Lithium Ion Batteries and the Future of Grid-Scale Energy Storage 

September 23, 2019 | Roger Lin believes batteriesparticularly lithium ionmay hold the power to salvage our electrical grid. Lin, who is the Vice President of Marketing at NEC Energy Solutions, recently spoke with Mary Ann Brown, on behalf of Battery Power Online, about his vision for the future of batteries.  

Before his current role in marketing, Lin worked in R&D with ceramic materialshaving earned both his undergraduate and graduate degrees in the Engineering Sciences. Lin’s engineering background informs his opinion on batteries. Many will argue the benefits of using one chemistry over anotherHowever, Lin says that when creating an energy storage system, its performance, safety, and reliability rests ohow it’s put together. He emphasizes that it’s not just the chemistry, as with technology innovation the chemistry of batteries will change. The real key, he says, is the entire system. 

Editor’s Note: Lin’s colleague, Tom De Luciawill be speaking at the Lithium-Ion Battery Consumer Safety meeting at the Battery Safety Summit, October 22-25, in Alexandria, Virginia. Mary Ann Brown spoke with Lin in advance of the summit. Their conversation has been edited for length and clarity for inclusion in Battery Power Online. 

Battery Power Online: Can you tell us a little bit about NEC Energy Solutions? 

Roger Lin: NEC Energy is focused on providing fully integrated stationary energy storage systems that are safe and reliableThey have applications for the electrical grid and are used by utility companies, power producers/generators, as well as industrial electricity consumers implementing energy storage solutions to save money on their electricity bill. In very simple terms, an energy storage system consists of three parts: the battery, a power conversion system, where DC electricity from a battery is converted into AC electricity to be made compatible with the electrical grid, and finally, sophisticated software controls to make it valuable to the owner. This combination of hardware and software work cooperatively to ensure the most efficient use of energy and create value for our customer. 

Energy storage can benefit both consumers and generators of electricity. Newer, cleaner sources of energy like renewable energy can especially benefit. The variable nature of wind and solar energy mean they are not as controllable as other energy sources. But with stationary energy storage, wind and solar farms can control the way they output power to the grid. Not only can battery power help integrate renewables into the grid, it can stabilize the frequency of the grid, and help traditional energy generation, like coal or fossil fuel power plants to operate more efficiently. 

You mentioned that batteries for grid-scale energy storage is gaining interest. What else can you tell us about batteries and the grid?  

Currently the predominant battery type is lithium ion. Its combination of durability, energy density, and cost have ensured its ubiquity in automobiles and consumer electronics as well as its current dominance as stationary power storage for the electrical grid. It has helped renewables like photovoltaic or wind energy enter the market and helped stabilize the frequency of more volatile grids. Stored power also allows for shifting electricity in time to a less costly or more valuable time period. 

The sodium sulfur battery is a battery type also currently in use for grid-scale energy storage. This is a molten sodium battery that’s good for very long duration applications, six hours or more, and is intended to compete with pumped storage, a hydroelectric energy storage system.  These two chemistries, lithium ion and sodium sulfur, currently dominate stationary energy storage for the grid.  

However, there are now some flow batteries on the market able to provide four or more hours of low power. These use chemicals like vanadium, bromine, zinc, iron, etc., and flow liquids over a stack to create electricity or to absorb it. There aren’t many right now, but we’re starting to see them in pilot projects, as well as some larger-scale projects overseas. We’re watching very closely to see what the best fit will be for those, factoring in durability, power-to-energy ratio, and overall cost. You’ll see different technologies fit different applications in different ways. There is no single battery that fulfills all applications equally well. That’s why it helps to have an understanding of the characteristics of each of the chemistries. 

The electrical grid is a complex and aging infrastructure. What can batteries do to help?  

Batteries have only recently been introduced to the electrical grid in a large way. Most of the stored electricity has been in the form of pumped-storage hydroelectricity, or “pumped hydro.” This is a system of water pumped uphill to store energy and then released to a lower elevation to discharge that energy. While these are effective they are also enormous civil works projects that take a long time to site and permit. They disrupt the environment by carving out mountainsides and creating artificial lakes to move water up and down the height differential necessary for its potential energy. However, with batteries, because they can be made much smaller, are more energy dense, and can be distributed throughout the network as opposed to in large centralized locations, this problem disappears.  

Not only is the utility grid aging, we’re seeing a change in the generation mix with less fossil fuel generation and greater representation from greener energy generators. Fossil fuels are carbon emitters, but are also very easily controlled, where wind and solar are not. That’s where battery storage comes in. The energy stored in these batteries can bridge the gaps left by the intermittent variable nature of green energy, or a changing generation mix, while enabling the grid to be a lot more flexible and adaptable.  

Energy storage, powered by batteries, is set to become a new pillar of the electrical grid, as integral as the wires that transmit electricity and the generators that produce it. Batteries that can be made much smaller, store more energy, and be distributed throughout the network, as opposed to in large centralized locations, will enhance the resiliency of the electrical grid, protecting against current and future threats to our power grid. 

How long can we expect lithium ion to dominate the battery market? 

I believe we will see lithium ion batteries continue to dominate the battery market for the next five to seven years, if not more, simply because they serve such a diversified market. Lithium ion doesn’t just support stationary energy storage, it’s found throughout the transportation sector in the rapidly growing EV market, as well as in the portable electronic devices upon which we depend. Because it’s so intertwined in our lives lithium ion will continue to be the battery of choice. 

But innovative technologies will develop and seek a place within the battery hierarchy. It could be that flow batteries or batteries with a chemistry combination not yet seen enter the market to compete with lithium ion. However, I think they lack the market diversity and that’s going to prevent them from achieving the economic success of lithium ion, especially as we see prices dropping from 15-20% per year. 

Lithium ion does have a reputation for being somewhat volatile under abuse conditions, though. The nature of the systems currently being deployed are quite large and concentrated. With so much energy amassed in a single area the storage hazards increase. It may be the case that as projects grow, a battery technology that tolerates abuse better than lithium ion is preferable. This could be the circumstance that creates the opportunity for new technologies to join the industry.