A look at how power is restored after an outage on the electric grid

Examining the causes of power outages, from system damage to preventative measures

Stray balloons, contact with trees, malfunctioning equipment, and severe weather are among the causes of failures that can cause widespread, unplanned blackouts. Although contingency options that rely on alternative transmission pathways to deliver electricity from generators to consumers may be possible, some shutoffs, brownouts—available power is reduced—and cycles of repeated outages may be intentionally implemented to protect public safety.

Learn how critical services, infrastructure, and people would be impacted by a US-scale blackout—a nationwide, long-term failure of the electric grid.

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.

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.

How microgrids can modernize electric grids to meet 21st-century demands

Just as having a single, outdated internet service provider leaves an area helpless in the case of an outage, failures in the electric grid can be devastating to communities. For this reason, hospitals, data centers, and other structures have their own backup power supplies. However, decentralized microgrids would provide areas with their own electricity generation and storage, thereby reducing overall grid load and reliance while enabling better electricity management.

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.

Understanding the power grid and how renewable sources fit in

The power grid is evolving to include ever-higher levels of solar and wind, which don't provide inertia. Should system planners and operators panic?

The history of the North American power grid, which is composed of five major grids

Thomas Edison's Pearl Street Station was the first US commercial power plant, burning coal to power lamps for some Manhattan residents. Over time, local power plants would be bought out by larger ones, forming interconnected systems spanning multiple states. Today, the Eastern Interconnection and Western Interconnection are the largest of these systems.

Simulate the effects of changing supply and demand on the electric grid

In this application, users can modify the demand of fictional cities and the supply of various generators, including a nuclear power plant and a wind farm, which can be disconnected from the grid. Notice that current may flow into or out of external systems to compensate for available generation. See what it takes to cause a blackout in different cities or shut down the entire grid.

View a map of the balancing authorities managing electric systems and costs throughout the continental US

These are made up of utilities, Power Marketing Administrations—hydropower marketers from the Department of Energy—and groups of utilities that have formed regional entities called Regional Transmission Organizations or Independent System Operators. Collectively, balancing authorities ensure supply meets demand and can direct utilities to implement rolling blackouts to prevent permanent damage to electrical equipment.

Learn why electrical substations are needed to provide safe electricity with minimal energy loss

These typically fenced-off facilities with steel boxes or cylinders topped with cone-like caps house circuit breakers, fuses, and switches that can isolate sections of the grid to prevent electrical failures from spreading. Substations use transformers to modify electrical voltage and are customized to the generation, transmission, and distribution networks they interconnect.

During emergencies, backup diesel generators in data centers emit substantial pollution

During power outages or when the power grid is at insufficient capacity, these generators emit 200 to 600 times more nitrogen oxides—a greenhouse gas—than natural gas plants, as well as fine particulate matter linked to respiratory disease.

More batteries in the power grid would create an on-demand energy reservoir

Most power grids are inefficient because they require enough generation capacity at all times to avoid blackouts. This means at any given time, as much as 50% of generating capacity at power plants can go unused. Batteries would reduce this inefficiency and allow for real-time adjustments.

The benefits and risks of smart grids, from improved efficiency to cybersecurity risks

By using a network of devices, including digital meters, sensors, and controllers, smart grids can quickly detect mechanical issues and fluctuations in supply and demand, automatically adjusting electricity flow to prevent cascading failures. While this is important for variable solar and wind power generation, many of these computer systems are designed to be controlled remotely, which increases the risk of malicious access.

Understanding how non-profit entities manage electric grids to ensure supply-demand balance

Independent System Operators in smaller areas and Regional Transmission Organizations that operate across multiple states run wholesale electricity markets. Electricity suppliers can submit competitive bids to meet estimated demand in day-ahead markets while keeping consumer costs low. ISOs and RCOs also inform markets of deviations in these estimates so that suppliers can adjust how much power they generate, which is then bought and sold in real time.

Discover why Texas runs its own electric grid, separate from the other US interconnections

In 1935, electrical utilities in the Lone Star State opted to rely on the state's own fossil fuel reserves to power an independent electric grid. While this prevented the federal oversight required for the Eastern and Western Interconnections that span multiple states, it also meant Texas's grid was unable to draw sufficient backup power during the winter 2021 power grid failure.

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.

Electrical grids worldwide must double their power delivery capacity by 2050 to meet surging demand from AI and electric vehicles.

Why decarbonizing the entire electric grid is impossible with its current infrastructure

Fossil fuel plants can be built anywhere and have thus typically been built near highly populated areas, such as coastal cities, where electricity demand is high. However, certain renewable resources operate most efficiently in specific regions, such as wind turbines in the Midwest, and therefore require substantial transmission infrastructure to be constructed to transport the generated electricity.

Watch a timeline of the history of electricity, from observations of static electricity in antiquity to the War of the Currents—a rivalry to establish the ideal system for electric grids.

View a dashboard of hourly electricity demand and generation across the continental US.

Electric grids that rely on solar power must compensate for reduced electricity generation during solar eclipses.

Tesla's alternating current power's most of the world's electric grids

In 1879, Thomas Edison’s light bulb relied on direct current, but such currents can't efficiently transmit power over long distances. Nikola Tesla introduced alternating current, which feature far fewer energy loses. Despite Edison’s attempts to discredit AC, Tesla proved its efficiency by lighting the 1893 Chicago World’s Fair.

View a breakdown of global electricity generation in 2025, led by coal power plants.

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.

Visualize how alternating currents—electricity that periodically changes direction—are generated by rotating magnetic fields, as occurs in turbine-generator systems.

