No matter how we make electricity, it takes up space. Coal requires mines, and plants to convert it into electricity. Nuclear power takes uranium mines, facilities to refine it, a reactor, and a place to store the spent fuel safely. Renewable energy needs wind turbines or solar panels. So how much space would it take to power the whole world? Ex...

Why aren't more people investing in Africa's green energy? Environmental researcher Rebekah Shirley outlines the continent's immense potential for renewable power and calls for collaborative international investment -- and partnership -- in Africa's climate future. "Let's cut past the talk and focus on unleashing the avalanche of a clean energy ...

The US consumes 25% of the world's oil -- but as energy tycoon T. Boone Pickens points out onstage, the country has no energy policy to prepare for the inevitable. Is alternative energy our bridge to an oil-free future? After losing $150 million investing in wind energy, Pickens suggests it isn't, not yet. What might get us there? Natural gas. A...

There's an energy revolution happening in villages and towns across Africa -- off-grid solar energy is becoming a viable alternative to traditional electricity systems. In a bold talk about a true leapfrog moment, Amar Inamdar introduces us to proud owners of off-grid solar kits -- and explains how this technology has the opportunity to meet two...

India has a historic opportunity to power its industrialization with clean energy -- and its energy choices will make or break the world's fight against climate change, says clean energy executive, physicist and author Varun Sivaram. Bringing on-the-ground experience as CTO of India's largest renewable energy company, Sivaram proposes a plan for...

In this brief talk, Saul Griffith unveils the invention his new company Makani Power has been working on: giant kite turbines that create surprising amounts of clean, renewable energy.

What would happen if we could generate power from our windowpanes? In this moving talk, entrepreneur Justin Hall-Tipping shows the materials that could make that possible, and how questioning our notion of 'normal' can lead to extraordinary breakthroughs.

Call it "fuel without fossils": Jonathan Trent is working on a plan to grow new biofuel by farming micro-algae in floating offshore pods that eat wastewater from cities. Hear his team's bold vision for Project OMEGA (Offshore Membrane Enclosures for Growing Algae) and how it might power the future.

Africa needs new energy sources to fuel its development, but the continent should invest in renewable energy instead of cheap, polluting alternatives like coal, says climate inclusion activist Chibeze Ezekiel. He tells the story of how he worked with local communities in Ghana to halt the construction of the country's first coal power plant -- a...

Buildings are bad news for the climate -- but they don't have to be. While our structures are currently responsible for a third of global energy consumption and emissions, a future where they create more energy than they consume is possible. Energy policy analyst Ksenia Petrichenko has a three-tiered strategy for thinking differently about build...

In this intimate talk filmed at TED's offices, energy innovator Amory Lovins shows how to get the US off oil and coal by 2050, $5 trillion cheaper, with no Act of Congress, led by business for profit. The key is integrating all four energy-using sectors—and four kinds of innovation.

When the world goes fully electric, what happens to the cars, tools and livelihoods that rely on fossil fuels? Civil engineer and environmental sociologist Emily Grubert visualizes what a clean energy future will look like, outlining the considerations everyone needs to undertake now as the critical, decades-long transition begins.

What's a proven way to lower your energy costs? Would you believe: learning what your neighbor pays. Alex Laskey shows how a quirk of human behavior can make us all better, wiser energy users, with lower bills to prove it.

"It's easy to go through life using energy every day while knowing next to nothing about it," says journalist Jordan Wirfs-Brock. She wants us to reconnect, to understand how energy drives our world: "Energy makes everything we do possible, yet we treat it as an insignificant other." In an energetic talk, Wirfs-Brock shows us the four things we ...

Meet the fantastically colorful and astonishingly adaptable sea slugs that found a way to photosynthesize (or create energy from sunlight) like plants. Diving deep into these often overlooked creatures, invertebrate zoologist Michael Middlebrooks introduces the solar-powered slugs that lost their shells -- but gained the ability to directly harn...

In a series of stunning aerial photographs, Jamey Stillings presents his work documenting how renewable energy projects have shaped (and reshaped) the landscape -- from a solar plant in California to mining projects in the Atacama Desert of Chile.

What's the key to using alternative energy, like solar and wind? Storage -- so we can have power on tap even when the sun's not out and the wind's not blowing. In this accessible, inspiring talk, Donald Sadoway takes to the blackboard to show us the future of large-scale batteries that store renewable energy. As he says: "We need to think about ...

Sometimes the solutions to our biggest challenges don't have to be gigantic investments. Gianluca Ambrosetti describes a solar generator made of mostly everyday materials like mirrors, concrete, and aluminum foil that might actually change the way the world functions today.

All around the world, millions of people are flipping a switch, plugging in, and pressing an 'on' button every second. So how much electricity does humanity use? And how much will we need in the future? Discover how much energy it takes to power the world, and how clean energy sources could help revolutionize our electricity supply. [Written by ...

Stretching over roughly nine million square kilometers and with sands reaching temperatures of up to 80° Celsius, the Sahara Desert receives about 22 million terawatt hours of energy from the Sun every year. That's well over 100 times more energy than humanity consumes annually. So, could covering the desert with solar panels solve our energy pr...

Deep beneath your feet is a molten ball of energy the same temperature as the surface of the sun -- an immense clean energy source that could power the world thousands of times over, says technologist and climate activist Jamie C. Beard. How do we tap it? She lays out a surprising solution, and an unlikely alliance, to harvest geothermal energy ...

While the weather in Iceland is often cold, wet, and windy, a nearly endless supply of heat bubbles away below the surface. In fact, almost every building in the country is heated by geothermal energy in a process with virtually no carbon emissions. So how exactly does this renewable energy work? Jean-Baptiste P. Koehl explores the two primary m...

Every 24 hours, wind generates enough kinetic energy to produce roughly 35 times more electricity than humanity uses each day. And unlike coal or oil, this resource is totally renewed each day. So how can we harness this incredible amount of energy, and is it possible to create a world powered entirely by wind? Rebecca Barthelmie and Sara Pryor ...

What will it take to power the planet in a way that doesn't hurt it? Chris Roe, Amazon's director of energy and sustainable operations, shares the company's pledge to get to net-zero carbon and fully operate all buildings -- including data and distribution centers, warehouses, commercial offices and grocery stores -- on 100-percent renewable ene...

Every month, millions of Americans face an impossible choice: pay for energy to power their homes, or pay for basic needs like food and medicine. TED Fellow DeAndrea Salvador is working to reduce energy costs so that no one has to make this kind of decision. In this quick talk, she shares her plan to help low-income families reduce their bills w...

Nuclear power: the energy crisis has even die-hard environmentalists reconsidering it. In this first-ever TED debate, Stewart Brand and Mark Z. Jacobson square off over the pros and cons. A discussion that'll make you think -- and might even change your mind.

It's so obvious that it's practically proverbial: you can't unboil an egg. But actually, it turns out that you can -- sort of. Eleanor Nelsen explains the process by which mechanical energy can undo what thermal energy has done. [Directed by Província Studio, narrated by Addison Anderson].

Kirk Sorensen shows us the liquid fuel thorium reactor -- a way to produce energy that is safer, cleaner and more efficient than current nuclear power.

Juan Enriquez challenges our definition of bioenergy. Oil, coal, gas and other hydrocarbons are not chemical but biological products, based on plant matter -- and thus, growable. Our whole approach to fuel, he argues, needs to change.

Perpetual motion machines — devices that can do work indefinitely without any external energy source — have captured many inventors' imaginations because they could totally transform our relationship with energy. There's just one problem: they don't work. Why not? Netta Schramm describes the pitfalls of perpetual motion machines. [Directed by TE...