North America | September 11, 2024

Are Batteries the Best Option for Energy Storage?

While other options exist, lithium-ion batteries are becoming the preferred way to store energy from renewable energy sources.

 

Image for illustration purposes.

The transition to renewable energy sources like solar and wind has highlighted a significant challenge: the intermittency of these energy sources. When the sun shines or the wind blows, there is often an oversupply of energy, but this can lead to shortages when these sources are not available. To address this issue, effective energy storage solutions are essential.

Current Energy Storage Technologies

Pumped hydro storage currently dominates the global energy storage landscape, accounting for over 90% of high-capacity storage. This method involves using excess electricity to pump water into elevated reservoirs. When energy demand peaks, the stored water is released to generate electricity through turbines. Although this system is reliable and efficient, it has limitations, including high capital costs and specific geographical requirements, as it needs to be located in mountainous regions with sufficient water resources.

The Rise of Lithium-Ion Batteries

Lithium-ion (Li-ion) batteries have emerged as a popular alternative for energy storage. Their use has expanded significantly, with large-scale installations capable of storing between 100 to 800 megawatts (MW) of energy. Facilities like Moss Landing in California exemplify this trend, boasting a capacity of 750 MW/3,000 MWh. The rapid decline in lithium battery prices and improvements in energy storage capacity have been largely driven by advancements in the automotive industry, particularly in electric vehicles (EVs). Li-ion batteries have a higher voltage output per cell compared to other battery types, which reduces the number of cells needed in applications.

Challenges with Lithium-Ion Batteries

Despite their advantages, Li-ion batteries face several challenges:

  • Degradation: Over time, the performance of Li-ion cells decreases, limiting their storage capacity.
  • Recycling and Sourcing: Concerns about the environmental impact of lithium and cobalt mining have been raised, particularly regarding ethical sourcing practices. Cobalt mining, especially in the Democratic Republic of Congo, has been linked to child labour and unsafe working conditions.
  • Safety Risks: Some Li-ion batteries are flammable, and there have been incidents of battery storage facilities catching fire due to thermal runaway, often attributed to poor installation practices.

To address these issues, the International Electrotechnical Commission (IEC) has developed standards for battery safety and recycling, including IEC 62933-4-4, which focuses on the environmental impacts of reused batteries.

Emerging Battery Technologies

New battery technologies, such as solid-state batteries (SSBs), are being explored as potential successors to Li-ion batteries. SSBs use a solid electrolyte instead of a flammable liquid, offering enhanced safety and the possibility of using varied materials for the battery’s components. However, true solid-state batteries are still in development and face challenges such as high costs and market acceptance.

Hybrid semi-solid batteries, which contain small amounts of liquid or gel, may serve as a transitional technology, potentially offering improved performance while the market adapts to fully solid-state solutions.

Conclusion

While lithium-ion batteries currently dominate the energy storage market, their limitations and safety concerns highlight the need for ongoing innovation and the exploration of alternative technologies. As the demand for efficient and reliable energy storage solutions grows, the development of new battery technologies will be crucial in supporting the transition to a sustainable energy future.

Source: pv magazine