Types of Energy Storage
In this post I am going to talk about Energy Storage. When you think of energy storage, I’m sure batteries are one of the first things that come to mind, but there are multiple ways to store energy. Let’s go over those different ways.
In terms of the Energy Pyramid, I would group Energy Storage at the top of the pyramid with energy generation because sizing the battery would come after or along with Energy Generation depending on the application.
If you need even further background, check out the first link below to learn what is Demand and Consumption. The second explains where in the Carbon Life Cycle the Energy Pyramid targets. The third, fourth, and fifth links go over the lower levels of the Energy Pyramid.
III. Energy Pyramid: Introduction & Conservation
IV. Energy Pyramid: Energy Efficiency
Batteries – we are all familiar with batteries, these are the things that were never included with the toy, banging them out of the TV remote when they die, do I put them in the garbage or recycle?, what are the little silver circle ones called? There are a handful of different types of batteries but the science around how they work remains relatively the same. It’s a chemical process between a positive and negatively charged substance. The differences in the batteries are the chemical types.
Thermal Storage – there are two major thermal energy storage systems, ice and water.
Ice – Ice Storage is used along with a chiller, so you are essentially saving energy by storing ice that can be used to cool your building instead of running the chiller to cool your building. During off peak times the chiller is run to build up ice in special tanks, then during peak hours, only the pumps are used to run refrigerant through the ice to be cooled instead of through the chiller system.
Water – in a similar fashion instead of using ice, you can use a stratified water tank. If you have ever swam in a lake or non-heated pool, you’ll notice that the water is colder the deeper down you go, that’s called stratification, there is a separation in temperature between the top and bottom layer of water. Similarly to the ice tanks, chillers will cool water and store it in a tank, during peak ours the building can than use that pre-cooled water to cool the building instead of using the chillers. The return warm water is returned back into the tank and remains on the top. Often times a diaphragm in the tank is used to further separate the warm and cold water and increase efficiency.
Potential (Gravitational) Energy – In my last post about renewable energy I mentioned that rivers and dams are used to generate electricity. Well, what if you make your own river, so to speak? During off hours, pumps are used to carry water to the top of a hill, so during peak hours the water can run down the hill, converting to kinetic energy, which runs generators to create electricity.
At this point, I think you may be seeing a trend happening here.
Compressed Air – compressors are used to compress air into underground tanks during off peak hours, or by using renewables. At which point the air can be accessed at any time to run the turbines on the generators to create electricity.
Kinetic Energy (Flywheels) – This is something I learned about while writing this article, flywheels. I was familiar with them only in terms of a car but I hadn’t realize they are being considered for larger scale applications as well. How does a flywheel store kinetic energy? A generator is a motor running in reverse, or vice versa. A generator converts mechanical energy into electricity and a motor converts electricity into mechanical energy. A Flywheel is a disk with significant mass attached to the mechanical end of the motor/generator. Friction and drag are drastically reduced on the flywheel, it may be in a vacuum and it has very well manufactured ball bearings. Then, during off peak hours, or with renewables, electricity runs the motor to spin the flywheel at very high speeds. The flywheel remains spinning until electricity is needed. Once the energy is required, friction is applied from the generator and the mechanical spinning force from the flywheel creates electricity!
Okay I learned SO much in this post, I didn’t know energy generation was even a real thing, compressed air is blowing my mind. (Wink) also had no idea that’s how flywheels worked!
Do you feel charged after learning all this!? (wink wink)