Introduction to Hydropower – Video
Summary
Introduction to Hydropower
This video introduces students to hydropower, one of the most widely used sources of renewable electricity in the world. Hydropower generates electricity by using the natural movement of water driven by gravity.
Students learn how the water cycle moves water uphill through weather systems, while gravity pulls it back downhill. Hydropower dams capture this movement by directing flowing water through turbines that spin generators to produce electricity. Some of the largest power plants in the world are hydropower dams.
The video explains why hydropower is considered a highly flexible electricity source. Hydropower plants can quickly increase or decrease electricity production to match changing demand on the electric grid. Because of this flexibility, hydropower can provide both steady base load electricity and rapid response during times of high electricity demand.
Students also explore the advantages and limitations of hydropower systems. While hydropower produces electricity without direct air emissions and can operate for many decades, building large dams requires major construction and can have environmental and social impacts. Reservoirs may alter ecosystems, affect river systems, and require relocation of communities.
Another challenge is that the number of suitable locations for large dams is limited. Many of the best hydropower sites in developed countries have already been built. Future growth in hydropower is expected to occur primarily in developing regions and through smaller projects or upgrades to existing facilities.
By examining both the benefits and tradeoffs of hydropower, students gain a better understanding of how renewable electricity systems work and how societies evaluate energy resources.
This resource supports lessons on renewable energy, electricity generation, water resources, and energy systems, helping students understand how natural forces can be used to produce electricity.
This video is meant to be used with the Introduction to Hydropower Lesson. For a more in-depth look, check out the Science of Hydropower Lesson and video. Pair this video with lessons on The Electric Grid, Environmental Impacts of Energy, or Energy Choices to explore how hydropower fits within broader energy systems.
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Transcript:
[Dr. Scott W. Tinker] Hydro is the ideal electricity resource, and that’s why we’ve developed pretty much all of it. To begin with, the energy comes from something we’ll never run out of: gravity. Weather moves water uphill, and gravity brings it down through the turbines. And voila, electricity. Lots of it. The biggest power plants in the world are dams, and they can spin up the turbines almost instantly whenever we need the power. This means hydro can be always-on base load power, or it can follow electricity demand by the minute, all with zero emissions. And although the plants are expensive and high-impact to build, they’re cheap to operate, and may last for 100 years. But the water may not. As population and development increase, so do water demands for other things, like agriculture. And climate change could bring more droughts and hotter summers. Maybe more important, the places to build hydropower are limited. In the developed world, we’ve nearly used them all. The big projects in the future will be in China, India, and the developing world. But there, as everywhere, damming a river has environmental, social, and economic impacts that not everyone is ready to bear. For these reasons, as global energy demands rise, hydro will supply a shrinking percentage of it, and the growth of this clean, flexible resource will mostly be in small local projects and refitting old ones with better equipment. So that’s hydro. It’s phenomenal, but we won’t see much more of it.