One long-standing problem with energy grids is that there are hourly, daily and seasonal variations in electrical demand. For example, electrical demand can double over the course of an August day in Jordan and the average daily load can vary by more than 25% between March and August.
The generation output of promising alternative energy sources such as solar, wind, hydroelectric and tidal power also fluctuates. Matching this variable supply with variable demand is a huge challenge for electricity producers.
The ability to shift grid capacity across long distances can help somewhat, but what we really need is a technology for efficiently storing excess electricity during times of oversupply and releasing it during times of high demand.
Pumped storage is one possible storage solution, water is pumped uphill to a reservoir during times of excess and released past hydroelectric generators during times of high demand. But this technology requires large amounts of water and a well-placed hill or mountain.
Chemical batteries are another possible grid storage solution. These are large scale versions of lead-acid car batteries, AA nickel-metal hydride batteries or the lithium batteries in laptops and iPhones. A typical iPhone battery stores about 5 Watt/hours of electricity, so Enstorage’s first Hbr battery deployment has approximately the same capacity as 20,000 iPhone batteries or 30,000 AA batteries.
One advantage of Enstorage’s hydrogen bromine flow battery is that the chemicals used are abundant and therefore relatively inexpensive.
Hydrogen can be extracted water and bromine is component of Dead Sea salt. Jordan and Israel already harvest bromine from Dead Sea salt evaporation pools. Bromine currently costs a little more than $5000 per ton. A second advantage is Enstorage’s proprietary conversion stack technology which can provide up to three times the energy density of existing grid storage batteries.
A third advantage of Enstorage’s Hydrogen Bromine flow battery has to do with the concept of a “flow battery.” Unlike ordinary household batteries, the liquid electrodes of flow batteries can be stored and external tanks and produce energy as they flow through the battery. This means the capacity can be increased simply by increasing the size of the storage tanks.