An overview of hydropower

Why is hydropower important when other power sources go dark?

Hydropower can ramp up, recoup shortfalls, and stabilize the grid nearly instantaneously. A new study quantifies the energy source’s contribution to grid stability.

Renewable energy basics

Discover the many benefits to using renewable energy resources, but what is it exactly? From solar to wind, it’s the fastest-growing source of energy in the world – and how we can use it to combat climate change.

View breakdowns of the world's and each nation's electricity comes from

These charts show how the shares of generated electricity sources—solar, wind, hydro, nuclear, bioenergy, oil, gas, and coal—have changed since 1985. Since 2010, an increase in renewable sources has offset the share lost by nuclear and fossil fuels.

How electricity is generated by heating water into steam, which rotates magnets

Electrical current—the flow of electrons in a wire—can be produced when exposing a wire to a changing magnetic field. By rotating the magnets, as occurs in a turbine-generator system, the field changes become cyclical. This produces alternating current—flow that moves forward and backward—converting mechanical energy into electrical energy.

Niagara's flow is changed artificially to accommodate tourists and power generation

The natural wonder is also the site of great engineering feats, from the Welland Dam that first allowed ships to travel from the upper lakes to the St. Lawrence Seaway, to one of the first hydroelectric dams.

Explaining how water's movement between different salt concentrations can generate electricity

Water naturally moves from regions of low salinity, such as freshwater, to regions of high salinity, such as ocean water, across a semipermeable membrane. This movement produces pressure that can be harnessed in osmotic power systems to drive turbines and generate electricity, much like in hydroelectric plants.

Solar power is converting the sun's energy into thermal or electrical energy

Solar energy is the most abundant renewable energy resource. It can be captured in photovoltaic cells to generate electricity, solar heating and cooling technologies for temperature control, and concentrated solar power to drive steam turbines.

The engineering underlying the electric grid and why it needs to be modernized

The system includes generators for producing electricity and millions of miles of transmission and distribution lines to transport the energy. The substantial increase in the number of electronic devices and electrical demand since the construction of much of the grid in the mid-1900s has strained infrastructure, requiring continuous upgrades and massive investments in new construction.

Wind energy is categorized into land-based, distributed, and offshore types

Distributed wind turbines efficiently serve on-site energy needs, while land-based turbines are large and generate cost-competitive electricity. Offshore wind turbines capture powerful winds above the ocean and may be pounded into the seafloor using pile drivers or built to float above water at scales larger than the Statue of Liberty.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

Among renewable sources, geothermal rivals hydropower in lifetime cost

As of 2024, the levelized cost of energy—the average cost per unit of energy over the lifetime of a power plant—for geothermal power is surpassed only by solar photovoltaic and onshore wind. Geothermal's LCOE has remained relatively unchanged since 2007, with significant decreases held back by significant upfront installation costs.

As of 2025, wave power projects remain in early research and testing phases

Waves can become a steady source of renewable energy because they do not pause like wind and solar power do. However, funding gaps and the effects of storms, salt exposure, and biofouling—mussels and other sea creatures attaching to wave machines—have presented challenges in scaling the technology beyond testing sites.

Fracking technology can help make geothermal power possible almost everywhere

Generating electricity from Earth's thermal energy has previously required existing underground reservoirs of hot water and permeable rocks through which the fluid naturally escapes. Today, fractures can be artificially created to form fluid pathways, and surface water can be injected underground and brought back to the surface.

Rain-catching tubes provide new hydropower source for tropical regions

An experiment in Singapore showed that charge separation could be established by rainwater flowing through narrow tubes. The separation, which creates a voltage, could be scaled up in regions of high rainfall to provide a clean energy source.

Learn how aquifers and wells provide the largest reserves of accessible freshwater on Earth

Roughly a third of Earth's freshwater is stored underground in aquifers—permeable and porous rock formations where water naturally flows from the Earth's surface and accumulates. About half of this groundwater is accessed through wells, a feat of engineering used for thousands of years.

From evaporation to precipitation: An overview of the water cycle

The water cycle is a natural process that continuously circulates water throughout Earth's systems. View this diagram from NASA to understand how the water cycle incorporates evaporation, condensation, precipitation, and more. First, the sun's heat...

Windmills can be designed to pump groundwater for irrigation or land drainage

A gearbox within the windmill converts the windmill's rotation into the vertical motion of a piston that pushes water up a pipe. It also drives the rotation of an Archimedes screw to move water to higher elevations.

Why water towers are built that way

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Utility companies are often considered 'natural' monopolies

Natural monopolies occur in industries where the upfront costs of entering the market are high, making competition unrealistic. Investor-owned power companies, like Duke Energy, often have natural monopolies, as building alternative power grids and transmission lines is too expensive and impractical for competitors.

Data centers' electrical needs create increased water demands beyond cooling

Each query uses approximately one single-serving water bottle per conversation, but water is also used for steam cycles and cooling in power plants that generate electricity for data centers. Newer cooling methods, such as immersion cooling, where servers are submerged in fluids that don't conduct electricity, can minimize water use.

View major global infrastructure, including power plants, fuel lines, and water pumping stations

The Open Infrastructure Map displays data from the OpenStreetMap database, which aggregates information from freely licensed geodata sources, surveys, and photographic and satellite imagery. It also displays power lines, generators, substations, various chemical pipelines, telecommunications towers, data centers, and more in daytime and nighttime maps.

An overview of crude oil, including its constituent hydrocarbons and refinement outputs

The mixture is primarily composed of molecules of carbon and hydrogen atoms bonded into a variety of shapes and lengths, giving each different chemical properties, such as boiling points. Refining can remove elemental impurities—such as sulfur—after hydrocarbons are separated, ensuring the resulting products can be used effectively in other machines, such as car engines.

Ingenuity and advanced engineering have allowed trains to overcome extreme landscapes

The Jungfrau Railway utilizes electric trains powered by hydroelectric energy to ascend the Swiss Alps, while Poland's Elbląg Canal hauls ships along cable-powered tracks driven by waterwheels. Germany's Wuppertal monorail navigates bends as it glides over a river valley, and New Mexico's Holloman High-Speed Test Track can achieve speeds of Mach 8.6 for rocket sleds.

Why do flash floods occur?

Flash flooding can be more dangerous than traditional floods, occurring within the span of hours and exhibiting rapid currents. Here's how atmospheric conditions and geography combine to make some locations ripe for the disaster.

Explore policy options for reforming the Clean Water Act

The Bipartisan Policy Center brought together experts from across the political spectrum to discuss ways to expedite federal permits for energy and infrastructure projects, including updating some provisions of the Clean Water Act to reduce bureaucratic hurdles without compromising water protections.

Check out hurricane history where you live

The NOAA's historical hurricane tracker lets you explore over 150 years of data to see where hurricanes traveled and made landfall. The tool lets you search by location, name, or year; create maps and tables; and read NOAA storm reports.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Before the current East Wing ballroom project, only two White House renovations in the past 100 years cost more than $10M.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.