ChuChu TV, the company responsible for some of the most widely viewed toddler content on YouTube, has a suitably cute origin story. Vinoth Chandar, the chief executive, had always played around on YouTube, making Hindu devotionals and little videos of his father, a well-known Indian music producer. But after he and his wife had a baby daughter, whom they nicknamed “Chu Chu”, he realised he had a new audience – of one. He drew a Chu Chu-like character in Flash, the animation program, and then created a short video of the girl dancing to the popular and decidedly unwoke Indian nursery rhyme Chubby Cheeks. (Curly hair, very fair / Eyes are blue, lovely too / Teacher’s pet, is that you?)
Chu Chu loved it. “She wanted me to repeat it again and again,” Chandar recalls. Which gave him an idea: “If she is going to like it, the kids around the world should like it.” He created a YouTube channel and uploaded the video. In a few weeks, it had 300,000 views. He made and uploaded another video, based on Twinkle, Twinkle, Little Star, and it took off. After posting just two videos, he had 5000 subscribers to his channel. Someone from YouTube reached out and, as Chandar remembers it, said, “You guys are doing some magic with your content.” So Chandar and several of his friends formed a company in Chennai, in the South Indian state of Tamil Nadu, from the bones of an IT business they’d run. They hired a few animators and started putting out a video a month.
Five years on, ChuChu TV is a fast-growing threat to traditional competitors, from Sesame Street to Disney to Nickelodeon. With all its decades of episodes, well-known characters and worldwide brand recognition, Sesame Street has more than 5 billion views on YouTube. That’s impressive, but ChuChu has more than 19 billion. Sesame Street’s main feed has 4 million subscribers; the original ChuChu TV channel has 19 million – placing it among the top 25 most watched YouTube channels in the world, according to the social-media-tracking site Social Blade – and its subsidiary channels (primarily ChuChu TV Surprise Eggs Toys and ChuChu TV Español) have another 10 million.
The ‘algorithm is a myth’
According to ChuChu, its two largest markets are the United States and India, which together generate about one-third of its views. But each month, tens of millions of views also pour in from Britain, Canada, Mexico, Australia and all over Asia and Africa. Roughly 20 million times a day, a caretaker somewhere on earth fires up YouTube and plays a ChuChu video. What began as a lark has grown into something very, very big, inflating the company’s ambitions. “We want to be the next Disney,” Chandar told me.
But whereas Disney has long mined cultures around the world for legends and myths – dropping them into consumerist, family-friendly American formats – ChuChu’s videos are a different kind of hybrid: the company ingests Anglo-American nursery rhymes and holidays, and produces new versions with subcontinental flair. The characters’ most prominent animal friend is a unicorn-elephant. Nursery rhymes become music videos, complete with Indian dances and iconography. Kids of all skin tones and hair types speak with an Indian accent.
Many observers respond to ChuChu’s unexpected success by implying that the company has somehow gamed the system. “Whenever we go to the US,” Chandar told me, “people say, ‘You guys cracked the algorithm.’ But we didn’t do anything. The algorithm thing is a complete myth.”
ChuChu does not employ the weird keyword-stuffed titles used by lower-rent YouTube channels. The company’s titles are simple, sunny, consistent. Its theory of media is that good stuff wins, which is why its videos have won. “We know what our subscribers want, and we give it to them,” Chandar says. ChuChu says it adds roughly 40,000 subscribers a day.
That kind of growth suggests that something unpredictable and wild is happening: America’s grip on children’s entertainment is coming to an end. ChuChu is but the largest of a new constellation of children’s-media brands on YouTube that is spread out across the world: Little Baby Bum in London, Animaccord Studios in Moscow, Videogyan in Bangalore, Billion Surprise Toys in Dubai, TuTiTu TV in Tel Aviv, and LooLoo Kids in Iași, a Romanian town near the country’s border with Moldova. The new children’s media look nothing like what we adults would have expected. They are exuberant, cheap, weird, and multicultural. YouTube’s content for young kids – what I think of as Toddler YouTube – is a mishmash, a bricolage, a trash fire, an explosion of creativity. It’s a largely unregulated, data-driven grab for toddlers’ attention, and, as we’ve seen with the rest of social media, its ramifications may be deeper and wider than you’d initially think.
