As energy storage deployment grows across a variety of sectors and fuel sources, a team of researchers at the University of Michigan has published a set of 12 principles to help guide projects on the most sustainable path forward.
A main driver of the research is that energy storage can still have negative environmental consequences in certain grid applications, particularly in producing batteries. The principles provide a “qualitative framework” as entities deploy and operate energy storage, researchers say, whether it’s a lithium-ion battery or a large utility-scale pumped storage facility.
“These are guidelines or principles you can take into account to make sure there is the least environmental impact in terms of optimizing solutions,” said Maryam Arbabzadeh, a graduate assistant at U-M’s School of Natural Resources and Environment. She is also author of “Twelve Principles for Green Energy Storage in Grid Applications,” which was recently published in Environmental Science and Technology.
Arbabzadeh said the study is published with “very good timing as utilization of energy storage is growing rapidly.”
The principles are split into three categories and were inspired by green chemistry and engineering principles. The researchers distinguish between “capacity applications” — which could displace the need for new transmission and distribution — and “energy applications,” which would reduce curtailment from renewable sources.
The first category targets the grid application of energy storage and is geared toward utilities, Arbabzadeh said. The first principle in this section is to “charge clean and displace dirty” energy.
“It is very crucial to consider the marginal units that are dispatched to charge the energy storage system and the marginal units that are displaced by energy storage within an interconnected grid,” the researchers write.
Another principle in this category cautions against “oversizing” energy storage systems. For example, if a battery is used for integrating wind into the grid but there isn’t enough generation to fully charge the battery, “You’re just increasing the environmental impacts because producing the battery has some emissions,” Arbabzadeh said. “People usually don’t think about the production that’s going into making the battery.”
The second category targets storage operators and maintenance, specifically encouraging systems with optimal service life and getting maximum round-trip efficiency.
The final category targets designers while in the early stages of development and minimizing the use of non-renewable and hazardous materials.
“You need to make separate categories for each of these audiences,” Arbabzadeh said.
Levi Thompson, a U-M professor of chemical and mechanical engineering and co-author of the report, said the bottom line question is: Will storage technology help with enhancing sustainability, regardless of whether it’s a fossil or renewable fuel that’s being stored?
“That’s really what this effort and overall project is about,” Thompson said. “Everyone is enthusiastic about adding storage to the mix, but if you add the wrong type, the window where is doesn’t make sense is narrow,” he added.
The researchers write: “Not only do the grid benefits vary greatly across technologies, the design, manufacturing, deployment, and operation of energy storage systems may lead to significantly different environmental impacts.
“Indeed, the environmental outcomes of integrating energy storage within the power grid depend on the grid application, the existing generators, and the demand profile.”
Thompson said the researchers were also careful not to “throw darts” and single out one particular technology in which using storage doesn’t make sense.
Still, the main barrier to widespread storage adoption at this point is cost, Thompson said.
“If it costs too much to deploy, it’s just not going to be done,” he said.