Thermal vs. electrochemical energy storage: a comparison

Thermische und elektrochemische Energiespeicher im Vergleich

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With the increasing share of renewable energies, the need for energy storage options to compensate for the fluctuations that occur is also growing. If energy generation and consumption are decoupled in time, this not only makes a positive contribution to grid stability, but can also increase security of supply on the consumer side, increase energy efficiency and reduce energy costs. Energy storage systems offer promising advantages, particularly for industrial companies in energy-intensive sectors. Various energy storage technologies are available. Thermal and electrochemical energy storage systems have already been tried and tested in industrial applications. We have compared the solutions.

Electrochemical energy storage systems: how they work and areas of application

Electrochemical energy storage devices include both batteries and accumulators, colloquially known as rechargeable batteries. They store and supply electrical energy through reversible electrochemical reactions in which ions move between a positive electrode (cathode) and a negative electrode (anode) through an electrolyte. When charging, the ions move to the anode for storage. During discharge, they return to the cathode, releasing electrons that flow through the external circuit to supply energy.


Lithium-ion batteries now play a particularly important role in the industrial sector, as they can be used in a variety of ways. Even though they are referred to as batteries, they are actually accumulators. This type of energy storage device has been used for some time to buffer electricity from solar or wind energy. Lithium-ion batteries are particularly suitable for short-term energy storage due to their fast response times. In industrial applications, large lithium-ion battery systems are used to store energy and make it available at peak load times. They are also used in modern electric vehicles.  

Advantages of lithium-ion batteries

Lithium-ion batteries have a high energy density, which means that they can store large amounts of energy in a comparatively small and lightweight package. This makes them especially suitable for mobile applications such as electric vehicles and portable electronics. Their charging and discharging efficiency is high, often exceeding 90 per cent. This means that very little energy is lost during the storage process, making them economically attractive. They also have a low self-discharge rate, meaning they can hold their charge over longer periods of time – without significant energy losses.

Challenges when using lithium-ion batteries

Despite falling prices, lithium-ion batteries remain more expensive than some alternative storage technologies. High costs due to rising demand for the required raw materials such as lithium and cobalt contribute significantly to the overall costs. Improper handling or extreme conditions can cause the batteries to catch fire. Extensive safety measures and complex monitoring systems are therefore essential, resulting in high operating costs. If they are used as energy storage systems in industrial plants, the individual storage units must be widely spaced. This is necessary due to the risk of fire and for maintenance purposes, which enormously increases their space requirements.


The production of lithium-ion batteries is also not harmless to the environment: the mining and processing of lithium and other materials can have a significant negative impact on the environment, as water consumption is extremely high. The recycling of lithium-ion batteries also poses a challenge.

ThermalBattery™: How the thermal energy storage system works

Thermal energy storage systems play an important role in the efficient utilisation and storage of thermal energy generated in various industrial processes and in the use of renewable energies. This type of energy storage includes sensible heat storage, which stores heat by increasing the temperature of a medium, latent heat storage, which utilises phase change materials to store heat, and thermochemical storage, which stores heat through reversible chemical reactions.


An innovative and market-proven technology in this area is the ThermalBattery™ from ENERGYNEST, which is characterised by high efficiency and flexibility. The ThermalBattery™ stores energy in the form of heat and releases it again when required. The heat is transferred to the storage medium, a specially developed high-performance concrete, using steam or thermal oil as the heat transfer fluid.


In industry, the heat storage system offers various possible applications. For example, the ThermalBattery™ can be used to supply production processes with renewable energy. This works by directly charging it with hot thermal oil from solar thermal power plants or by converting green electricity into thermal energy, which is then stored in the ThermalBattery™. In addition, previously unused waste heat or excess steam can be captured, stored and released as process heat or steam when required, which significantly improves the energy efficiency of industrial plants.  

Advantages of ThermalBattery™ compared to lithium-ion batteries

The ThermalBattery™ is extremely robust thanks to the high-performance thermobeton used and has a significantly longer service life than lithium-ion batteries. It also has virtually no loss of performance. Its efficiency is over 98 per cent. In contrast to lithium-ion batteries, the ThermalBattery™ can continuously release energy over a period of several hours to several days, which ensures a reliable energy supply even during longer power outage phases.


The ThermalBattery™ storage technology is based on cost-effective and readily available materials that are also fully recyclable. Disposal after use is therefore uncomplicated and significantly more environmentally friendly. The thermal store is also virtually maintenance-free, which significantly reduces operating costs compared to other storage systems and increases their reliability.


The modular design enables easy scalability and also ensures that the energy storage system takes up comparatively little space when integrated into industrial processes. Last but not least, the ThermalBattery™ offers significantly greater versatility on the charging and discharging side – and can therefore be used in a variety of different industrial processes, including the storage of waste heat and integration into renewable energy systems such as solar thermal power plants.

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