Context: As per a study by Climate Trends and JMK Research and Analytics, a hybrid renewable energy system along with battery storage will be cheaper than coal power in Tamil Nadu. Additionally, it will reduce curtailment of renewable energy.

Key Points by the study

• Battery based system can address the issue of power curtailment.
• Reduce the heavy losses to the renewable power developers.
• The above highlights the need to understand about various types of energy storage systems.

Types of Energy Storage Systems

The most popular battery technologies for energy storage

Flooded lead-acid batteries

• Flooded lead-acid batteries contain an electrolyte that is free to move around in the battery encasement.
• When charged, the battery acid and lead plates react to store electricity.

Valve regulated lead acid batteries (VRLA)

• These are really "recombinant" batteries, which means that the oxygen evolved at the positive plates will largely recombine with the hydrogen ready to evolve on the negative plates, creating water and preventing water loss.

Lithium-ion batteries.

About Lithium-ion batteries

• A lithium-ion (Li-ion) battery is an advanced battery technology that uses lithium ions as a key component of its electrochemistry.
• During a discharge cycle, the lithium ions move from the anode and pass through the electrolyte until they reach the cathode.
• The most common combination for electrodes is that of lithium cobalt oxide (cathode) and graphite (anode).
• Li-ion batteries typically use ether as an electrolyte.

Advantages

• Having a very high voltage and charge storage per unit mass and unit volume.
• It has highest energy density among other batteries.
• Low maintenance.
• Don’t require scheduled cycling to maintain their battery life.
• No memory effect.
• A detrimental process where repeated partial discharge/charge cycles can cause a battery to ‘remember’ a lower capacity.
• Have low self-discharge rate.
• Don’t contain toxic cadmium.

Disadvantages

• Tendency to overheat.
• Can be damaged at high voltages.
• They are subject to the ageing meaning there is a drop capacity in time.
• Expensive.