Researchers from Stanford University have determined that while storing surplus energy generated by solar farms in grid scale batteries is viable in terms of energetic cost; it may not be the same case for wind power.
The Stanford Global Climate and Energy Project (GCEP) researchers set out to calculate the overall energetic cost required to build and operate grid scale battery storage based on five battery types – lead-acid, lithium-ion, sodium-sulfur, vanadium-redox and zinc-bromine.
While it was “energetically favorable,” to construct facilities for solar farms, the scientists found curtailing wind power reduces the energy return on investment by 10 percent; but battery storage resulted in even greater reductions – from about 20 – 50 percent depending on the battery chemistry used.
“You wouldn’t spend a $100 on a safe to store a $10 watch,” said GCEP postdoctoral scholar Michael Dale, a co-author of the study. “Likewise, it’s not sensible to build energetically expensive batteries for an energetically cheap resource like wind, but it does make sense for photovoltaic systems, which require lots of energy to produce.”
The researchers calculated how much energy is used over the full life-cycle of each battery technology – from mining the raw materials to the installation and subsequent maintenance.
While the battery technologies studied may not be attractive for wind, there are other options; such as pumped hydro or using the excess power for other applications including charging a fleet of electric vehicles.
“Energy return on investment is one of those metrics that sheds light on potential roadblocks,” said co-author Sally Benson, the director of GCEP. “Hopefully this study will provide a performance target to guide future research on grid-scale energy storage.”
The Global Climate and Energy Project’s mission is to conduct fundamental research on technologies that will permit the development of global energy systems with significantly lower greenhouse gas emissions.
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