Batteries and the Power Grid - What will the Future bring?
The need for storing energy has never been more important than it is today. While the world’s demand for electricity continues to increase the means of generating it is largely inefficient and in some cases unfriendly to the environment.
As electricity is either consumed or lost it requires utility companies to constantly alter the amount of electricity they produce to match demand. For instance on a hot summer weekday when businesses and air conditioners are running full power electric companies have to increase the amount electricity they generate. While on a temperate weekend when power consumption is low electric companies reduce the amount of energy they generate. This is like an automobile without a transmission, while altering the speed of the car can be accomplished by increasing or decreasing the motor’s RPM it is largely inefficient. Though when a transmission is added and the engine is run at its optimal RPM, does the car provide the best MPG.
The same is true by adding a battery storage system to the electrical grid. Instead of running a generator outside of its optimal level run it at its most efficient rate and then let the battery system supply or store the extra electricity. This peak shaving load leveling idea is nothing new but the batteries that make it viable are.
For a battery to make sense it requires a technology that offers a low cost per cycle, long calendar & cycle life, minimal maintenance, ability to charge & discharge at the necessary rates without rest, and is extremely safe. Here is a comparison of how some battery chemistries compare.
While cell chemistry selection is very important in these systems so is the Battery Management System (BMS). As lithium cells are very efficient and powerful the BMS insures they are protected from abusive situations like overvoltage, undervoltage, overcurrent, and extreme thermals. In addition to system protection a high quality BMS should include cell balancing which keep all of the cells within a pack at an equal state of charge. While an application will dictate which type of cell balancing system is the most ideal, a good balancing system will supply both superior cycle life and calendar life.
Like most products not all cell and BMS manufacturers provide the same performance and quality. As battery storage systems require high performance with upmost safety it is important to look beyond just initial price and determine if the performance over time and safety in relationship to price are acceptable. While initial low cost solutions are enticing performance and safety tradeoffs could prove to be most detrimental.
The benefit of adding a storage battery to the grid has hardly gone unnoticed as new and existing companies are putting tremendous investments into making it a reality. One such company is Tesla who has made quite a buzz with the introduction of their new storage battery systems. As their lithium battery systems are designed to charge from solar panels or when the utility rates are low and supply power when needed or when rates are high they could revolutionize the electrical utility market. Their end user approach with enough adoption could dramatically change the way electric companies conduct their business.
Only time will tell how the market ultimately evolves though one thing is clear batteries are going to be an integral part of solving much of the world’s power issues.