Energy Storage Systems for Photo Voltaic Installations

Energy storage systems (ESS) can significantly improve the optimum benefit of Photovoltaic (PV) Systems for self-consumption of electricity. Without ESS, the PV systems on private houses cover about 20 to 30% of their own electricity needs. The balance power generated is a surplus which is fed into the public grid at reasonably low tariffs. This situation can be easily modified by using ESS, wherein, self-consumption can be increased to at least around 40 to 60% with an intelligent energy management system.

With an energy storage system, self-consumption can be significantly increased and it is also possible to almost double it up to 80%. The task of the power storage is to temporarily store the power produced by the PV system and then make it available when it is needed, e.g. on days with little sunshine, at night or in the event of a power failure in emergency power mode.

Unarguably, the future of PV systems lies in systems with batteries/energy storage, as this can increase average self-consumption to around 80%. This results in potential energy cost savings for the system operator as a result of use of electricity at the place where it is generated, which gives a two sided benefit. Firstly, surplus energy need not be sold at low rate; and secondly electricity purchase from the public grid is minimized.

How the storage battery works...

A power storage device is like a larger battery that is charged and discharged like a rechargeable battery. During the day, once the house's electricity needs are covered, the battery (ESS) is charged with the electricity from the PV system. Only when the own requirements are covered and the ESS is fully charged, the excess electricity is fed into the grid. At night, when no electricity is being produced by the PV system, the stored electricity is drawn from the ESS.

Main reasons for purchasing an energy storage system:

-         - Self-consumption optimization

-         - Electricity cost savings

-         - Using clean and green self-produced electricity around the clock

-         - Independence from the power grid (emergency power in the event of a power failure)

Design of the ESS

When calculating the capacity of the ESS, it is important to ensure that the storage is efficiently assessed and utilized in order to avoid excessive investment costs. At the same time, the memory should not be designed too small, so that sufficient power reserves are available at all times when needed. If it turns out in the course of operation that the battery capacity selected is too small, this can be retrofitted to most systems.

As I have read online, a rough thumb rule is suitable to get around 60% self-consumption, is to consider the annual electricity requirement, the electricity generation of the PV system and the storage capacity in a 1:1:1 ratio.

Furthermore, it is advisable to determine the electricity requirements in the household as precisely as possible, so that a suitable ESS capacity can be decided. Power consumption of past few years is ideal for planning as a basis or a load profile analysis for more precise energy requirements during the day or night.

With fast developing and improving technology, the calculations are intelligently handled with latest softwares to get optimum results with PV Systems and Energy Storage Systems. I look forward to further advancement in technology to yield more efficient Energy storage systems so that the Photo Voltaic installations can be utilized to their optimal value.

Sources and  References

https://www.schrack.at/

https://en.reset.org/energy-storage-systems-linchpin-energy-transition-07202021/

Image Source

https://i.ytimg.com/vi/UgLLW5ro0pw/maxresdefault.jpg