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Batteries role in stable energy supply and their storage

Balancing power supply and demand is always a complex process. When large volumes of renewables such as solar PV, wind and tidal energy, which can change abruptly with weather conditions, are integrated into the grid, this balancing process becomes even more difficult.

Energy storage can be a valuable resource for the power system in maximising the efficient use of this resource, and add flexibility for electric utilities. Effective energy storage can match total generation to total load precisely on a second by second basis. It can load-follow, adjusting to changes in wind and solar input over short or long time spans, as well as compensating for longterm changes. While fossil plants may take 10 minutes or more to come online, and will consume fuel even on "spinning reserve" standby, storing renewable energy for later use effectively produces no emissions.

 If you have some terrain resp. altitude difference and some water in the vicinity of the generation facility and cheap labor you will be better off pumping water to a reservoir for energy storage. Pump storage is not particularly efficient unless you are talking about MWs.

Ultracapacitors (or supercapacitors) store energy electrostatically by polarising an electrolyte, rather than storing it chemically as in a battery. Ultracapacitors have a lower energy density but a higher power density than standard batteries: they store less energy (around 25 times less than a similarly sized li-ion battery) but can be charged and discharged more rapidly. Although ultracapacitors have been around since the 1960s, they are relatively expensive and only recently began being manufactured in sufficient quantities to become cost-competitive. Ultracapacitors have applications in 'energy smoothing', momentary-load devices, vehicle energy storage, and smaller applications like home solar energy systems where extremely fast charging is a valuable feature.

Batteries have their uses. They are relatively inexpensive, relatively easy to maintain, but if your requirement is a constant load such as database centers or factories, then batteries are not valid UPS sources. If you only need occasional power, then batteries are ok.

Invented in 1859, lead-acid batteries use a liquid electrolyte and are still in common use. They store rather small volumes of energy but are reliable and, above all, cheap. In renewable energy systems multiple deep-cycle lead-acid (DCLA) batteries, which provide a steady current over a long time period, are connected together to form a battery bank.

Several types of batteries are used for large-scale energy storage. All consist of electrochemical cells though no single cell type is suitable for all applications.

In a dry cell battery, the electrolytes are contained in a low-moisture paste. Lithium-ion (li-ion) batteries in particular are the subject of much interest as they have a high energy density, and larger-scale production due to emerging electric vehicle applications is expected to bring down their cost significantly.

Lead acid is the old standby with a proven track record though and is the most used option. Lead acid battery is the popular one that people are using in solar system. Of course, Li-ion or LiFePO4 (and others) battery can be used as well. At this moment, however, performance-price ratio wise, lead acid battery is the best one now. Even in lead acid battery, there are still different technologies. tubular one is like normal flooded lead acid battery, which requires a battery maintenance every 6-8 months. And this battery is also quite popular in India. It's cheap comparing with Gel and AGM lead acid battery. Gel and AGM batteries are maintenance free during the life time. with better performance on deep discharge. If you only have low power consumers you might try lead acid, lithium might be to expensive and your facility to small for flow batteries

Check into Lithium Iron Phosphate batteries. Less impact on the environment (Do not contain Mercury and any heavy metal that do harm to enviromental and human beings).

At today's situation LiFePO4 is a good option. More expensive initially but more cost effective over its life. With LIFEPO4 you would have more cycles but also calendaric lifespan and temperature problems, so really a lot depends on the circumstance. I would also think in alternatives like potential energy if feasible.  LiFePO4 batteries can handle wide working temperature (-20C--60 C) much better than other. Long-lasting technology: lithium-ion batteries last three times longer than lead-acid batteries.
The advantage of lithium-ion batteries compared to lead-acid batteries is their greater storage capacity and energy density along with low weight and, above all, their long life.The high peaks and extreme loads placed on the accumulator would cause lead-acid batteries to quickly run down. A typical lead-acid battery has a maximum life of 2,000 cycles, In contrast, lithium-ion batteries last around 7,000 complete cycles. For a typical household this would represent more than 20 years - as long as the solar module itself. Lithium-ion batteries are also 50 to 80 per cent less likely to self-discharge and have much higher cycle efficiency, meaning fewer losses and more output for the user."

Lithium batteries. Flat plate (automotive) wet cells are rated for C20 discharge. Tubular (traction) batteries are rated for C10 discharge but can be discharged at higher rate, but the effective capacity decreases. However, LiPO4 batteries can be charged and discharged at C3 and even C1 rate and the loss of capacity is much lower. They can also be discharged down to 80% without significant loss of life and can operate at higher temperatures. They have a flatter characteristics compared to lead acid.

One technology that is now attracting considerable interest is large-scale battery storage.

Vanadium Redox Batteries (VRBs) are a particularly clean technology, with high availability and a long lifecycle. Their energy density is rather low - about 40 Wh per kilogram - though recent research indicates that a modified electrolyte solution produces a 70 percent improvement in energy density. Vanadium prices are volatile, though, with the increased demand for battery use likely to stress supply.

Flow batteries are emerging energy storage devices that can serve many purposes in energy delivery systems. They can respond within milliseconds and deliver significant quantities of power. They operate much like a conventional battery, storing and releasing energy through a reversible electrochemical reaction with an almost unlimited number of cycles. The active chemicals are stored in external tanks, and when in use are continuously pumped in a circuit between the reactor and tanks. The great advantage is that electrical storage capacity is limited only by the capacity of the tanks. Flow batteries have existed for some time, but have used liquids with very low energy density (the amount of energy that can be stored in a given volume). Because of this, existing flow batteries take up much more space than fuel cells and require rapid pumping of their fluid, further reducing their efficiency. 

Molten salt batteries (or liquid sodium batteries) offer both high energy density and high power density. Operating temperatures of 400-700∞C, however, bring management and safety issues, and place stringent requirements on the battery components.

Researchers at Case Western Reserve University are using iron to create a scalable energy storage system that can service a single home or an entire community. Robert Savinell, professor of chemical engineering at Case Western, calls it the rustbelt battery. Since the cost of iron is as little as 1 percent of that of vanadium, the iron-based battery is estimated to cost US$30/kWh, well below a $100/kWh goal set by Sandia National Laboratories. A large-scale 20-MWh iron-based flow battery would require two storage tanks of about 250,000 gallons (950 m3), and could supply the power needs of 650 homes for a day.

Spectrum spread sheet of different lamp families

http://www.ngdc.noaa.gov/dmsp/spectra.html 

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