Energy Storage: The Necessary Link between Renewable Energy and the Grid

As global warming coupled with resource depletion becomes a greater concern, renewable energies, especially solar and wind, are gaining the spotlight as the ultimate energy source of the future. Currently, as most people are aware, there are limitations to renewable energies that make them less desirable – limitations such as high cost, quantity of generation, and unreliable energy output. The reason that the quantity and reliability of renewable energy generation is important is because the renewables must generate this electricity to be sent to the grid in real time, meaning that the renewables must meet the current demand at any time while the production itself from these is highly variable, as seen in the form of wind power generation in Figure 1.


Figure 1. Wind Power Generation 

All in all, this sheds some light on the inherent issues behind renewable energies. Fortunately, there is the possibility of closing these gaps in energy production through energy storage, mostly electrochemically. The NREL created a report that essentially presented what impacts energy storage would have in regards to renewable electricity generation. The NREL categorizes energy storage into three different classes: power quality, bridging power, and energy management. These three only differ in the amount of time it takes to discharge the energy stored in the devices. Figure 2 shows most of the batteries and storage technologies used for larger energy storage along with their discharge times.


Figure 2. Devices used for large energy storage

Typically, batteries are very expensive for use in any industrial process. The two energy storage techniques with the largest storage capacity, compressed air and pumped hydro, use similar techniques in that they both force air or water to a higher energy level and then run a turbine to get the energy back out of the substance. Both, however, require specific geological scenarios to be effectively economical without having to recreate ideal settings. Notice that neither of these are electrochemical storage devices. Because of the need for energy storage for renewables, NREL has seen a dramatic increase in energy storage research since the 1970s.

One emerging electrochemical storage device that came out of research is something called the liquid battery, created in Dr. Donald Sadoway’s lab at MIT. Sadoway and a post-doc created a company, now known as Ambri, to further research with the hopes of commercialization. As seen in Sadoway’s TED talk, the liquid battery would be made out of common metals, making it economical, and has proven to be scalable to meet energy capacity needs.


Figure 3. The simplified liquid battery

If they can pull this off, it would essentially revolutionize the argument for renewables.

What is your experience with energy storage techniques? Would better energy storage make us turn to renewable energy faster? Could energy storage benefit other industries? Have you ever heard of the Liquid Battery? What do you think the consequences would be if Ambri succeeds in creating an affordable, scalable energy storage device?