Hydropower 101: Transmission, From Dam to Doorstep

Aerial view hydroelectric damOnce the force of a flowing river is turned into electricity at hydropower dams, it still has a long way to go before reaching your house, business, or school. The energy must flow along transmission lines, sometimes hundreds of miles from its source.

When electricity first leaves a dam, it is high voltage, meaning it’s very powerful—too powerful to run our appliances and electronics. High- voltage transmission is the preferred method to move electricity across long distances because less electricity is lost in transit. High-voltage transmission wires, or conductors, are typically strung between tall steel towers—the kind you see along highways and in the countryside.

When the electricity nears cities and communities, it passes through a substation that uses transformers to change the electricity into a lower, more usable voltage. From there it travels on distribution lines, which use thinner, lighter conductors that are typically strung between wooden poles. These lines carry energy through neighborhoods to the electric outlets that power your lights and charge your smartphones.

Getting hydropower to homes and businesses takes careful planning, as transmission lines can only carry the amount of electricity that will be consumed. To keep the right amount of power flowing, computers calculate how much electricity should be sent when and where, across the system.

The people behind the power

It may seem like magic that water can turn into the energy that powers your television and lights at the push of a button or the flip of a switch. None of it would be possible without skilled individuals building and maintaining the system that brings electricity to your home. Transmission lineworkers manage the world behind your light switch.

These highly skilled women and men are electricians who are specially trained to work on transmission and distribution lines. They not only construct lines, but they also maintain them and restore power when there is an outage. Some work on the ground. Some work on the lines and towers. Some even work from helicopters that lift and place transmission towers. The job they do is dangerous and requires carefully managing the powerful electricity that flows through the lines. They risk electric shock and burns and work from great heights, often on nights and weekends, and in less-than-desirable weather conditions.

Thanks to transmission systems—and the lineworkers, substation operators, dispatchers, and countless other people who keep the grid operating—our communities are able to enjoy the benefits of hydropower generated far from our front door.

Source: Bonneville Power Association.