The February 2023 issue of IEEE Spectrum is here!

Close bar

These Exercise Machines Turn Your Sweat Into Electricity

Exercise equipment that generates power is the latest fad. But will the economics work out?

7 min read
Photos: Stan Honda/AFP/Getty Images
Photos: Stan Honda/AFP/Getty Images

greenmachine01

photo showing wattage displayDon't Stop: Retrofitted by a company called the Green Revolution, exercise bikes at a New York Sports Clubs gym generate electricity; a display shows the biker's wattage.Photos: Stan Honda/AFP/Getty Images

Keep reading...Show less

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions

Caltech Team Launches Experimental Space-Based Solar Array

The satellite will test some of the tech needed to wirelessly beam power from orbit

4 min read
A lightweight gold-colored square frame for a solar power array, seen flying in space with Earth in background.

Artist's conception of Caltech's Space Solar Power Demonstrator in Earth orbit.

Caltech

For about as long as engineers have talked about beaming solar power to Earth from space, they’ve had to caution that it was an idea unlikely to become real anytime soon. Elaborate designs for orbiting solar farms have circulated for decades—but since photovoltaic cells were inefficient, any arrays would need to be the size of cities. The plans got no closer to space than the upper shelves of libraries.

That’s beginning to change. Right now, in a sun-synchronous orbit about 525 kilometers overhead, there is a small experimental satellite called the Space Solar Power Demonstrator One (SSPD-1 for short). It was designed and built by a team at the California Institute of Technology, funded by donations from the California real estate developer Donald Bren, and launched on 3 January—among 113 other small payloads—on a SpaceX Falcon 9 rocket.

“To the best of our knowledge, this would be the first demonstration of actual power transfer in space, of wireless power transfer,” says Ali Hajimiri, a professor of electrical engineering at Caltech and a codirector of the program behind SSPD-1, the Space Solar Power Project.

Keep Reading ↓Show less

Forecasting the Ice Loss of Greenland’s Glaciers With Viscoelastic Modeling

Researchers at the Alfred Wegener Institute in Germany are developing new models to simulate how glaciers behave

8 min read
Aerial view of Nioghalvfjerdsbræ showing the extensive patterns of the crevasses

This sponsored article is brought to you by COMSOL.

To someone standing near a glacier, it may seem as stable and permanent as anything on Earth can be. However, Earth’s great ice sheets are always moving and evolving. In recent decades, this ceaseless motion has accelerated. In fact, ice in polar regions is proving to be not just mobile, but alarmingly mortal.

Keep Reading ↓Show less
{"imageShortcodeIds":["32356952","32356923","32356954"]}