With two small kids in my own house, I haven’t been navigating this new world as a theoretical challenge. My youngest, who is two years old, can rarely sustain her attention to watch the Netflix shows we put on for my five-year-old son. But when I showed her a ChuChu video, just to see how she’d react, I practically had to wrestle my phone away from her. What was this stuff? Why did it have the effect it did?
To find out, I had to go to Chennai.
Uber in Chennai is essentially the same as Uber in Oakland, California, where I live. In the airport I hit a button on my phone, and soon a white sedan pulls up outside. My driver is a student who has come to Chennai to break into Tollywood. Yes, Tollywood: T for Telugu, the language spoken by 75 million people, mostly in South India.
The driver drops me off just south of the city centre, in an area of new high-rises that overlook Srinivasapuram, a fishing village on the Bay of Bengal. The village hangs on to the edge of the city, which has been modernising fast; the government has been trying to relocate the village for years. From my hotel, I watch tiny figures wander over to the Adyar River estuary and squat, staring up at the opulence of the new Chennai.
ChuChu’s headquarters takes up the entire first floor of a blue-glass building with bright-yellow stripes. Rows of animators flank a centre aisle that houses big, colourful flourishes – weird chairs, structural columns with graffiti on them – signifying “fun tech office!” The work floor is ringed by maybe 10 offices that house the higher-ups. ChuChu says it employs about 200 people.
Chandar meets me and leads me into a massive conference room. In addition to being the chief executive, he composes music for ChuChu. He’s the public face of the company and, at 39, a few years younger than the other four founders, who each hold an equal stake. He sends a young man to get me a coffee, and then we sit down together with his friend B.M. Krishnan, a former accountant and a ChuChu co-founder who is now the company’s chief creative officer.
It was after Krishnan joined the creative team, Chandar tells me, that ChuChu really began to achieve global popularity. What made the difference, in part, was that Krishnan decided to rewrite nursery rhymes that he felt didn’t end well or teach good morals. What if Jack and Jill, after falling down while fetching the pail of water, get back up, learn from the resilience of birds and ants, actually get the damn pail of water, and give it to their mum? “It was ‘Jack and Jill 2.0,’ ” Chandar says. “I thought, This is how a nursery rhyme should be.”
After Krishnan rewrote a nursery rhyme, Chandar would then take the lyrics and compose music around them. The songs are simple, but if you hear them once, you will hear them for the rest of your life. Krishnan would storyboard the videos, imagining the sequence of shots, as befitting his youthful dream of becoming a movie director. ChuChu productions are essentially music videos for kids, sometimes featuring Tollywood dance moves that Chandar and Krishnan demonstrate for the animators.
The ChuChu guys didn’t set out to make educational programming. They were just making videos for fun. How were they to know they’d become a global force in children’s entertainment? As time went on and the staff expanded, the company created a teaching series, called Learning English Is Fun, and worked with a preschool company to develop an app, ChuChu School, that has an explicitly didactic purpose. But generally speaking, Chandar and Krishnan just wanted their videos to be wholesome – to deliver entertainment that perhaps provided kids with a dose of moral instruction.
Krishnan had no experience other than his own parenting. But if whatever he did as a parent worked for his kids, he felt, why wouldn’t it work for everyone? For example, when he taught his kids left from right, he liked to do it in the car, when they were in the back seat. That way, if he pointed left, it was left for them, too. So when ChuChu made a video teaching the left-right concept, it made sure to always show the characters from behind, not mirrored, so that when a character pointed left, the kids watching would understand.
As it became clear that ChuChu videos were being watched by millions of people on six continents, Krishnan and Chandar started branching out into original songs and nursery rhymes, which Krishnan has been writing for the past couple of years. Their content runs the gamut, from an adaptation of Here We Go Round the Mulberry Bush, dedicated to tree planting as a way to fight global warming, to Banana Song (“Na na na banana / long and curved banana”).
But their most popular video, by far, is a compilation that opens with Johny Johny Yes Papa, a take on a nursery rhyme popular in India. With 1.5 billion views, it’s one of the most watched videos of any kind, ever.
In it, a small boy wakes up in the middle of the night and sneaks to the kitchen. He grabs a jar of sugar; just as he’s spooning some into his mouth, the light switches on, and his father walks in.
As the son laughs, the song kicks up, and all the kids in the family play and dance together.
