Aerial view of a hydroelectric power plant at the Hoover Dam, one of the most famous dams in the world.

Alright folks, if you’re a repeat reader on the Corefficient blog, you know that we have quite an interest in the evolving energy market, particularly where renewable energies are concerned. More particular still, we devote a lot of time illustrating “how” electrical transformers support these burgeoning technologies and convert the energy into power for your homes and businesses.

We’ve talked about solar energy.

We’ve talked about wind energy.

So, we think it’s only right that we talk about the oldest and most widely used form of renewable energy – hydroelectric power. Hydroelectric power is the largest of all the renewable energy sources and accounts for 6.7% of worldwide electricity production.

Hydroelectric energy derives its power from the movement of water. Flowing water creates energy, which is captured, and converted into electricity. The rain or snow that falls from the sky either evaporates or absorbs into the soil. The remaining water, known as runoff, travels until it reaches rivers, ponds, lakes, and oceans. It is during this flowing movement that a hydroelectric power plant captures the energy by the water through a turbine, which spins and activates a generator to produce electricity.

This act turns the kinetic energy of the flowing water into mechanical energy, which is then converted into electricity.

Historically, one of the first uses of this method was for grinding grains, but in the modern era, hydroelectric power plants take many forms.

First off, we have run-of-river facilities. Like those in historical times, run-of-river facilities rely on natural water flow, like rain and snow. Because of this reliance, this kind of facility is hard to consistently create energy.

Although some hydroelectric power plants can be found on rivers and canals, the most common and reliable form of power plants are found by dams. Impoundment facilities are the most common – which uses a dam to create a large reservoir of water.

A large power line tower, with its reflection being beautifully mirrored in a nearby body of water

“Okay, thanks for the catch up, Corefficient. But where do electrical transformers come in?”

Glad you asked.

So, the hydroelectric power plant generates the energy, but the electricity that is generated isn’t the correct voltage to power people’s homes. This is where electrical transformers come in. The electrical transformer converts the alternating current that the hydroelectric power is generating into a high voltage current.

This converted power supply that is coming from the transformer is connected to the national grid, where it is then distributed for domestic and industrial use. This high voltage current is still a bit too strong for most applications, and so a series of transformers are installed at various locations that reduce the voltage to a voltage required for domestic and industrial applications (110V or 230V).

Once the electricity is properly converted, it must be delivered to where it is needed. Dams are often found in remote locations, which requires that the generated power be transmitted over large distances to get to our homes, schools, offices, and any other facilities. At local substations, transformers reduce the voltage so electricity can be divided up and directed throughout an area. Transformers on poles (or buried underground, in some neighborhoods) further reduce the electric power to the right voltage for appliances and use in the home.

Wow, power really travels a long way! In order to move away from fossil fuels, we must overcome these technical challenges in order to have a safer and greener tomorrow.


Based out of Monterrey, Mexico, Corefficient’s state-of-the-art facility is committed to adding value to their transformer core products. Part of the National Material L.P. family of companies, Corefficient specializes in the fields of core engineering, transformer core design, magnetic core expertise, cold rolled steel, grain oriented steel, electrical steel, and – most importantly – customer service.

Visit Corefficient online @, contact our North America Sales Engineer: 1(704) 236-2510 or call us directly in Monterrey, México: (81) 2088-4000.