Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.
Hydroelectric power is the most widely-used renewable energy source in the world. It creates about one-sixth of the world’s electricity. But how exactly does it work, and how does it fit into our energy future?
We had Luci Jones and Fatima Husain from our Possibly Team look into this question. Welcome, Luci and Fatima!
Luci Jones: Hi, Megan!
Fatima Husain: Hello!
Megan Hall: So what exactly is hydroelectric power?
Luci Jones: That’s a great question! To get a clear definition, we spoke with Alejandro Moreno, the Director of the Water Power Technologies Office at the U.S. Department of Energy.
Alejandro Moreno:
You have a dam or what we call an impoundment, that’s blocking water and holding water in reserves. And then when you release that water, it flows through a turbine and spins that turbine. And it’s the spinning of that turbine that generates electricity.
Megan Hall: So, how do these dams compare to other sources of renewable energy, like wind and solar power?
Fatima Husain: Well, globally, hydro produces about 3 times more electricity than wind and 6 times more electricity than solar.
Luci Jones: But wind and solar will almost certainly pass hydro before the end of this decade.
Fatima Husain: Still, hydro has one big advantage — consistent power production. Remember, If the wind isn’t blowing or the sun isn’t shining, wind turbines and solar panels don’t generate electricity.
Luci Jones: Alejandro says that hydropower is almost always available because as long as there is water uphill, it will flow downhill if you let it.
Alejandro Moreno:
Hydro is in some ways, a big battery, or a big reserve sink of generation
that can be turned on when you need it, and can also respond very quickly to fluctuations in other generators’ ability to provide power.
Luci Jones: Hydropower can also store electricity using something called “pumped storage.”
Megan Hall: How does that work?
Fatima Husain: Let’s say a dam, or a wind farm, is producing more electricity than is needed at a particular moment. That electricity can be used to pump water from the bottom of the dam to the top.
Luci Jones: Then, later, when that power is needed, operators can release that water back through the dam to create more electricity.
Megan Hall: This all sounds great — but, what are the consequences of hydropower?
Luci Jones: Like with all energy sources, there are downsides. New dams can flood big stretches of land, which can displace people from their homes.
Fatima Husain: A report by the World Commission in 2000 found that between 40 and 80 million people worldwide have been displaced by dams.
Luci Jones: Some even think the number might be higher if you take into account effects like less access to land for farming and fishing.
Fatima Husain: Dams also dramatically change the shape of rivers and affect the habitat of thousands of species that depend on them, including endangered life like river dolphins.
Megan Hall: Are scientists trying to do anything about these problems?
Luci Jones: Alejandro is working on a few projects. One of them is called the “whoosh device.” It’s basically a vacuum chamber that sucks up fish and shoots them over dams.
Megan Hall: So, do the benefits of hydropower outweigh the harms? Is it worth investing in more of it?
Fatima Husain: Well, we’ve pretty much dammed all the waterways that we can in the United States, so nationally…
Luci Jones: It’s more of a question of how we can maximize the hydropower we already have, in a way that is environmentally sustainable.
Fatima Husain: That might include retrofitting dams so more of them can use pumped storage.
Luci Jones: Globally, many countries are still planning or constructing hydropower dams. And no matter what, hydropower will continue to be part of the global energy picture because it’s efficient and reliable.
Fatima Husain: But I wouldn’t look to hydropower as our only source of renewable energy in the future, particularly where there is a lot of demand for electricity.
Megan Hall: Got it! Thanks, Luci and Fatima!
That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts.
Possibly is a co-production of the Institute at Brown for Environment and Society and the Public’s Radio.
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