Niagara power helped electrify early New York City

Tesla's AC system at Niagara Falls was so successful that electricity generated there lit up Broadway theaters and powered NYC's subway system in the early 1900s.

Niagara Falls helped decide the battle between AC and DC power

In the 1890s, Niagara Falls became the proving ground for alternating current (AC) when Tesla and Westinghouse built the first large-scale AC hydroelectric plant—defeating Edison’s push for direct current (DC) in the US electrical system.

Being struck by lightning has a mortality rate of about 10%

Near-immediate deaths are the result of electrical disruptions in the heart and nervous system, causing cardiac arrest, but severe skin burns, temporary paralysis, and blown eardrums are more common. About 74% of survivors are left with a long-term disability, which includes brain damage and changes in memory and mood.

The unpredictability and brevity of lightning make lightning power impractical

While a typical lightning strike provides 30,000 amps at 300 million volts, the bolt only lasts about 30 microseconds. If the electrical surge could be captured—assuming one knew beforehand where it would strike—it would only provide enough electricity to power one home for about 6.4 hours.

Larger shares of solar power generation produce larger energy demand curves

Because solar energy is only available during daylight hours, transitioning an electric grid to solar requires significant ramp-ups and ramp-downs of other energy sources during mornings and evenings to compensate. Widespread adoption of affordable energy storage solutions can soften these curves.

Minor technology failures can spiral into massive internet outages

A mix of centralized cloud infrastructure and legacy protocols leaves the internet susceptible to downtime from minor cyberattacks or software bugs, infrastructure damage caused by extreme weather, and human error if a DNS service provider—the internet's phone book—or a backend system, such as Amazon Web Services, were compromised.

Niagara Falls is New York State’s biggest electricity producer

The Robert Moses Niagara Power Plant and Lewiston Pump-Generating Plant together produce up to 2.6 million kilowatts—providing about 20% of New York State’s hydropower and supplying electricity to over 3 million homes.

An overview of hydropower

Hydropower, or the use of the natural flow of moving water to generate electricity, is one of the oldest and largest sources of renewable energy.

See how a 2018 fire in Paradise, California, exposed the limits of emergency coordination

This Frontline documentary shows how the Camp Fire stretched and ultimately overwhelmed the complex web of agencies involved in emergency response, including fire suppression, 911 dispatch, law enforcement, and emergency management, with catastrophic results.

View an interactive map of US power plants, which generate electricity from coal, gas, water, biomass, nuclear fuel, oil, sunlight, and wind.

Establishing the wind power grid required incentives, reliability, and affordability

Although wind was harnessed to generate electricity for individual buildings in the late 1800s, high costs, mechanical issues with turbines, and better fossil-fuel alternatives delayed wind power's widespread growth. After the oil crises of the 1970s, governments sought alternative energy sources and, in the decades that followed, provided tax credits to expand the wind power market.

All clean energy technologies rely heavily on critical minerals

Although many of these minerals have been used for decades, such as copper in electrical wiring, the accelerating demand for them has strained existing extraction and processing systems. Supply chain disruptions for these materials may delay and increase the cost of transitioning to solar, wind, hydroelectric, and geothermal power.

Despite electric usage concerns, EV charging accounts for less than 1% of grid load

Other popular myths about EVs include battery failure concerns—failure rates are less than 1% on newer models—and that there are no places to charge cars, though both at-home outlets and more than 77,000 stations on the road are available.

Explore how global teams coordinated by the UN's International Search and Rescue Advisory Group find and rescue survivors of large-scale earthquakes, from preliminary surveys to recovering bodies.

View a gallery of whimsical transmission tower designs from around the world

Despite their importance to the functioning of the electric grid, these structures are often considered aesthetically unpleasant. To remedy this, some have been transformed into art installations featuring stained glass and colorful lighting, or built with whimsical designs, such as clown faces or giant bodies.

View the layout and components that make up a typical data center

Alongside server rooms for the storage, processing, and transmission of data, data centers include climate control systems to manage the heat generated by microchips, backup systems to ensure systems can run during power outages, offices for on-site personnel, and monitoring and security stations to provide continuous protection against physical threats.

Find out how much energy in the US comes from renewable sources and other FAQs

Browse frequently asked questions about renewables, from the amount of energy production by state to the cost of electricity generation by power source.

Electricity can be lethal because it can disrupt the nervous system, which controls critical bodily functions that rely on electrical signals between cells, such as breathing and heart rate.

Utility companies are often considered 'natural' monopolies, which occur in industries where the upfront costs of entering the market are high, making competition unrealistic.

See technicians use rappelling gear to make wind turbine repairs from 35+ stories up

Although drones are used to conduct initial reviews from the ground, mechanical engineers trained in turbine maintenance face extreme risks during close inspections more than 150 meters off the ground.

In the photovoltaic effect, light generates electricity by creating a charge imbalance after knocking electrons out of atoms in the semiconducting materials of solar cells.

Some scientists hypothesize that stressed rocks can discharge built-up static electricity in the form of lightning—a phenomenon known as fracto-luminescence, or earthquake lights.

Data from 2020 suggests that fossil fuels are the most dangerous and least clean energy sources, causing the most deaths and emitting the most greenhouse gases per unit of energy generated.

Restoring desert ecosystems: Successes, failures, and ongoing efforts

This article discusses ecological restoration in desert environments, focusing on the various techniques and challenges related to restoring desert ecosystems. In the complex endeavor of desert restoration, experts attempt to pinpoint the most...