The research shows that the application of energy storage technology with longer duration of continuous discharge may be multifaceted, because different energy storage technologies will play their own role in the application of grid side and user side.

Jin Noh, policy director of the California energy storage alliance, said at the 2021 online meeting of the U.S. energy storage summit hosted by solar media, he believes that the energy density per square kilometer will be a special consideration.

"One thing that may not be valued as a grid product is the energy density of every square kilometer of land," Noh said. Especially when considering these elastic applications, we cannot over deploy solar power generation facilities or energy storage systems to provide this flexibility. Or in a local capacity constrained area such as the Los Angeles basin, where land is not only expensive, but also when considering how to use limited land and have to store more energy, I think this value may be in terms of energy storage. But I think that's what people might ignore. At a higher level, or in the grid planning model. "

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Experts believe that the long-term storage system can last more than six hours, which may help to deploy renewable energy power generation facilities in areas with limited land.

Erik Stokes, director of the energy deployment Office of the California Energy Commission, said that in areas such as California, some emerging energy storage technologies, such as the zinc battery storage system on the user side, are facing opportunities, which are increasingly affected by forest fires and public safety blackouts (PSPS).


With the occurrence of these events, people pay more and more attention to micro grid and energy storage system, and grid elasticity has become a problem that many people pay attention to.


"Many customers need energy storage solutions that last longer, especially those who can't afford 10 to 14 hours of power outages, which lithium-ion battery storage systems may not be able to meet," Stokes said


He highlighted regulatory reforms made by the California Utility Commission this year to ensure that telecom companies have 72 hours of standby power during blackouts. In the past few years, many telecommunication towers have been damaged in forest fires, which has affected communication between the affected areas.


Compared with diesel generators with serious air pollution, long-term energy storage system which can provide more than 72 hours of continuous discharge time will obtain important revenue sources.


The team also included Monica Padilla, director of power resources at Silicon Valley clean energy, Julia prochnik, executive director of California long-term energy storage association, and Jaime Vega Marcos, managing director of E22 energy storage solutions. They say three long-term energy storage systems may compete for commercial feasibility in the coming years.


However, the long-term energy storage technology is widely used, such as pumping storage facilities, flywheel energy storage, gravity energy storage system, thermal energy storage and green hydrogen, which makes it difficult to choose a single energy storage technology because they can not solve the overall problems. For example, energy storage technologies that provide longer duration of discharge during a public safety outage (PSPS) are unlikely to be those that meet seasonal requirements.


"I think long term storage systems can be deployed locally, such as pumping storage facilities and zinc batteries," prochnik added. Different types of liquid air storage systems or green hydrogen can replace fossil fuel power plants. And this plug and play deployment model will bring more benefits to the U.S. states. "


The panel agreed that more support was still needed to make some energy storage technologies stand out, not only to take into account the current value proposition, but also to the needs of power systems in the coming decades. This is in line with the comments of Dr. Imre gyuk, head of energy storage research, Department of energy. He said the commercial operation problems faced by long-term energy storage technologies need to be addressed to help the United States achieve its carbon removal goals.


Paddilla stressed that the area of long-term energy storage requires more investment. In policy driven areas like California, long-term storage system deployment plans can play an important role.