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When nature decides to rest, storage systems come into play to help renewable energy do its job. Energy storage is the keystone to providing added value to green energy.

About storage

An Ally for Renewables

Renewable energy is inevitably subject to variations in availability. The wind and sun are unpredictable by nature and, consequently, non-programmable. To harness the power of the winds, the Greek god Aeolus decided to lock them up in an amphora. Helios, instead, controlled the light and darkness by pulling the sun with his winged chariot.

Putting the suggestions of mythology aside, technological breakthroughs now make it possible to transform what was only possible for gods in the ancient world into reality: the storage of wind and solar energy to make them available 24 hours a day. All thanks to energy storage systems.

Storage systems are fundamental to the future of renewable energy. They store electricity and make it available when there is greater need, acting as a balance between supply and demand and helping stabilize the grid. Batteries – connected in series – are now some of the most common storage systems (with the exception of pumped-storage hydroelectric systems) and are going through a real technological revolution. Year after year, new materials and cutting-edge technological solutions are introduced, providing greater efficiency, lower costs and a design-to-recycle approach, to obtain a more sustainable product.

Development projections for storage are promising. According to a 2017 IRENA Report, titled Electricity Storage and Renewables, a potential doubling of the growth of renewables – between 2017 and 2030 – will have to correspond to a tripling of the stock of electrical energy available in storage systems: from 2017’s 4.67 terawatt hours to a range between 11.89 and 15.72 TWh in 2030.

History of storage

Energy Storage: Ingenuity and Evolution

Storing Water

In Egypt, to divert the course of the Nile to build the city of Menfi, the first known dam in history was built. The water flow was accumulated and directed toward the complex irrigation systems of the time, to turn barren regions into fertile plains.

The Baghdad Battery

In Persia, a terracotta jar containing a copper cylinder, which in turn contains a single iron bar, is created. The German archaeologist Wilhem König, after analyzing it in 1938, believed the object to be the first rudimentary battery in history.

Collecting Energy for Defense

To defend medieval fortifications, round logs and boulders were stored at the top of hills or high walls. In the event of an attack, their potential energy was released, becoming kinetic energy to strike any invaders in range.

Volta’s Battery

The Italian physicist Alessandro Volta builds the first static generator of electrical energy ever created. The battery is made up of a column of alternating zinc and copper discs, separated by an intermediary layer of felt or cardboard soaked in saltwater.

From the First Dry Cell…

The French engineer Georges Leclanché creates the first dry cell battery, containing no liquid and therefore easy to transport and use

… to Weston’s Solution

The English chemist Edward Weston invents a smaller wet cell battery. The Weston cell will become a reference for the calibration of measuring instruments, like voltmeters, in laboratories. 

Evolve and Reduce

Different materials are used for new kinds of batteries: zinc-air (1914), methane (1936), mercury (1942) and the first alkaline battery (1950). The goal is to create smaller products, to adapt to many uses.

Button Cell Batteries

The first mercury batteries enter the market. The most common ones are flat and round, typical of old wristwatches

Space Storage

Fuel cells are used for the first time on NASA’s Gemini and Apollo spacecraft.

The Forerunner of Non-Battery Storage

The first CAES (Compressed-air energy storage) storage system comes into operation: it uses nuclear energy to compress and inject air into two displacement caverns with 310,000 m³ of volume. 

Mercury ban

The Weston cell battery is banned after new research reveals the toxicity of mercury and cadmium, present in the battery in high concentrations. 

A Nobel Discovery

After 20 years of study, rechargeable lithium-ion batteries are introduced to the market: they allow several charges of large quantities of energy and provide the foundation for the main communication and working tools of today. In 2019, John B. Goodenough, M. Stanley Whittingham and Akira Yoshino will receive the Nobel Prize for Chemistry for their discovery. 

The First Commercial Battery Storage

The so-called Barbados Project becomes operational in November. It’s the first lithium-ion battery system connected to the electrical grid for purely commercial uses.

Storage Comes to Europe

The first commercial-sized electrochemical storage system in Europe is opened near Schwerin, in Germany. The plant holds 25,600 lithium-ion batteries, to store non-programmable wind and solar production.

An Increasingly Affordable Solution

loomberg New Energy Finance reported a downward trend in the cost of solar and photovoltaic plants paired with storage solutions. The average prices of storage systems analyzed (20 MWh of capacity and 4 hours of storage) has fallen by 40% from 2018: a further reduction of 52% is expected by 2030. 

How storage works

The Power-bank of the Electrical Grid

Battery storage systems are able to store the electrical energy produced by renewable plants. Their functioning is comparable to the miniature accumulators in the devices we use every day: they turn a chemical reaction into electrical energy, storing energy to use later, based on necessity. Just like a power bank when our smartphones are low on battery.

When the frequency of the electrical grid falls because of heightened demand, the storage system is able to deliver stored energy in just a few seconds; if the frequency increases due to a drop in demand, the battery charges with the excess energy. This double function is fundamental to the stabilization of electrical grids. 

Lithium battery storage

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Flow battery storage

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Beyond lithium

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Strong points of storage

Never Again Without Energy

Increasingly Common and Affordable

The large-scale production of battery systems allows storage to take hold faster, guaranteeing higher levels of performance.

Toward the Energy Transition

With storage systems, renewables can shift gears, making the process of the energy transition faster and more ready for the future.

Ancillary Services

Storage allows for new services for electrical system security (static reserve, regulation of frequency, voltage and restarting), previously the exclusive terrain of conventional sources.

Did you know?

Crushed Rocks to Store Energy

A battery… with crushed rocks? It seems incredible, but the startup Brenmiller has created an electricity storage system that is a small masterpiece of green engineering.

The bGen™ system allows for the accumulation of energy at high temperatures, based on crushed rock. The solution is based on a heat exchanger and a thermal accumulator.

No dangerous or chemical substances are used in this energy storage system. It’s completely zero-emission: to charge up the storage unit, the system can receive heat or electricity from various sources and can then make it available when necessary. 

Choose your deep dive

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