In my first article, I had mainly talked about wind power and wind turbines. And in this article, I decided to continue with how we can store this green energy. I will talk about Energy Storage System.
We know that wind will not be continuous. It is unpredictable. This will influence on usage and quality of energy. And also, electricity is consumed at the same time as it is generated. We need to supply adequate amount of energy to meet varying demand. Therefore, we need to find a solution about the imbalance between supply and demand of the energy.
The solution about this is to build an energy storage system. There are various ways to store the energy. The table shown below demonstrates these ways.
From these 9 main storage systems, I will explain the Pumped Hydro Storage system (PHS). PHS systems are not a new vision in Renewable energy field. It has a very basic idea. The system uses two water reservoirs at different elevations to pump water during off- peak hours from the lower to the upper reservoir(charging). When required, the water flows back from the upper to the lower reservoir, powering a turbine with a generator to produce electricity (discharging). If we combine this system with wind turbine farms. We can get the energy for the pumps that will send back the water to higher reservoir from the wind farms. Also, wind turbines can send the surplus energy to the city. Additionally, we can generate electricity while we are pumping the water to higher reservoir with additional water turbines as shown in the figure. Therefore, we can improve our efficiency up to 95%. This is a remarkable value.
The theory behind the system is quite simple:
Potential Energy = Mass * Gravitational Constant * Height.
Potential energy in the upper reservoir turns into electricity at the water turbines.
Image source: Flickr