There are many different ways in which you can store energy and this got me wandering about the options, efficiencies and the applications. Some of the applications are not always obvious, but a lot of different systems are used in engineering and in models.
Starting with the fundamental energy storage categories and sub-categories:
- Lead Acid Battery – a battery with electrodes of lead oxide and metallic lead that are separated by an electrolyte of sulphuric acid.
- Lithium Ion Rechargeable Battery – a rechargeable lithium ion battery lithium ions move from the negative electrode to the positive electrode during discharge, and back when charging.
- Nickel Metal Hydride Battery – rechargeable battery
- Fuel Cell – a device that converts the chemical energy obtained from a redox reaction directly into electrical energy. A fuel cell is a battery where reactants are supplied to the cell from an external source.
- Compressed air
- Flywheel – a flywheel stores rotational energy, in it’s simplest form as a spinning top.
- Hot water tank (steam boiler)
All of these have advantages, disadvantages, efficiencies and costs. In order though to do more calculations it is necessary to often size the system. So let’s stay with the model world and think about an application for a model where I need 750W peak (approximately 1 brake horsepower) and that I need to be able to deliver 250W of power continuously for 20 minutes, so that equates to ~83Wh of useable energy.
This will also allow us to plot and compare power versus energy storage capability.