While portable devices and electric cars are steadily driving global demand for small and medium-sized lithium-ion batteries, there is a third market whose growth is just beginning to pick up: high capacity energy storage facilities. Same technology, but on a whole other scale.

Starting from a very niche position but now experiencing 27% yearly growth, the market for stationary energy storage systems (ESS) batteries is now speeding up faster than for electronic consumer devices and at the same pace as electric vehicles. In fact, its size is expected to triple between 2015 and 2020, increasing its production capacity from 4 GWh to 12 GWh. “After the rapid expansion of the automotive battery market, this will be the second wave,” says Daniel Gloesener, Solvay’s Global Technical Leader for Battery Technologies. “There is no doubt that by 2035, this will be a huge market.”  

Stationary energy for buildings, cities, grids …

As its name indicates, ESS consists in stationary battery installations of all sizes that provide electricity to equally stationary facilities such as houses, hospitals, data centers, entire cities or the general power grid. Their varying capacities and discharge times correspond to a very wide range of applications, from injecting power in the grid for a few seconds for voltage regulation purposes, to shaving consumption or production peaks for several hours.

Solvay of course doesn’t produce the batteries themselves – its customers are battery manufacturers who use its electrolyte additives, fluorinated components, polymers, etc. – but as the chemistry for lithium-ion-based ESS facilities is similar as for mobile phones or electric cars, the same experience and know-how applies. “Yet there is a big game changer at play in this market: the integration of renewables,” explains Daniel. “When the share of renewables in the energy mix goes beyond 25-30%, electricity storage becomes necessary. For the time being, ESS is a very fragmented market lacking a well-defined business model, but that’s going to change.”

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The unparalleled efficiency of Li-ion

And as this market matures and grows, Li-ion is bound to be confirmed as the technology able to meet its needs most efficiently. Alternatives exist, such as Redox Flow batteries (short for reduction-oxidation), a whole different technology based on chemical reactions employed to store energy in liquid electrolyte solutions – but it remains expensive and is only suitable for large facilities with slow response times. 

As for traditional lead batteries, they are still highly prevalent, especially in backup systems (as found in hospitals and data centers, for example), but as the costs of Li-ion batteries decreases - driven by the automotive market -  this will change as well, as the latter offer better response times and capacities. “As soon as the price of battery energy goes below $150/kWh, the ESS segment will start growing faster.” predicts Daniel. “Basically, Li-ion batteries are becoming more and more competitive, and other types of batteries are going to have to prove they are as efficient.” Solvay does also produce silica for separators in lead batteries as well as resins for Redox Flow battery membranes, but other than that, the company’s products chiefly focus on Li-ion technology.

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Solid-state is the next step

But in the background, a brand-new technology holds many promises for the near future: solid-state batteries. Their solid instead of liquid electrolyte (consisting in an inorganic compound or a dry or gelled polymer) guarantees higher stability and longevity. This is a technology currently under development, in particular thanks to the Saft* alliance of European manufacturers, of which Solvay is a member. “Solid-state batteries provide three main advantages: higher safety, competitive cost and better performances (among others, a longer lifetime),” sums up Daniel. “Longevity is an especially important factor for ESS, where the aim is to have facilities that can last 20 to 25 years.”

Here too, the automotive market is likely to be the driver for development. “If we are able to develop a solid-state battery for electric cars, there will be applications for stationary uses as well,” continues Daniel. This shouldn’t be before 2030 or so, but as of now, Solvay is well positioned to be an important part of that development, combining its specific sets of know-how in the fields of fluorides, polymers and inorganic materials with a well developed ecosystem of customers, partners and players all along the battery value chain.

*Saft is a wholly-owned subsidiary of Total specializing in battery solutions for industrial applications