With wind and solar prices dropping, it can be easy to forget that two-thirds of the globe’s renewable energy comes from hydropower. But hydro’s future is muddled with ghostly costs—and sometimes dubious environmental consequences. Most dams weren’t, in fact, actually built for hydropower. They help stop floods and supply farms and families with water, but […]
Chris Philpot Engineers can further scale up mature technologies such as wind [1] and solar power [2]. Other nascent technologies require considerable innovation, such as hydrogen-powered planes [3] and electric-arc furnaces for steel production [4]. To counteract the worst immediate impacts of climate change, we may need to develop safe and efficient techniques for […]
The world’s most efficient optical rectennas yet can harvest over 100 times more energy from waste heat compared to previous devices, although a new study finds that much work is needed before they can achieve practical value. Rectennas—short for “rectifying antennas”—pick up electromagnetic waves much like car antennas. When a rectenna’s antenna picks up a signal, it […]
SunCulture Kenya has the highest penetration of off-grid solar systems in Africa. Farmers in the region are gaining access to a number of solar-powered devices, including irrigation pumps, egg incubators, grain processors, and refrigerators. It’s a baking-hot February day in Matanya, a village that straddles the equator, a few hours’ drive north of Nairobi. Smiling […]
It’s been a challenge to find sources of renewable energy that are as reliable as the grid would like them to be. And unfortunately, the renewables that are the most flexible and affordable at small scales (like solar and wind) tend to also be the least predictable in terms of output. Hydro and geothermal offer […]
Converting sunlight into hydrogen is a seemingly ideal way to address the world’s energy challenges. The process doesn’t directly involve fossil fuels or create any greenhouse gas emissions. The resulting hydrogen can power fuel-cell systems in vehicles, ships, and trains; it can feed into the electrical grid or be used to make chemicals and steel. For now, […]
Rows of solar panels stretch to the horizon near Chandrasan, a small village in India’s western state of Gujarat. The 1-megawatt solar array snakes through fields flush with crops of cotton and peanuts, but it doesn’t encroach on the precious farmland. Instead, the panels hover above a narrow irrigation canal, which replenishes the surrounding fields. […]
At the ARPA-E Energy Innovation Summit back In 2017, we met a company called Marine BioEnergy that was exploring a concept involving robotic submarines farming the open ocean for kelp to create carbon-neutral biofuel. The concept had a lot going for it: Kelp sucks up carbon as it grows, so any carbon that it later releases […]
In October, when the International Energy Agency pronounced solar energy the “cheapest electricity in history,” their claim rested on largely inefficient panel technologies in the 15-25 percent range. Imagine, say perovskite PV advocates, what new standards solar power could set with efficiencies of 30 percent or more. As of December, photovoltaic panel efficiency ratings north of 30 percent no longer seemed quite so theoretical either. December was the […]
Photo: Patrick Pleul/Picture Alliance/Getty Images Reap the Wind: Turbines of the Jacobsdorf wind farm tower over homes in Brandenburg, in northeastern Germany In 2000, Germany launched a deliberately targeted program to decarbonize its primary energy supply, a plan more ambitious than anything seen anywhere else. The policy, called the Energiewende, is rooted in Germany’s naturalistic […]