Lithium-Ion Batteries

The popularity of lithium-ion batteries in energy storage systems is due to their high energy density, efficiency, and long cycle life. The primary chemistries in energy storage systems are LFP or LiFePO4 (Lithium Iron Phosphate) and NMC (Lithium Nickel Manganese Cobalt Oxide).

Why Lithium-Ion is the Preferred Choice

Lithium-ion batteries have a high energy density, a long lifespan, and the ability to charge/discharge efficiently. They also have a low self-discharge rate and require little maintenance. Lithium-ion batteries have become the most commonly used type of battery for energy storage systems for several reasons:

High Energy Density

Lithium-ion batteries have a very high energy density. The high energy density means the batteries can store a large amount of energy in a small space footprint, making them ideal for applications where space is at a premium, such as in electric vehicles or energy storage systems.

Outdoor Distributed Energy Storage Cabinet PW-164

Efficiency and Charge/Discharge Rates

Lithium-ion batteries are efficient at both charging and discharging, and they can handle relatively high rates for both processes. This makes them excellent for applications where energy must be rapidly discharged or put into storage.

Long Lifespan and Cycle Durability

Lithium-ion batteries have a relatively long lifespan compared to many other battery technologies. They can handle a lot of charge-discharge cycles. This long cycle life makes them cost-effective over their lifetime.

Proven Technology

Lithium-ion technology is mature and well-understood, which makes it a less risky choice than newer, less-proven technologies.

Despite these advantages, lithium-ion batteries have some challenges, such as sophisticated battery management systems to prevent overheating and maintain optimal battery health. Choosing the right supplier when looking at lithium-ion-based energy storage systems is important. EVESCO’s battery energy storage systems utilize an intelligent three-level battery management system and are UL 9450 certified for ultimate protection and optimal battery performance.

Lead Acid Batteries

Lead acid batteries are a mature technology that has been around for a very long time. They are often used in applications where the battery isn’t cycled frequently, such as starting cars or emergency backup power.

They are reliable, relatively inexpensive, and widely available. They can also deliver high power. However, lead acid batteries have a lower energy density compared to lithium-ion batteries and a shorter usable lifespan, particularly under deep cycling use. They also require regular maintenance to maintain performance and can harm the environment if not properly recycled.

Lead Carbon Batteries

Lead carbon batteries are a type of lead acid battery but include a layer of carbon in the negative electrode that enhances their performance.

They combine the high C rate capabilities of lead acid batteries with the super-capacitive properties of carbon, enabling them to deliver or absorb bursts of energy quickly. Adding carbon also helps mitigate the detrimental effects of the partial state-of-charge operation, improving the cycle life compared to traditional lead acid batteries. They can be affordable for grid-scale energy storage systems, which are not restricted by space, due to their lower cost and deemed acceptable performance characteristics.

While they offer improved cycle life compared to traditional lead acid batteries, they still don’t match the lifespan of lithium-ion batteries. They also share the environmental concerns of lead acid batteries, requiring careful disposal to avoid lead contamination. Additionally, while including carbon improves their performance, they still have lower energy density than lithium-ion batteries.

Flow Batteries

In flow batteries, rechargeability comes from two chemical components dissolved in liquids inside the system. The most common type is the Vanadium Redox Flow Battery.

Flow batteries can store large amounts of energy and are less sensitive to temperature variations. They have a long lifespan, and their energy capacity (kWh) can be easily increased using larger electrolyte storage tanks. Flow batteries are more complex and expensive to install and maintain than the likes of lithium-ion. The rarity and price volatility of vanadium can also be a concern.

Sodium-Sulfur (NaS) Batteries

Sodium-Sulfur batteries operate at high temperatures and are capable of daily deep cycling. They can typically used for grid storage applications. Due to their high operating temperatures (typically around 350°C), they require significant safety measures and thermal management systems. Due to their size and complexity, they are more suitable for large-scale applications (multiple MWhs) rather than smaller-scale commercial or residential use. NaS batteries are not currently a widely popular choice in the market.

Solid-State Batteries

Solid-state is an emerging battery technology that utilizes solid electrodes and a solid electrolyte instead of the liquid-based electrolytes found in other batteries. They promise significantly higher energy density, improved safety (due to the non-flammable solid electrolyte), and longer lifespans. They also have the potential for faster charging times. However, as of now, they are still in the early stages of development and are yet to be commercially available on a large scale. The manufacturing process is also currently complex and costly. 

Each of these battery types has its advantages and disadvantages. The best choice of technology will depend on the specific needs of a given project, including factors like cost, required capacity, discharge duration, and physical space available.

COMMERCIAL, RESIDENTIAL & UTILITY SCALE BATTERY ENERGY STORAGE

Battery energy storage systems can be found in applications across residential, commercial, and utility scales. Each with different needs, capacities, and applications.

Residential Battery Energy Storage

For individual households, residential battery storage usually ranges from 5 to 15 kWh – enough to offset peak usage periods or provide backup during power outages. They’re typically paired with rooftop solar installations, allowing homeowners to store excess solar power for use during the night or cloudy days. A residential battery energy storage system can provide a family home with stored solar power or emergency backup when needed.

Commercial Battery Energy Storage

Commercial energy storage systems are larger, typically from 30 kWh to 2000 kWh, and used in businesses, municipalities, multi-unit dwellings, or other commercial buildings and applications. These systems can reduce energy costs by lowering demand charges (fees based on the highest rate of energy use during a billing period), load shifting (from high on-peak electric prices to lower cost off-peak prices), providing backup power, and allowing businesses to participate in demand response programs. An example is EVESCO’s 500 kW 500 kWh battery storage system installed at Power Sonic in Nijkerk, The Netherlands, which can integrate with on-site solar and intelligently manage energy use across the building and commercial loads, reducing peak demand and generating energy cost savings.

Utility-Scale Battery Energy Storage

At the far end of the spectrum, we have utility-scale battery storage, which refers to batteries that store many megawatts (MW) of electrical power, typically for grid applications. These large-scale systems can provide services such as frequency regulation, voltage support, load leveling, and storing excess renewable energy for later use. A prominent example of this is the Hornsdale Power Reserve in South Australia. This 150 MW/194 MWh installation has brought stability to the region’s grid and saved millions in grid maintenance costs.

A battery energy storage system’s capacity and specific applications can be customized to fit the user’s needs, whether a single-family home, EV charging stations, or a national electric grid.

Forecasts suggest massive growth ahead for battery energy storage installations as emerging technologies and markets converge. One estimate sees the installed grid-scale battery storage capacity expands 35-fold between 2022 and 2030 to nearly 970 GW. With their immense potential for enabling renewable energy and strengthening grids, realized battery storage systems will only grow in significance for a cleaner and more electrified future.