Energy storage will be one of the key factors in the evolution towards a new market model in which fossil fuels and especially gas, will have less and less importance. Nowadays, storage systems have become widespread and are usually included in utility-scale projects. This change of paradigm has been possible thanks to falling battery costs, increased efficiency due to technological innovation and the extensive awareness that storage is the best solution to the intermittency of renewables.

Batteries are the most widely used storage systems. But not all the batteries are the same, nor do they serve the same purpose. When deciding which kind of battery will maximize the performance of an energy installation, several factors must be taken into account. In this decision, the best thing for an investor with little experience in the sector is to hire a company as an EPCist to provide the ‘turnkey’ project and take on the subsequent O&M work.

International Energy Agency (IEA) calculates that in a few years around 10,000 GWh of storage batteries will be needed worldwide to meet the climate and sustainability goals agreed upon at recent international summits. Countries such as the United Kingdom and Australia, where legislation and institutional initiative have stimulated the exponential growth of storage, are already standing out.

Considering the various factors, batteries can be classified in different ways.

Manufacturing technology

Energy storage is a sector closely linked to innovation and research. . The constant target is to find new, more efficient materials that are simpler, cheaper, and more sustainable to extract, and that exist in sufficient volume so that their commercialization doesn’t depend on just a few markets, such as China. The aim is also to make them increasingly recyclable materials with less impact on the environment.

E22 is a company specialized in the construction of vanadium redox flow batteries (VRFBs), a solution used in projects around the world, which has a number of interesting advantages. For example, they have a service life of more than 10,000 cycles, do not overheat, require little maintenance and are 90% recyclable.

However, lithium-ion batteries are still the most common due to their lower costs and characteristics. These products are presented in containers or cabinets, are easy to transport, install and maintain, and are scalable to adapt to larger or smaller renewable energy projects, such as those planned by E22 in the United Kingdom in the next few months.

Their capacity (different kinds of power)

E22 has a large portfolio of products to be able to respond to the needs of each client and each project in a personalized way. Energy storage batteries can range in power from 15 kW/kWh to hundreds of MW/MWh. The smaller ones, due to their size and characteristics, can be directly integrated into energy or domestic projects, while the larger ones are usually assembled in containers that facilitate the integration and transport, and that are located at a specific point.

The choice of size and power-to-capacity ratio depends on the intended use of the battery. For energy arbitrage, it is ideal to opt for solutions with more capacity than power in order to be able to move the most energy at peak times.

However, if the grid regulation is required, power will be the determining factor as large amounts of energy are not needed.

The technology is essentially the same, irrespective of the battery size. The only difference is the power-to-energy ratio (MW/MWh) which will determine the rating of cells between 2C and 0.5C.

Their purpose: hybridation, arbitrage, etc.

One of the major advantages of batteries is they are hybrid solutions that can be used with any type of energy, but their use is being promoted especially with non-constant energy sources in order to increase their efficiency. The purpose is to store surplus energy during periods of higher production and supply this electricity at times when there is no production.

However, batteries have another interesting function: grid arbitrage. It is a process that consists of storing energy at the highest production peaks, i.e., when market prices are lowest, and releasing it when production decreases at therefore, higher prices. In these cases, a type of product is needed that allows high storage capacity and deep discharges to be effective, and whose useful life is not affected by these cycles.

E22 manufactures its batteries entirely in Spain, specifically at its factory in Chiva (Comunidad Valenciana), thus guaranteeing its clients finished products with European quality standards and little dependence on imported materials.