Choosing the Right Energy Storage Solution

With so many energy storage solutions being developed what is the right storage mix?
Published: Thu 30 Jan 2014

The installation of energy storage technology is on the rise. Currently, installed technologies exceed 125 GW worldwide. This is according to the Electricity Advisory Committee's report "Energy Storage Activities in the United States Electricity Grid."

Today, the most popular storage systems for bulk storage include pumped hydro and compressed air systems. This is according to data from the Electricity Storage Association.

Distributed energy storage offers flexibility

While a distributed energy system is more costly per KW than a bulk storage system, it provides more flexibility. Although more expensive per kilowatt than a bulk storage system, a distributed energy system provides more flexibility. With a distributed energy storage network, a utility can focus on specific areas, storing and providing energy for immediate use, such as in heavy commercial or population-dense areas. This will allow for more efficiency when it comes to the integration of renewables.

Energy storage is a mix

It is essential that utilities develop a clear profile of the storage application. This will help the utility to choose the appropriate energy storage solution. The utility should address the following before a final decision is made:

  • Performance-The utility should start off by determining whether it needs to generate power, store energy or both. Other performance requirements such as increasing reliability, enhancing power quality, and integrating renewables should also be considered. The utility needs to have a good understanding as to how much capacity is required and what the reaction time should be.

  • Period (life cycle)- Utilities should opt for the battery with a life cycle which is most appropriate for its needs. The utility may not need to spend money unnecessarily on a battery with an extremely long life cycle.Cost-efficiency is the key word here.

Three factors impact cycle life and must be considered:

  1. Depth of discharge- There is a direct correlation between the depth of discharge and the number of charge and discharge cycles a battery can perform.

  2. Temperature- This can have a major effect on a battery’s ability to operate effectively.

  3. Charge- Charging methods vary so the management thereof is key since overcharging could have a negative effect.

Risk Management-With an increase in new technologies, safety risks must be considered. Storing energy involves understanding what to do when there is a failure, how to control it and how to avoid a potential crisis.

Power- High-energy, high-cycling solutions may not be necessary. Energy density is attractive, but it’s costly and is normally only needed when space is limited. For Instance, lead acid batteries might deliver the necessary performance requirements at greater savings than other high-energy storage solutions.

Price- Cost is a major deciding factor. Before utilities explore new technology options, it may serve them to use familiar technologies which may prove to be more cost-efficient than newer ones.

Maintenance-Maintenance requirements differ based on the type of technology, amount of run time and physical environment.

Choosing a system integrator

When it comes to building a customised solution, some utilities will partner with a systems supplier and integrator.

Utilities should be careful when choosing a supplier as some will only specialise in one technology. Utilities should rather opt for a supplier that has an established line of proven storage chemistries. These suppliers will be able to make recommendations on the merits of each technology instead of promoting one that probably won’t be appropriate.

Utilities should also rather opt for a partner with a firm financial history to ensure long-term security of supply.

The key is to choose the right solution and partner for the application at hand. New solutions may look impressive but familiar technologies should not be overlooked as they often offer proven, cost-effective results.