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As solar panels, wind turbines and other forms of clean energy technologies continue to advance one key component continues to lag behind - the all-important battery. Without energy storage in the form of batteries, the clean energy created by these systems is very limited in its ability to provide energy when it is needed. Solar panels only produce power during the day and wind turbines only when the wind is blowing. The clean energy produced by our current systems is intermittent. Without cost effective and non-toxic storage systems our national electric grid will never be able to really capitalize on the integration of clean energy technologies due to the fact that the power these technologies produce simply cannot be stored and released as needed. In fact, for every large scale solar or wind farm built there is always a coal or natural gas plant running to pick up the slack for when the wind stops or the sun doesn’t shine.

We need advanced storage systems, which as of yet, are unavailable; or available at a cost that would make clean energy technologies unaffordable and not able to be utilized on a national/global scale. Currently, the battery technologies for small-scale storage applications are Flooded Lead Acid, Sealed Lead Acid and Lithium Ion batteries. Lead Acid battery choices have been the standard for the last 50 years while Lithium Ion has emerged more recently.  

Lead Acid batteries, although an old technology, are the economical choice for providing power for smaller off the grid applications. Since their creation, not much has changed with the technology. They are heavy, corrosive, and extremely limited in their ability to provide reliable energy storage over the long term. Flooded Lead Acid batteries release toxic gasses as they charge and discharge and require regular maintenance in the form of watering and equalization charges. Typically these batteries should last as long as 15 years but without proper maintenance you can easily destroy a battery bank in just a few short years.


L16 Lead Acid Batteries in need of some maintenance!


Sealed Lead Acid batteries are a safer option for battery storage for numerous reasons. These batteries don’t off gas and being a sealed product means it is not possible to gain access to their corrosive electrolyte. They do not need watering or the regular maintenance associated with flooded batteries. Sealed batteries are also impervious to freezing which make them a great battery for installations in extreme conditions and remote telecom applications. Because of the many benefits, many renewable integrators (myself included) are using more sealed batteries in their system designs despite being twice as expensive per amp hour of capacity as flooded batteries. The benefits simply outweigh the costs.


Brand New Sealed Lead Acid Batteries


Lithium Ion battery technology is relatively new compared to the other options discussed. These batteries are currently the option of choice for the electronics industry.   Although commonly used in cell phones and computers, these batteries are still undergoing research and development to help them become more widely acceptable for powering larger applications. The extremely high cost of Lithium Ion batteries and their required specific battery management technology make their adaptation to home use still out of reach for most consumers at this time. There are many benefits to lithium Ion batteries. They do not require maintenance like lead acid batteries do. They are a sealed product so there is no chance of off gassing or exposure to corrosive electrolyte. These batteries like a less aggressive charging algorithm and can handle the daily charging and discharging associated with off grid applications. In fact, lithium Ion batteries are used extensively in the electric car industry giving users great performance with less weight per amp hour of capacity. If the technology to manage the charging and discharging of these batteries advances, there is a great chance a Lithium Ion battery bank will be the standard of future home backup systems.


The future looks promising for the battery storage industry with new technology emerging rapidly. One company called Aquion has developed a battery that use sodium ions from saltwater as their electrolyte. Their batteries are designed to power remote micro grids. These micro grids would provide power to areas without grid power. Aquion claims their batteries cost as much as traditional lead acid batteries but last twice as long. Redox Flow batteries are another battery storage system being tested. These batteries look like traditional batteries but act much differently. One example of their uniqueness is how they store their energy. Flow batteries store energy within their electrolyte rather than in lead plates (which is how traditional batteries work). One advantage to this kind of system is that the battery’s electrolyte can be completely removed and recharged while new electrolyte is put back in. This ability gives the battery an almost limitless lifespan. And finally, Tesla has been in the news recently hyping their home battery storage technology, in partnership with Solar City. What impact this will have on renewable energy system integration remains to be seen. One thing is clear however, battery technology of the future will change the way we use and store energy and is essential to helping integrate widespread use of renewable energies.