Renewable energy storage costs may soon become more competitive

Researchers at the Massachusetts Institute of Technology (MIT) have investigated how much the cost of energy storage must fall before the use of renewable energy can reach its full potential. The experts estimated the target costs that would allow solar and wind energy to compete with other on-demand energy sources, and examined which types of technology could be used to help reach these targets. 

“One of the core sources of uncertainty in the debate about how much renewable energy can contribute to the deep decarbonization of electricity is the question of how much energy storage can be improved,” explained study senior author Professor Jessika Trancik. 

“Different assumptions about the cost of energy storage underlie significant disagreements between a number of assessments, but little was known about what costs would actually be competitive and how these costs compare to the storage technologies currently being developed. So, we decided to address this issue head on.”

“Quantifying cost targets for energy storage required a new piece of insight about how patterns of the renewable energy supply, and fluctuations in this supply, compared to electricity demand profiles. Large but infrequent solar and wind shortage events are critical in determining how much storage is needed for renewables to reliably meet demand, and it’s important to understand the characteristics of these events.”

The study was focused on the costs of using storage together with wind and solar energy to reliably supply various outputs for twenty years. Next, the team modeled the target costs that would make these renewable options competitive.

The researchers also analyzed the characteristics that distinguish various storage options. For example, some technologies are designed to store large quantities of energy inexpensively, but with a slower output. Other technologies are designed to store smaller amounts of energy that can be discharged at high speeds. 

The study revealed that technologies with energy storage capacity costs below $20/kWh could enable cost-competitive power that is consistently available over a twenty-year period. Professor Trancik said that it is critical to reduce the costs of the materials and manufacturing that contribute to the cost of the storage energy capacity. 

“The numerical target we estimate, which varies with location, could mean a 90 percent drop in storage costs relative to today’s technologies. It’s a large drop but some technologies do tend to improve a lot, as we’ve seen in the case of solar panels, for example.’

“However, and importantly, there is another factor that could raise this target considerably and allow more expensive technologies to cost-competitively store renewable energy, which is to use supplemental technologies for a small percent of the time,” explained Professor Trancik.

The team is now exploring options for low-cost and low-carbon supplemental technologies. 

The study is published in the journal Joule.

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By Chrissy Sexton, Earth.com Staff Writer

Paid for by Earth.com

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