shortcoming of grid-tied systems: that they must disconnect from the grid when the grid is not present, for safety reasons per the UL 1741 standard. During the protracted power outages following Sandy, many hundreds of kilowatts of solar electricity were literally left “up on the roof,” unusable to the storm-
affected residents struggling down below.
What all these renewable energy challenges have in common is that energy storage is their solution, and that adoption of the microgrid concept of storing electricity locally at the point of generation and conversion is the most practical means of employing storage technology. If Californian, Hawaiian and German solar users stored their generated surpluses, they could draw on that reserve instead of drawing from the grid when renewable sources are not available—increasing both their energy independence and the stability of the grid, which would not have to absorb large fluctuations. And if all those solarized New Jersey residents had back-up energy storage connected to their grid-tied systems, they could have effectively lived off-grid during the time it took to return to normal after Superstorm Sandy.
Energy storage comes of age
This is why, after many decades of separate development for their respective regions and applications, the economics of grid-tied solar are being connected to the independence and security of off-grid methods in hybrid designs engineered to deliver the best of both worlds. At their foundation is the ability to store electricity in a practical, safe and affordable manner. It’s for this reason that leading solar industry sources predict that the most rapid growth will be in the energy storage category. For the past year, storage has been the dominant story at solar expos and trade shows around the globe; and report after research report predicts triple-digit annual category growth as battery prices decline and installations soar.
In its “Top 10 Solar Market Predictions for 2014,**” IHS Research lists storage at the top, stating that “demand for PV energy storage systems is booming, with installations set to quadruple in 2014…to 753mW, up from 192mW in 2013.” For users and installers around the globe, being prepared to work with the renewable energy systems of tomorrow requires becoming an expert on energy storage today.
*The Wall Street Journal, “Europe’s Renewable Romance Fades,” 7-30-13
**Solar Industry magazine, December 2013
Common Batteries Used in Renewable Energy Storage
We have this abundant, limitless amount of energy potential we can harness in the sun, but how do we store it when we don’t need it? Where do we put it? How do we get it out of where we put it? To answer these questions means learning the basics of batteries.
We use batteries in our everyday lives and they play an important part in technology and its advancement. Every day a new technology, process improvement, methodology or chemical formula is discovered to push the battery industry forward. Specifically relating to renewable energy storage, the battery becomes an even more important factor.
What is a battery?
Simply stated, a reaction where chemical energy is converted to electricity. Technically, a container consisting of one or more cells, in which chemical energy is converted into electricity and used as a source of power. Batteries can be divided into two different market segments: Primary (non-rechargeable, such as alkaline AA batteries) and Secondary (rechargeable such as lead acid batteries).
There are ever-present standards today in renewable energy storage such as proven (Lead-Acid), growing (Lead-Acid-Carbon / Ni-Mh), and emerging (Li-Ion, Aqueous, Flow) technologies. It seems every day there is a new announcement on a breakthrough energy storage device that will be the end-all for all energy storage in renewables. While they all have their benefits and disadvantages to the other, essentially two chemistries have the most important role in renewable energy storage today.
OPTIMIZING PV SYSTEMS - PART 2: energy storage
Energy Storage eFeature | January 2015