Steven Chu (Stanford) (May 2023)

Steven Chu (Stanford Professor) – Keynote (May 2023)

Chapters

00:00:12 Global Energy Storage Solutions for Decarbonization

Summary of Progress and Challenges in Renewable Energy:
Prices of renewable energy sources, like solar and wind, have decreased significantly, making them cost-competitive with fossil fuels. However, to fully integrate renewable energy into the grid, long duration energy storage is needed. Long duration energy storage is defined as storage that can last for more than three days.

Challenges in Long Duration Energy Storage:
Current long duration energy storage technologies, such as batteries, are expensive and have limited capacity. Pumped hydro storage is a mature technology but requires specific geographical features and can have environmental impacts. Compressed air energy storage has not yet been commercially viable due to challenges in compressing and expanding gas. Thermal storage is a promising technology with good scaling potential but requires efficient heat transfer and high temperatures.

China’s Leadership in Pumped Hydro Storage:
China is the global leader in pumped hydro storage, with plans to build more capacity than the rest of the world combined. China’s focus on pumped hydro storage is driven by its commitment to renewable energy and its need for reliable energy sources.

Zinc Flow Batteries and Heat Storage Innovations:
New developments in zinc flow batteries offer improved longevity, efficiency, and cost-effectiveness. Heat storage technologies, such as the Carnot engine, have the potential for efficient energy storage and conversion.

Challenges with Hydrogen:
Hydrogen production through electrolysis is expensive and requires large amounts of electricity. Hydrogen is very leaky and has the potential to increase methane concentrations in the atmosphere, which is a potent greenhouse gas. Detection of hydrogen leaks is difficult, making it challenging to monitor and prevent leaks.

Future of EV Batteries:
EV battery technology is rapidly improving, with energy density and cost per kilowatt hour decreasing significantly. GM has announced a target of $87 per kilowatt hour for battery packs in the next four years.

00:12:44 Innovative Battery Technologies and Strategies for the Energy Storage Market

Scarcity of Raw Materials for EV Batteries:
Cobalt and nickel are too expensive for EV batteries. All OEM manufacturers are switching to iron phosphate batteries. Lithium availability is also a concern for utility-scale batteries.

Alternative Materials for Utility-Scale Batteries:
Zinc, sodium, iron, and other materials are being explored as cheaper alternatives to lithium. Aqueous batteries are safer than organic batteries.

Challenges with Metal Anodes:
Metal anodes, like zinc foil, can form dendrites when charged too quickly. Dendrite formation can lead to battery instability and fires.

Suppressing Dendrites:
Researchers are exploring various strategies to suppress dendrite formation in metal anodes. One approach involves creating a barrier on the metal surface that allows ion conduction but prevents dendrite growth.

Hexagonal Boron Nitride as a Barrier:
Hexagonal boron nitride (h-BN) is a 2D material that can be used as a barrier to suppress dendrites. h-BN has been shown to improve the cycling stability of lithium-sulfur batteries. It may also be effective in aqueous batteries with metal anodes.

Lithium Extraction from Seawater:
Chong Liu developed a method to extract lithium from seawater. The process involves passing seawater through an iron phosphate material, which selectively absorbs lithium ions. The recovered lithium can be used in battery cathodes.

Improved Lithium Recovery:
By engineering the intercalating compound, the lithium recovery ratio from seawater can be significantly improved. This reduces the amount of sodium contamination in the lithium, which extends battery life.

Pump Storage:
Pump storage is a well-established energy storage technology. It involves pumping water uphill when there is excess electricity and releasing it downhill to generate electricity when needed. Pump storage is cost-effective and has a long lifespan.

Political Opposition to Pump Storage:
Political opposition, particularly in California, is hindering the development of new pump storage projects. Hydroelectric dams, which are used for pump storage, are facing pressure to be torn down due to environmental concerns.

Transmission and Storage:
Transmission and storage are complementary technologies. Both are necessary for a reliable and resilient energy system.

00:18:30 Challenges and Solutions in Energy Storage

Abstract

Addressing the Future of Energy Storage: Challenges and Innovations in Long-Duration and Utility-Scale Systems

Leading the Charge: A Comprehensive Look at Long-Duration Energy Storage

In the quest for a sustainable energy future, the pivotal role of long-duration energy storage (LDES) cannot be overstated. As renewable sources like solar and wind gain traction, their intermittent nature calls for robust storage solutions to maintain grid stability. LDES stands at the forefront of this challenge, balancing energy fluctuations and ensuring a steady electricity supply. However, the journey is not without obstacles.

The current landscape of LDES is dominated by technologies such as pumped hydro storage and compressed air energy storage. While reliable, these methods face hurdles in scalability and efficiency. Geographical limitations and high infrastructure costs particularly impede the expansion of pumped hydro storage, the most prevalent form of LDES.