When Krishnan watches Johny Johny, he sees a universal father-child interaction. The kid tries to get one over on the dad, and when the dad catches him, the parent isn’t actually annoyed. Instead, he’s almost delighted by the sly willfulness. “Inside, the father will be a little happy,” Krishnan says. “This child is having some brains.”
ChuChu and companies like it can see exactly what holds a toddler’s attention, moment by moment, and what causes it to drift.
To an adult, the appeal of ChuChu videos is not totally obvious. On the one hand, the songs are catchy, the colours are bright, and the characters are cute. On the other, the animation is two-dimensional and kind of choppy, a throwback to the era before Pixar. And there is a lot of movement; sometimes every pixel of the screen seems to be in motion. Krishnan and Chandar believe that any given shot needs to include many different things a child could notice: A bird flying in the background. Something wiggling. These things hold kids’ attention.
The men know this with quantitative precision. YouTube analytics show exactly when a video’s audience falls off. ChuChu and other companies like it – whatever their larger philosophy – can see exactly what holds a toddler’s attention, moment by moment, and what causes it to drift. If a video achieves a 60 per cent average completion rate, ChuChu knows it has a hit. Using these data doesn’t let it “crack the algorithm”; everyone has access to a version of these numbers. Instead, Chandar uses the analytics to tune his and other creators’ intuition about what works.
But what people want changes. As YouTube became the world’s babysitter – an electronic pacifier during trips, or when adults are having dinner – parents began to seek out videos that soaked up more time. So nowadays what’s most popular on Toddler YouTube are not three-minute songs, but compilations that last 30 to 45 minutes, or even longer.
ChuChu learns many lessons from parents, who provide the company with constant feedback. It heard from parents who questioned the diversity of its characters, who were all light-skinned; it now has two light-skinned and two dark-skinned main characters. It heard from parents who wondered about the toy guns in one video; it removed them. It heard from parents about an earlier version of the Johny Johny video, in which the little boy sleeps in a communal bed with his family, as is common in India; in a new version, he has his own room.
ChuChu is largely making things up as it goes, responding – as any young company would – to what its consumers want. Despite the company’s earnest desire to educate the kids who watch its videos, it has not tried to use the lessons generated by previous generations of educational-TV makers. Its executives and developers don’t regularly work with academics who could help them shape their content to promote healthy development of young brains. So what effects are ChuChu’s shows having on kids? How does what it’s producing compare with whatever kids were watching before?
Television’s free fall
Part of the absurdity of the internet is that these questions get asked only after something metastasises and spreads across the world. But children’s content reflects its time, and this is how we live.
Fifty years ago, the most influential children’s-television studio of the 20th century, Children’s Television Workshop, came into being, thanks to funding from the Ford Foundation, the Carnegie Corporation of New York, and the United States government. It created an unprecedented thing – Sesame Street – with help from a bevy of education experts and Jim Henson, the creator of The Muppets. The cast was integrated. The setting was urban. The show was ultimately broadcast on public television across America, defining a multicultural ideal at a time of racial strife. It was the preschool-media embodiment of the War on Poverty, a national government solution to the problems of America’s cities.
The 1990s and 2000s saw the growth of cable TV channels targeted at children. With the rise of ubiquitous merchandising deals and niche content, powerful American media companies such as Disney, Turner and Viacom figured out how to make money off young kids. They created, respectively, the Disney Channel, the Cartoon Network and, of course, Nickelodeon, which was the most watched cable channel during traditional television’s peak year: 2009-10 (Nielsen’s measurement period starts and ends in September). Since then, however, little kids have watched less and less television; as of last spring, ratings in 2018 were down a full 20 per cent from just last year. As analysts like to put it, the industry is in free fall. The cause is obvious: more and more kids are watching videos online.
This might not exactly seem like a tragedy. After all, Americans watch a lot of TV. By the time Nielsen began recording how much time Americans spent in front of TV screens in 1949-50, each household was already averaging four hours and 35 minutes a day. That number kept going up, passing six hours in 1970-71, seven hours in 1983-84, all the way up to eight hours in 2003-04. Viewing finally peaked at eight hours and 55 minutes in 2009-10. Since then, the numbers have been gliding downwards, with the most recent data showing Americans’ viewing habits edging under eight hours a day for the first time since George W. Bush’s presidency.
