Battery Technology The future of battery energy storage systems

| Author / Editor: Luke James / Florian Richert

There are several challenges and hurdles facing battery energy storage systems of the future. In his PCIM Europe keynote, Dr. Ahmed Elasser highlights how these challenges could be addressed to facilitate further development and deployment.

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GEs Reservoir.
GEs Reservoir.
(Source: General Electric)

Electrical energy storage has become an important topic of discussion across many industries, but it is perhaps in the electrical grid and related applications where electrical energy storage and battery energy storage systems (BESS) are most important.

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Indeed, energy storage has become an integral part of our modern world. The most commonly referenced example, the lithium-ion (Li-ion) battery, which enabled the personal electronics revolution in the early 1990s and the first commercial electric vehicles (EVs) in the 2010s, have recently expanded into the power grid to provide a boost to renewable energy generation and increase the efficiency of transmission and distribution.
The goal for grid operators is to not just offset their carbon footprints but to also move away from the just in time nature of the electrical grid. Currently, operators are constantly balancing supply and demand, but BESS are making huge inroads with flexible, high energy dense, modular solutions that can provide hours’ worth of storage times. It also responds fast to changing levels of demand.

What’s currently driving BESS?

In the keynote, Dr. Elasser highlights four things that are disrupting the power sector and driving technological developments in the arena of energy storage.
Decarbonisation at the grid level is the big one, with renewables expected to represent 30%+ of global electricity by 2040. Digitisation is also having a huge impact. The growing number of connected devices and smart sensors (and the IoT on the whole) is enabling decision makers to act with more confidence. Also driving developments in the power sector are decentralisation, where end-users (consumers) are becoming active actors of the power system (“pro-sumers”), and overall electrification in the energy ecosystem.

How are BESS used in the grid today?

Today, BESS represents less than 5% of the total portion of the energy grid. However, it’s growing fast, and Li-ion chemistries are dominating as the technology of choice for a range of energy storage applications. This is due to their high energy densities and smaller size and weight, which lead to more flexibility and ease of installation.

To say that Li-ion BESS are perfect would be disingenuous, however. Li-ion batteries are infamously flawed, namely in terms of safety. It was only a few years ago when Samsung’s Galaxy phones were plagued by ‘exploding’ batteries. This is a risk not to be taken lightly when it comes to large-scale energy storage applications like that of power grids.

Other challenges facing Li-ion include cycle life and end-of-life, however, lots of time, effort, and money is being poured into Li-ion to make them safer, last for thousands of cycles, and recyclable.

How are these challenges being addressed?

Major advances in the field of battery research are enabling researchers to achieve transformative performance spanning energy and power density, cost, lifetime, charge/discharge times, and capacity. And, according to Dr. Elasser, General Electric (GE) is leading the charge towards the next generation of high capacity, reliable battery energy storage systems.
One of GE’s latest deployed systems is the GE Reservoir in California, a comprehensive energy storage platform that delivers customized storage solutions to help customers address new challenges in a rapidly transforming power grid.

The Reservoir is a grid-scale energy storage system that is perfectly balanced to match power supply and demand, preventing crashing and downtime. Expanding on GE’s 10-year footprint in the energy storage space, the Reservoir allows producers to “decouple when energy is produced and when it is consumed.” It is also capable of holding enough power to restart an entire power plant.
It is innovations like GE’s Reservoir that will enable lofty energy storage capacity goals, particularly in sunny areas like Arizona, for example, which plans to add 3,000 megawatts of storage capacity by 2030, and California, where planning is underway for the state to source 50% of its electricity from renewable sources, also by 2030.

Why is energy storage so important now?

In the past, it was much easier to predict power supply. This is because power was generated by steady sources such as thermal and nuclear plants. However, with the advent of renewable sources like wind and solar, which often depend on and are influenced by unpredictable weather, everything became much more complex. With energy storage, we can weather (no pun intended!) some of this intermittency and smooth things out on the power generation side.
Engineers have long since been looking for efficient, flexible, and effective ways of storing large amounts of energy. And although some successful innovations like pumped storage have been used in plenty of applications, grid-scale batteries have until now remained out of reach. With the rise of electric vehicles bringing lots more innovation in the battery space and the growth of solar power significantly driving down cost, now is the time when energy storage matters.