochemical energy storage system, opened in Germany. This plant sought to accumulate unscheduled wind and solar production.

What energy storage systems are there today?

While energy can be easily generated and transformed, storing it in large quantities is complex. Storage systems can be categorized by their capacity:

1. Large-scale storage (GW): reversible hydroelectric systems (pumping) and thermal storage.
2. Storage in networks and generation assets (MW): such as cells and batteries; capacitors and superconductors; and flywheels.
3. End-user storage (KW): used at a residential level and classified into batteries, superconductors, and flywheels.

Depending on the energy storage methods, systems may be electrical, electrochemical, mechanical, potential, or thermal. Here are some of the most common ones:

• Battery: they store energy in chemical compounds that are capable of generating electrical energy. They are quick to install, responsive, and come in multiple varieties. According to studies, lithium batteries will be able to reduce up to 30% of carbon emissions by 2030.
• Hydraulic pumping: this large-scale system set up at hydroelectric power plants stores water and generates energy with the turbines’ force. It is the most efficient, fast, and cost-effective system and provides stability to the electrical system worldwide.
• Compressed air: this method of storage is carried out in underground facilities through a reversible motor. It works by accumulating ambient air at high pressures by moving an energy generator to supply it.
• Hydrogen: one of the solutions to conserve electricity without generating greenhouse gases during combustion, production, storage, and use. It comes from natural gas and can be preserved for a long time.
• Thermal storage: this method can store heat or cold regardless of the temperature conditions, location, or power at which it is performed. The storage material for this type of energy must have good density, thermal conductivity, and chemical and mechanical stability. Such is the case with thermal energy storage in aquifers, where water is pumped from hot wells to heat a building in winter or vice versa.
• Supercapacitors: these devices store energy in large quantities and deliver it almost instantly.

What is the largest energy storage project in the world?

That would be Sun Cable, an Australian project developed in 2019 that aims to combine up to 20 GWp of photovoltaic solar energy with the largest energy storage battery of 36 to 42 GWh and a 4,200 km long submarine cable to supply electric power to Singapore.