From Rivers to Ocean Waves

Is Water the Answer to Renewable Power?
Written by Karen Hawthorne

It’s pretty hard to miss how countries around the globe are making the environment a priority. From the latest Biden administration initiatives to put green power and renewable resources on the agenda to pledges by leading nations to meet new carbon-neutral goals by 2050, there’s one source that’s been achieving these targets for more than 100 years—hydroelectricity.

According to the U.S. Energy Information Administration, hydroelectricity accounted for about 6.3 percent of electricity generation and about 31.5 percent of total renewable electricity generation in 2021.

For a quick refresher on how hydroelectricity works, you need to begin with the water cycle. Water, for the most part, has spent all its time on the planet in the following way: it evaporates from the ground, then comes back down as rain or snow, and then makes its way to rivers, lakes, or oceans.

To make hydroelectric power, moving water is needed. The hydroelectric plants use pipes to force the water through turbines to generate electricity. Most of this is done by way of large dams, situated on major rivers bringing the water, where it evaporates and enters the cycle all over again.

Global hydroelectric power capacity comes in at 1,270 gigawatts (give or take). One gigawatt is equal to a billion watts, and just one gigawatt is enough to power 100 million LED lights, or about 2,000 Corvette Z06s (if you are a gearhead).

The top five hydroelectric-producing countries are China, the U.S., Brazil, Canada, and Russia. And it’s China that produces the most by a longshot; of the 1270 gigawatts produced worldwide, China generates more than a third at 341 gigawatts.

Hydroelectricity itself has become one of the most used sources of renewable energy around the world. The key to its success in many ways is that it is one of the most reliable and renewable sources of power.

There’s the advantage that hydroelectric plants convert 90 percent of energy into electricity. This compares to fossil fuel plants that top out at 60 percent efficiency.

Also, hydroelectric facilities last for a very long time. For example, the Chaudière Falls plant along the Ottawa River in Canada has been operating since 1891. Ultimately, with maintenance and updates, hydroelectric power can be extended practically indefinitely. That’s one of the reasons for Canada being one of the few countries in the world that’s a net exporter of hydroelectricity.

And while all this may sound utopic, there are, however, serious issues that are making some think twice about hydroelectric energy as a clean solution to power generation.

A growing threat to hydroelectricity generation is lack of rainfall and drought. In the U.K. and Europe, old villages are re-emerging that were once drowned by new dams and reservoirs. These falling water levels have reduced electricity generated to the tune of 20 percent, complicating Europe’s overall energy woes.

In a BBC article, Eddie Rich from the International Hydro Association commented on the seriousness of the situation: “We are going to face a problem this winter. And that should be a wake-up call to have more investment in infrastructure for the next few years.”

All of this, combined with the crisis in Ukraine, may add up to energy-use restrictions for people in Europe over winter.

The challenge for producing more hydroelectricity in developing countries is finding a suitable site to build a power plant. Since nations have been building power plants for about 140 years, it’s become harder to locate sites that are both stable and will not heavily impact the environment. This is leading would-be dam builders to search out more treacherous locations deeper into the Amazon and the Himalayas, locations that are often more treacherous.

In a Bloomberg article, Homero Paltán, a water and climate researcher at Oxford and the World Bank points out how environmental changes are making it harder to plan hydroelectric plants. “Hydroelectric projects are often planned according to a climate that is probably not relevant anymore,” says Paltán. “This is not well discussed, and it has repercussions for global energy markets.”

The scary data is that as much as 80 percent of planned hydroelectric sites are in areas where droughts are expected to become 10 percent longer. This will present challenges, especially in developing countries where clean and renewable sources of power are most needed.

And the big knock against hydroelectric power is what troubles most clean power generation—the sheer massiveness, in this case, of the dams.

The scale of some dams is mind-blowing. An example is the Three Gorges Dam on the Yangtze River in China. This dam produces 22,500 megawatts of power (the most productive hydroelectric dam in the world) but it also displaced 3.67 million people. Likewise, projects in South America, Southeast Asia, and Ethiopia are exerting massive pressure on biodiversity and wildlife habitats.

You don’t have to go far to see the impact of damming rivers. The Grand Coulee Dam built on the Columbia River in Washington State is the biggest power producer in the country at 6,809 megawatts. But the cost includes disrupting salmon migrations and the displacement of native peoples during its construction in 1941. As a result, billions of dollars have been spent trying to solve the problems the dam caused, including $1 billion on saving salmon.

All of this leaves the question: is this form of hydroelectric power ultimately worth the true cost generated by these dams?

The good news is there are alternatives. One example is microgrids, which are small, decentralized power hubs that use local sources to produce energy. And while they have been around for some time, AI technology is helping them turn into low carbon emitting projects that also reduce the overall costs of power for communities.

Rotterdam in The Netherlands is Europe’s biggest port, handling 30,000 vessels a year. It’s also now the world’s first high-frequency, decentralized energy market. Port users are equipped with an AI application that uses blockchain technology to validate transactions, and energy prices fluctuate based on supply and demand.

Since the opening of the market, port users have enjoyed an 11 percent reduction in their costs, while producers have seen a 14 percent increase in revenues, all the while reducing wasteful excess energy.

James Rilett, Global Innovation Director at S&P Global Platts, one of the firms behind the AI application, says, “When we first met to discuss the project, the Dutch government was being sued by citizens for failing to meet its carbon emissions targets. The port is a state asset that accounts for a third of the country’s emissions, so people were very interested in the initiative.”

The goal is to ultimately save up to 30 million tons and achieve carbon neutrality by 2050.

There’s the somewhat staggering fact that tens of thousands of dams in the U.S. don’t produce power, so converting some into power plants could greatly benefit the country’s power grid.

Another alternative in use now is pumped-storage hydropower. This essentially means charging a big battery when plentiful power is available that then pumps water to a higher elevation (which is key to power production). The water can then be released to turn power turbines at any chosen time to feed into and stabilize the power grid.

Other concepts that are a little far out include wave and tidal energy. For tidal energy, a difference of 16 feet is required between low and high tides. Both the Pacific Northwest and the Atlantic Northeast are good candidates for this but work on developing tidal turbines is ongoing.

Like the tides, the waves of the oceans are also jampacked with potential energy. The waves have the potential to power everything from coastal cities to de-salinization plants (that remove salt from ocean water so that it’s drinkable) and even naval bases. But these are still in the future as research to make them cost-effective continues.

While it would be nice to say that hydroelectricity is a no-brainer in a greener power grid, there’s much to ponder when comparing what it offers to what it takes to set up. Ultimately, it may be a combination of the existing traditional sources of hydroelectric plants that are already in use—and could well remain in use for the foreseeable future—while looking to harness new sources of water to create green power.

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