Watt’s Up With Hydropower? How We Can Harness Nature’s Energy Source for a Greener Future

Hydropower has helped meet our energy needs for thousands of years. What started as utilizing waterwheels on rivers has turned into building colossal dams. But that's only the beginning of how the energy source can

shape a greener future. One person who knows that all too well is

Dr. Melissa Lott.

Lott is internationally recognized for her research and contributions to the global energy sector and has worked as an engineer and advisor for nearly 20 years in the United States, Europe, and Asia. Now, as the director of research at Columbia University’s Center on Global Energy Policy, she aims to increase our understanding of energy systems and their impact on the environment and public health, all with an aim of transitioning to more

sustainable energy systems—like hydropower.

So what exactly is hydropower, how does it work, and how does it benefit the planet? Lott dives into all of these questions and more in a recent episode of

Good Together. Here's everything you need to know.

Hydropower, also known as hydroelectric power, is one of the oldest forms of

renewable energy in the world.

More than

2,000 years ago, the Greeks harnessed the power of hydropower by employing waterwheels on rivers to grind wheat into flour. Today, we're still utilizing the natural flow of moving water in order to generate electricity—just with upgraded systems.

"Think about the history of hydropower. Or using water to do work, I guess, is really a better way to say it—at least in terms of its early days," Lott says. "When you think about milling different projects, or cutting our lumber, just spinning wheels with flowing rivers is something that we've done for a long time as a human society. It's only been more recently that we've actually started using water to turn a turbine to convert that energy into electricity, which does work for us in a different way."

As a whole, Lott says that aside from hydropower being one of the oldest sources of renewable energy in the world, it's also one of the largest. "It currently accounts for something like a third of U.S. renewable electricity generation, and 6% overall of total U.S. electricity," she says. It's also a much more sustainable source than other options currently available to us.

"Hydropower is something that we call 'firm, dispatchable, clean electricity.' So the clean is relatively self-evident in the sense of you're not producing air pollution, you're not really producing greenhouse gas emissions. Though, of course, when you dam a river, you are burying lots of trees and lots of different types of organic products. And they do decompose over time," Lott says. "So there are some impacts, but they're a lot less than, let's say, the equivalent of electricity if you're using natural gas, coal, or something like that."

By "firm and dispatchable," Lott says she means hydropower is around 24/7, 365—aka all the time. That's not always the case with other renewable energy sources, like

solar energy and wind energy.

"As long as you have water above your dam, it provides electricity whenever you need it," she says. "If the wind dies down, or the sun sets, or another thing in your electricity system isn't producing electricity, hydropower can be there, and it can act as a really big water battery."

When thinking about hydropower, there are two prime ways we can use it. First, it's what the world traditionally thinks about—aka a dam, where a big concrete structure is built in the middle of a flowing waterway.

"We put some turbines in it, and we let the water flow out in a controlled manner. And when it flows through, it actually spins the turbine and generates electricity," Lott says. "In the meantime, it often creates a lake at the top of it, and we might use that lake for recreation—we water ski on it, we go swimming, fishing, all of those things."

In this system, the flow of water is controlled. In the second, that's not the case and is what Lott refers to as a "run-of-river" hydroelectric system.

"Instead of blocking the water and controlling it in a very large way, we put turbines that can spin just in the flow of the river—we don't stop the river, we just put things in the middle of it and say, you know, I'm not going to control the flow of water. I'm just going to allow it to do some work for me," she says. "It generates electricity in that way, and that's really common in parts of the world as well."

Climate change has the ability to affect many things—hydropower included.

"In the face of a changing climate, where, when, and how our rainfall patterns occur is changing. That has a direct impact on hydropower," Lott says. "So when we look at the planning of our electricity systems, we might think often about, well, a fossil fuel power plant needs water to cool itself—same with a

nuclear power plant. So water is really important in those cases. Well, in the case of hydropower, it's the fuel. If you don't have it, you end up in a tough spot."

According to Lott, some countries have already struggled with climate change's impact on hydropower, with New Zealand being one of the most notable.

"They get 70% rough numbers of their electricity from hydropower in different forms. And they have these dry-year cycles that can last many years," she says. "What happens when you don't have a lot of rain for several years in a row, when you don't have the snowpack and all of that? Well, you don't have the fuel you need to actually produce the electricity you need. And you have to be able to come in with other resources."

Lott says this is proof that planning for our future needs is super important. "What that means is requiring our energy planning models (the ways we plan where a new power plant is going to go), and also our climate models (which talk about what the weather is going to look like in a few years and what rainfall patterns are going to look like), that they actually talk to each other and interact," she says. "This is just one of the ways that we can really improve how we're planning things out."

Some conversations are already starting. "Here in the United States is one example," Lott continues. "The New York Power Authority in the northeast announced the project they're doing in partnership with Argonne National Laboratory, who has some great electricity planning models, and then also climate models. They said, 'Hey, can you integrate the two? And let's look at what kind of risks we're facing in the future so that we can plan on taking that into account.'"

Lott thinks over time, this will become par for the course—something everyone considers. Instead of basing your planning off the past 50 years, it will be looking at what the next 50 years will look like.

As previously mentioned, hydropower typically looks like big dams or run-of-river systems. But Lott says the future is looking bright, and more technologies are on the horizon.

"There's really exciting innovations and investments going on. How do we use our oceans? How do we think about tidal power? How do we think about wave power? How do we think about the energy that we can harness from the movements within our oceans, and then even on land, so away from our oceans? How do we think about the next generation of something we call 'pumped storage'?" she says. "I've seen some really nifty concepts about saying, 'Hey, if all it needs is an elevation change, what about using an abandoned mine that's underground that fills up with water, and I pump that water to the surface and then I let it flow down a different time of day?' There's just different ways to think about how we use water, which is all around us in different forms."