In a myth-busting revelation, a study has found out that storing solar energy for night time use actually increases both energy consumption and emissions compared with sending excess solar energy directly to the utility grid.
In a paper published in Nature Energy, researchers assessed the trade-offs of adding home energy storage to households with existing solar panels, shedding light on the benefits and drawbacks of adding storage considering today's full energy grid mix.
According to research from the Cockrell School of Engineering at The University of Texas at Austin, homes with solar panels do not require on-site storage to reap the biggest economic and environmental benefits of solar energy.
According to the Solar Energy Industry Association, the number of rooftop solar installations grew to more than 1 million U.S. households in 2016.
There is a growing interest in using energy storage to capture solar energy to reduce reliance on traditional utilities. But for now, few homes have on-site storage to hold their solar energy for later use in the home.
Michael Webber said." The good news is that storage isn't required to make solar panels useful or cost-effective. This also counters the prevailing myth that storage is needed to integrate distributed solar power just because it doesn't produce energy at night".
The researchers found that storing solar energy for nighttime use increases a household's annual energy consumption, in comparison with using solar panels without storage, because storage consumes some energy every time it charges and discharges. The researchers estimated that adding energy storage to a household with solar panels increases its annual energy consumption by about 324 to 591 kilowatt-hours.
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Webber and Robert Fares analyzed the impact of home energy storage using electricity data from almost 100 Texas households that are part of a smart grid test bed managed by Pecan Street Inc., a renewable energy and smart technology company housed at UT Austin.
If a homeowner is seeking to reduce his or her environmental footprint, adding storage would not make the household more green, but it shouldn't be dismissed either, the researchers said.
"Solar combined with storage is still a lot cleaner than having no solar at all," Fares said.
In short, the analysis showed that storing solar energy today offers fewer environmental benefits than just sending it straight to the grid, because the energy lost to storage inefficiencies is ultimately made up with fossil-fuel electricity from the grid.