Energy Storage: Potential Downfalls
lubi solar       July 9, 2019
Rooftop solar technology has seen good acceptance, globally. People have shown encouraging response to the marketing proposition and seem to be understanding the long standing cost benefits of installing solar power plants to decrease the electricity costs in the long run.
This has opened up new avenues for energy storage technologies, wherein the dependence on grid power may be decreased to the bare minimum or even completely eliminated.
Energy storage technology primarily revolves around harvesting energy in a storable form and using it later with the help of a usable conversion.
In the rooftop solar plants, the solar energy gets produced in the earlier half of the day, and needs to be utilized immediately. In some cases, especially households, the day utility of power may be very less compared to night.
This excess energy can be stored to be utilized later, thereby minimizing grid dependence. This type of captive utility can provide access to virtually free power after covering the capital installation costs.
Power storage can generally take the form of electric batteries, compressed air, pumped water, rotating flywheels or electrolytic reactions. But generally, in the solar context, it is electric batteries. Power storage technology like electric batteries allows to optimize the existing generation and transmission infrastructure while preventing expensive upgrades.
It also helps manage irregularities like power fluctuations, improving power quality and reliability thereby aiding transition to renewable technologies like solar.
But as the circle comes through, we also need to deal with certain shortcomings of these storage technologies. We may focus here on the electric storage in batteries.
- High Capital Cost:
Considering the size of solar rooftop projects, the cost of storage backup for the power is very high. Sometimes it almost equals the operating system cost, making it nonsensical to invest in storage systems considering ROI on the system.
- Complexity of Design:
Designing a storage system for a power generating unit is a complex and tedious process. It is very important to optimize the backup for the rated requirement with adequate cable sizing and protection. In case of battery unit, it is also critical to house the unit properly away from heat and humidity to optimize performance and prevent thermal runaways.
- Increased Maintenance :
Generally battery system require extensive maintenance plans and are costly. It is very critical to preventive maintain battery systems for performance and safety reasons.
Electric batteries come with limited charge/discharge cycles. A charge/discharge cycle is commonly understood as the complete discharge of a fully charges battery with subsequent recharge. Manufacturers generally use 80% depth-of-discharge formula to rate batteries, thereby disallowing complete discharge of batteries.
This practice allows to increase the lifespan of average battery systems. The general lifespan of solar battery is between 5-15 years. That means, in the lifespan of the solar system, the battery bank needs to be changed at-least once. This is a cost adder to the capital cost and needs to be estimated while considering ROI.