By Randy Selesky September 20, 2024
A technician working on a Li-ion battery. (Credit: Fahroni)
Long-duration energy storage (LDES) systems are indispensable if we want to achieve our clean energy goals. They will become even more so. By ensuring grid stability and enabling higher penetration of renewable sources, LDES is the catalyst of the next phase of the energy transformation.
Capable of discharging power for extended periods that range from 10 hours to multiple days, LDES systems offer transformative advantages over the currently dominant shorter-duration energy storage (SDES) options, which discharge power for less than four hours.
Supportive U.S. policies have driven the recent renewable energy boom, encouraging investment and development into next-generation clean energy technologies. However, as our clean energy needs evolve, policies must also change to support the oncoming longer-term energy transition.
Let’s look at some of the specific technologies likely to rise as the shift to LDES comes to fruition, as well as the opportunities for U.S. policymakers to better support these energy innovations going forward.
Emerging New Battery Chemistries Challenge Lithium-Ion’s Market Dominance
While Li-ion battery energy storage systems (BESS) and pumped hydro are currently the leading energy storage technologies,1 each comes with limitations that motivate utilities and other stakeholders to look at longer-lasting and more easily applicable alternatives.
A 2023 paper by the National Renewable Energy Laboratory (NREL) cites the difficult challenges of moving beyond four-hour Li-ion batteries.2 Li-ion batteries simply aren’t economically viable for LDES applications. To achieve more energy, Li-ion must add more power and more battery cells that come with a higher CAPEX, more degradation, and increased maintenance from augmentation. Today, that model does not scale very well.
Li-ion’s volatile chemistry also comes with tight over-charge and over-discharge limits that must be followed if utilities want to avoid significant battery damage. Due to its chemistry, a battery operator may only be able to access 80% of a lithium battery’s capacity or may risk premature degradation (which quickly alters a project’s economics). It’s also worth noting that Li-ion has raw materials and recycling challenges that are projected to get worse.3
While pumped hydro is a proven LDES-ready technology, the requirement that facilities be built near large bodies of water at different elevations4 — using pumps to store power and gravity to generate electricity — drastically limits where these systems can be deployed.
At the same time, a recently released Bloomberg New Energy Finance study recognizes several emerging battery technologies that are more suited to supporting LDES use cases, including some that are already cost-competitive with Li-ion (or better).5
In particular, metal-hydrogen battery technology differentiates itself from Li-ion and shows its high potential as an LDES option by providing flexible dispatch at 10–12-hour durations,6 along with stronger overcharge and discharge characteristics. The ability to use 100% of the battery’s capacity allows for steady power output over extended periods.
Using the same basic principles as pumped hydro but with a more versatile set of location requirements, gravity-assisted batteries offer another possible approach to LDES. These systems rely on software-orchestrated cranes and pulleys that raise large bricks of composite materials (up to 500 feet in the air) to store energy and lower them to release power back to the grid.
Don’t Play with Fire
Additionally, the LDES technology transition offers an opportunity to eliminate growing concerns over fire hazards and the risk of explosions or thermal runaway — the uncontrollable process that’s responsible for most battery fires. The perception that energy storage technologies are fire-prone is almost entirely driven by issues with Li-ion batteries.
The fact is that just about every alternative technology likely to lead the LDES revolution — including metal-hydrogen, gravity batteries and others — features improved fire safety and reduced thermal runaway risk.
Anti-Inflation Legislation Propels the Pursuit of Clean Energy Goals
The wide-ranging Inflation Reduction Act (IRA), signed into law in 2022, was a landmark achievement in advancing the country’s clean energy agenda.7 The legislation has provided substantial incentives for clean energy components to be manufactured domestically, bolstered project development incentives, and allocated funds to support growth of energy storage technologies.
While the IRA has helped accelerate the adoption of renewable energy sources, the logical next step is to expand policy initiatives to foster the development of a more diverse array of energy storage technologies and durations. Current policies are lacking in this area, and addressing the gap is critical to establishing a viable market for these valuable energy resources.
The LDES Policy Gap
By acting as a buffer against fluctuations in renewable generation, LDES can smooth out supply intermittencies and ensure a more reliable and consistent flow of clean electricity to homes and businesses.
However, many energy markets and policies currently lack specific incentives or market mechanisms tailored to LDES technologies. Additionally, energy policies and policymakers tend to prioritize shorter-term solutions with shorter-term goals, leaving LDES initiatives at a disadvantage.
Regulatory frameworks in some areas can also inadvertently create barriers to LDES deployment, hindering seamless permitting processes and limiting flexible grid operation rules.
Where Policy Can Advance
To unlock the full potential of LDES and ensure a more stable, economically sound and secure energy future, U.S. policy advances must incentivize research on, development of and deployment of these longer-duration technologies.
“The commitments made by the [United States] and other national governments to accelerate the clean energy transition and rapidly develop renewable energy resources must be matched by efforts to rapidly deploy and scale long-duration energy storage technologies,” Alex Campbell, director of policy and partnerships at the Long Duration Energy Storage Council, said.8
“Setting country-specific targets for energy storage deployment, similar to the recent announcement by the G7, would provide clarity, direction and accountability for policymakers, industry, investors and stakeholders.”
One potential policy approach could be the introduction of tax credits or grants specifically designed to incentivize LDES projects and spur industry growth. Such financial incentives could help offset the higher upfront costs associated with LDES technologies, making them more economically viable and attractive to developers and investors.
Additionally, revisions to existing regulatory frameworks could remove barriers and streamline permitting processes, facilitating the deployment of LDES systems across the country.
Also, policymakers should prioritize the integration of LDES into energy market structures, ensuring that these technologies are appropriately valued and companies are compensated for their essential grid services.
This could involve the creation of new market mechanisms or the adaptation of existing ones to better accommodate the unique characteristics of LDES systems, such as their ability to provide greater capacity and resiliency, improved wind and solar smoothing, and simpler and more effective energy shifting.
Forward-Thinking Policies Open the Door to Lasting Benefits
The United States has the opportunity to lead the world in the development and deployment of LDES systems. By implementing policies that incentivize research, development and deployment, we can not only enhance our energy security and resilience but also contribute to the global effort to mitigate climate change and achieve a decarbonized energy mix.
Sources
- https://tinyurl.com/62bbybtb
- https://tinyurl.com/mr3jj666
- https://tinyurl.com/3xavyk99
- https://tinyurl.com/3sy4na59
- https://tinyurl.com/3cw8bsta
- https://tinyurl.com/ykrp98a8
- https://tinyurl.com/227xnkv7
- https://tinyurl.com/9zjnpjrz
About the Author
Randy Selesky is the chief revenue officer and EVP of product engineering at EnerVenue, which builds metal-hydrogen batteries for large-scale renewable and storage applications. Previously, he was SVP at Greensmith Energy Management Systems.