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Earth Day: How Ultracapacitors Conserve Energy

Earth Day: How Ultracapacitors Conserve Energy

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Fifty years ago Earth Day was launched, and its golden jubilee will take place this Saturday. Earth Day’s mission is to educate the public about environmental issues and ways that individuals, government and businesses can conserve our planet’s resources.

Energy storage is one key strategy for energy efficiency in a diverse range of industries. Maxwell Technologies has deployed over 44 million ultracapacitor cells acting as energy storage devices for wind turbines, solar farms, automobiles, trains, and the energy grid.

Ultracapacitors, also known as supercapacitors, are electrostatic energy storage devices that specialize in delivering fast, high power in short timeframes. They complement batteries in applications where batteries are overworked to provide burst power.

In the spirit of Earth Day, here’s a glimpse into how ultracapacitors contribute to energy efficiency across industries today.


Most rail systems use braking pads to reduce the train’s speed, producing excessive friction, heat and noise. Ultracapacitors make trains more energy efficient via regenerative braking—a unique ultracapacitor capability to capture, save, and reuse energy that would otherwise dissipate as heat.

Maxwell Technologies’ ultracapacitors are employed for subway energy recovery in Beijing’s No. 8 rail line. We were awarded the Climate Change Business Journal Award for our ultracapacitor technology in energy recuperation for electric rail systems, including the Southeastern Pennsylvania Transportation Authority light rail.

Wind Turbines

Ultracapacitors ensure reliable access to wind-generated power on the grid by stabilizing short-term power output fluctuation in wind farms and cabling in large-scale deployments. Read about our installation for China Guodian Corporation, the first megawatt-scale, ultracapacitor-based wind farm energy storage system in the world.

Solar Power

Solar power is clean renewable energy, but one challenge with capturing this energy is what to do when clouds block the sun’s rays. The University of California, San Diego runs one of the most advanced microgrids in the United States and employs Maxwell’s ultracapacitors for "solar smoothing” to combat this problem. Ultracapacitors help produce more consistent, higher quality power output during those dips in solar power.

Automotive Vehicles

Today’s cars are being designed with more advanced safety and performance features, and those features demand more power. Ultracapacitors can support complex applications such as active suspension, electric turbochargers, and start-stop systems.

To learn more about how ultracapacitors contribute to energy efficiency, visit our page Where Ultracapacitors Work. Thanks for reading, and happy Earth Day.


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