Tank terminals will continue to provide vital storage and logistics services for liquid fuels, even as our sector will be called upon to integrate no-carbon and low-carbon liquid fuels to a growing degree in the decades to come.
One emerging area of discussion is the role that liquid terminals can play in contributing to the strength and resilience of the electrical grid.
One high-potential pathway to achieve this goal is for tank terminals to provide sites for industrial-scale batteries capable of housing hours, days or even weeks of electricity storage for a locality or region. There are several possible liquid-based technologies that could be sited on tank terminals to provide this service, termed in the electrical industry as “long duration energy storage,” or LDES.
The case for LDES
LDES can harmonize the output of highly variable solar and wind energy sources, easing the pressure on transmission and distribution networks. LDES technology could offer substantial benefits in regions with abundant renewable resources where the timing of supply and demand do not coincide. By acting as energy reservoirs, LDES systems can effectively manage demand fluctuations through peak or load shaving and time-of-use programs. Timeof-use pricing is a rate schedule that adjusts electricity prices based on when it’s being used. In states like California, LDES adoption is paving the way to retire traditional “peaker” plants, pushing the boundaries for more renewables-centric energy generation models.
Liquid terminals are positioned to play a critical part in optimizing wind and solar outputs, while simultaneously reducing transmission and distribution costs by housing LDES infrastructure. One candidate technology for this purpose is the group of battery chemistries known as “flow batteries.”
The appeal of flow batteries extends beyond energy storage capabilities, thanks to numerous additional benefits. These include lower maintenance requirements, increased affordability and a longer life cycle — often exceeding 20 years without losing capacity. Add in their safety, cleanliness and noncorrosive nature, and it’s clear that flow batteries can play an integral role in enabling renewable energy adoption.
What is a flow battery?
Imagine a rechargeable battery that can be scaled up to store large amounts of power for the grid — that’s exactly what flow batteries bring to the table. Traditional rechargeable batteries utilize solid anodes and cathodes in tandem with liquid electrolytes to transfer ions, allowing them to produce power and recharge when plugged in. Flow batteries have a different approach to energy storage capacity. Charge-carrying liquid electrolytes are housed in tanks, then circulated through an electrode assembly called a stack, comprised of two electrodes and an ion-conducting membrane. During charging and discharging, they are pumped through the battery power stacks in a constant “flow.” The energy storage capacity of a flow battery is limited only to the size of the tanks used to store the electrolyte. By multiplying the number of tanks, the energy storage capacity from flow batteries could feasibly supply the vast quantities of power required to support the evolving power grid.
A diverse array of flow battery technologies has emerged. Vanadium redox flow batteries have been in use for grid support for several years. These batteries are brought to market by companies such as Sumitomo Electric Industries (Japan), VRB Energy (Canada), RedT Energy (U.K.) and SCHMID Group (Germany). Other companies are developing novel flow battery chemistries, such as zinc bromine at Primus Power and iron-flow by ESS Tech Inc. and ViZn Energy Systems, all based in the U.S. Efforts are underway at French company Kemiwatt, and U.S. company CMBlu Energy, to develop flow batteries with biodegradable electrolytes, and free of heavy metals, rare earths and precious metals.
It is possible that in the future, the storage services that tank terminals provide will include both fuel storage and electricity storage. This is an exciting time for the liquid terminals industry, with many possible pathways for growth in our shared energy future.
For more information, visit ilta.org.
