All Eyes on Energy Storage

Last month's total eclipse offered grid managers a taste of what it might be like to bring balance to the grid in a world where solar power is much more prevalent. Luckily, the dip in solar output did not lead to a significant disruption in supplies, because solar still accounts for less than 1 percent of the nation's electricity, a manageable sum to prepare for.

In a few short years, however, solar power's footprint will be much larger and more problematic for grid managers tasked with maintaining perfect balance between supply and demand.

Solar accounted for 30 percent of all new generation capacity in the first quarter of 2017. What's more, wind and solar will be used to produce a whopping 34 percent of the world's generation by 2040, according to a recent report from Bloomberg New Energy Finance.

Last month's eclipse magnified the challenges created by the ebb and flow of solar power. But, it also highlighted the tremendous value of another emerging technology, which, by most accounts, is on a road to mainstream use.

The outlook for energy storage continues to improve, giving utilities the confidence to add large-scale storage to their systems. The technology is no longer confined to a handful of states and is being adopted by power producers outside niche areas such as California and Ohio.

Last year, the U.S. added another 221 MW of utility-scale battery storage as the cost of those projects continued to drop. Worldwide, more than 1,300 MW of grid-connected storage was deployed in 2016, according to research from HIS Markit. The global annual growth rate is expected to rise to 4,700 MW by 2020 and to 8,800 MW by 2025. Additionally, prices for lithium-ion battery storage are expected to fall below $200 per kilowatt hour, and global storage capacity is projected grow from 4,000 MW today to 52,000 MW by 2025. The U.S. now has 565 MW of installed storage capacity, up 47 percent from last year.

Battery storage is still risky and expensive, and many utility executives remain cautious. For rapid scaling to occur nationwide, analysts say prices must continue to fall. For some utilities, battery storage is still not cost effective, despite progress on projects in California and elsewhere.

Two battery makers - Alevo and Aquion Energy - declared bankruptcy this year after struggling to achieve commercial production. Alevo attributed the bankruptcy to "significant production challenges" and "insufficient revenue to continue operations."

But the power sector may be forced to bear the cost, because it's plainly evident that energy storage will be fundamental in supporting a grid congested with variable power supplies.

Energy storage projects using rechargeable batteries will give grid managers the solutions they need to fill production gaps created by sharp fluctuations in wind and solar power. The ability to supply utility-scale power on demand will be key to ensuring reliability and achieving integration amid this renewable revolution.

Storing electricity on a large scale has long been pursued by electric utilities in hopes of using the power to cover periods of peak demand. After years of limited progress, several capable systems for storing large amounts of power have emerged from research and development efforts borne from new mandates for energy storage capacity and public demand for cleaner power supplies. Some grid-scale systems are viable now, while others are on the verge of viability.

Source: Power Engineering