A critical barrier to widespread adoption of LDES technologies is their cost. To viably replace natural gas peaking plants, these systems must achieve a price point below $10-20 per kWh. Current costs, hovering between $200 to $300 per kWh, present a significant challenge.

Emerging Technologies: Flow Batteries, Thermal Storage, and Hydrogen

In the field of promising LDES technologies, flow batteries, thermal storage, and hydrogen offer glimpses of hope. Flow batteries, notably vanadium and zinc-based, have seen advancements in membrane technology, boosting their efficiency and lifespan. Thermal storage systems excel in storing vast energy amounts as heat, with innovative designs like Bob Laughlin’s heat engine pushing the boundaries of energy conversion efficiency.

Hydrogen, particularly green hydrogen produced from renewable sources, emerges as a clean energy carrier. Despite its potential, the high cost of electrolyzers, hydrogen leakage, and inefficient detection methods remain significant challenges.

Lessons from EV Batteries: A Path Forward for LDES

The evolution of commercial electric vehicle (EV) batteries offers valuable insights for LDES. With accelerated learning curves leading to rapid cost reductions, the advancements in energy density and cost of EV batteries serve as a blueprint for the future development of LDES technologies.

Utility-Scale Batteries: Material Considerations and Innovations

Moving to utility-scale batteries, the narrative shifts slightly. The high cost of lithium-ion batteries renders them impractical for large-scale applications, steering research towards more economical materials like zinc, sodium, and iron for aqueous batteries. Safer than their organic counterparts, aqueous batteries are more suited for extensive installations, though the issue of dendrite formation during rapid charging remains a hurdle.

Lithium Extraction from Seawater: A Sustainable Approach

In an innovative breakthrough, Chong Liu’s method of extracting lithium from seawater presents a sustainable and cost-effective alternative for large-scale lithium production. By passing seawater through an iron phosphate material, a lithium-rich compound is obtained, potentially revolutionizing lithium availability for battery production.

The Composite Picture: A Mix of Technologies for Energy Storage

Looking at the broader energy storage landscape, a combination of chemical batteries, hydrogen pump storage, and heat storage appears necessary to meet diverse storage needs. Pumped storage, while mature, faces political challenges, highlighting the need for both transmission and storage solutions in a resilient energy system.

Addressing Transmission and Environmental Challenges

Transmission line siting, crucial for efficient energy distribution, encounters opposition due to environmental concerns, particularly in areas valued for hunting and fishing. Political obstacles also emerge in efforts to streamline transmission permitting, underscoring the complexity of integrating new technologies into existing frameworks.

In the context of pumped hydro storage, the issue of methane emissions from water level fluctuations presents an environmental concern. Though these emissions are relatively minor compared to other sources, strategies to mitigate them, such as suppressing organic matter decomposition and modifying microbial activity, are under exploration.

Recent Developments and Challenges in Long-Duration Energy Storage Technologies

* Scarcity of Raw Materials for EV Batteries: Cobalt and nickel prices have led to a shift toward iron phosphate batteries. Lithium availability is also a concern for utility-scale batteries.

* Alternative Materials for Utility-Scale Batteries: Research focuses on cheaper alternatives to lithium, such as zinc, sodium, and iron, for aqueous batteries. Metal anodes, like zinc foil, can form dendrites when charged too quickly, leading to instability and fires. Researchers are exploring methods to suppress dendrite formation, such as using hexagonal boron nitride (h-BN) as a barrier.

* Improved Lithium Recovery from Seawater: Engineering the intercalating compound in Chong Liu’s method can significantly improve the lithium recovery ratio from seawater, reducing sodium contamination and extending battery life.

* Political Opposition to Pump Storage: Hydroelectric dams used for pump storage face pressure to be removed due to environmental concerns. Efforts to streamline the siting process for transmission lines encounter resistance from various agencies.

* Methane Emissions from Pumped Hydro Reservoirs: Methane emissions from pumped hydro reservoirs are relatively minor compared to other sources, but research is ongoing to develop methods for suppressing them.

Concluding Thoughts

The transition to a reliable and sustainable energy system hinges on the development of cost-effective and scalable LDES technologies. Innovations in flow batteries, thermal storage, hydrogen, and utility-scale batteries, coupled with breakthroughs in lithium extraction, pave the way forward. However, overcoming technical and economic challenges, along with addressing transmission and environmental issues, remains critical. The progress in EV battery technology and the ongoing research in pumped hydro storage offer valuable lessons and avenues for future exploration, marking an exciting era in the evolution of energy storage solutions.

Notes by: datagram

Steven Chu (Stanford Professor) – Keynote (May 2023)

Chapters

Abstract

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