Energy Storage: What It Is and How It Works

Sun, wind, and water are the top three main sources of renewable energy, but how can we use these energy sources if the sun doesn’t shine, the wind doesn’t blow and the water doesn’t flow?

This is exactly the reason why countries are focusing so much on the energy storage this time. But energy storage doesn’t only stores energy, it also have a few more benefits like help grid-managing entities flatten out the peaks and troughs in demand, regulate voltage and frequency, helping it avoid upgrading or building expensive new infrastructure, help keep critical services like police, shelter and medical care working in the event of an emergency and most importantly it helps avoid blackouts, and bring the grid online faster when a blackout does happen.

But having energy storage is not that easy for it is really expensive. Industry observers have noted that research efforts and increasing production capacity are helping the prices of batteries come down, but they are still relatively scarce compared with the size of the country’s generation capacity.

Nevertheless, utilities are now beginning to look toward the idea of large-scale batteries. More established technology is pumped hydro-storage — it’s so established, in fact, that the U.S. Energy Information Administration divides storage capacity into “hydro” and “non-hydro” pools. The concept is mechanical: Using electricity, water is pumped into an elevated reservoir, where it sits until whoever is managing the water is called upon to generate electricity. Then that entity releases the water, allowing it to flow downhill over turbines that generate power. The Energy Storage Association reportsthat the process can achieve 80 percent efficiency, meaning the downhill trip produces about 20 percent more electricity than it took to pump the water uphill in the first place.

This coming 2017 in Nevada, a similar concept called rail storage is set to make its debut. The idea simply substitutes water for trains — trains that can be filled with heavy objects, then rolled uphill. When the managing entity needs to generate power, it lets the trains roll back downhill, using motors to create electricity.