Given this baseline, perhaps it’s fine that phones – and YouTube specifically – are spooning some number of hours from TV. Considered purely as a medium, television seems to have little to recommend it over YouTube. But that would ignore the history of children’s television, which is one of those 20th-century triumphs that people take for granted.
Creative and educational TV
The institutions of the 20th century shaped television into a tool for learning. Researchers, regulators and creators poured tremendous resources into producing a version of children’s TV that, at the very least, is not harmful to kids and that has even been shown to be good for them under the right conditions.
At first, pretty much everybody agrees, television for kids was bad – dumb cartoons, cowboy shows, locally produced slop. There also wasn’t much of it, so kids often watched whatever adult programming was on TV. In the early 1950s, one teacher enumerated the changes she’d seen in her pupils since they had “got television”: “They have no sense of values, no feeling of wonder, no sustained interest. Their shallowness of thought and feeling is markedly apparent, and they display a lack of co-operation and inability to finish a task.” There were calls for action.
Congress held hearings on television’s possible deleterious effects on children (and adults) in 1952, 1954 and 1955. But not much happened, and the government and TV networks generally settled into a cycle that has been described by the media scholar Keisha Hoerrner. “First,” she has written, “the government castigated the industry for its deplorable programming, then the industry took its verbal punishment and promised to do better, followed by the government staying out of the industry’s business.”
Without substantive oversight by regulators, in the late 1960s the calls for change entered a new, more creative phase. A group calling itself Action for Children’s Television began advocating for specific changes to programming for young kids. The Corporation for Public Broadcasting was formed in 1968 with government dollars. At the same time, Children’s Television Workshop began producing Sesame Street, and the forerunner to PBS, National Educational Television, began distributing Mister Rogers’ Neighbourhood. These shows were tremendously successful in creating genuinely educational television. By the time children’s programming got swept up into the growing cable industry, the big channels had learned a lot from the public model, which they incorporated into shows such as Dora the Explorer and Blue’s Clues.
Add all these factors up, and a surprising thing is revealed: through the sustained efforts of children’s-TV reformers, something good happened. “Basic scientific research on how children attend to and comprehend television has evolved into sophisticated studies of how children can learn from electronic media,” a literature review by the Kaiser Family Foundation concluded. “This, in turn, has led to the design and production of a number of effective educational television programs, starting with Sesame Street, which many experts regard as one of the most important educational innovations of recent decades.”
Among the specific findings, researchers demonstrated that Sesame Street improved children’s vocabulary, regardless of their parents’ education or attitudes. Another study found that regular adult TV stunted vocabulary development, while high-quality educational programs accelerated language acquisition. The most fascinating study began in the 1980s, when a University of Massachusetts at Amherst team installed video cameras in more than 100 homes, and had those families and hundreds of others keep a written log of their media diet. Following up more than a decade later, researchers found that “viewing educational programs as preschoolers was associated with higher grades, reading more books, placing more value on achievement, greater creativity and less aggression”. On the flip side, violent programming led to lower grades among girls, in particular. The team was unequivocal about the meaning of these results: what kids watched was much more important than how much of it they watched. Or, as the researchers’ refutation of Marshall McLuhan’s famous aphorism went, “The medium is not the message: the message is.”
So what message are very young kids receiving from the most popular YouTube videos today? And how are those children being shaped by the videos?
To explore this question, I sought out Colleen Russo Johnson, a co-director of UCLA’s Centre for Scholars and Storytellers. Johnson did her doctoral work on kids’ media and serves as a consultant to studios that produce children’s programming. I asked her to watch Johny Johny Yes Papa and a few other ChuChu videos and tell me what she saw.
Her answer was simple: “Bright lights, extraneous elements and faster pacing.” In one of the videos I had her watch, a little boy dances flanked by two cows on a stage. A crowd waves its hands in the foreground. Lights flash and stars spin in the background. The boy and the cows perform Head, Shoulders, Knees and Toes, and as they do, the dance floor lights up, à la Saturday Night Fever. Johnson told me all that movement risks distracting kids from any educational work the videos might do.
For kids to have the best chance of learning from a video, Johnson told me, it must unfold slowly, the way a book does when it is read to a child. “Calmer, slower-paced videos with less distracting features are more effective for younger children,” she said. “This also allows the video to focus attention on the relevant visuals for the song, thus aiding in comprehension.”
To be clear, it’s hard to make videos that very young children can learn from. (Johnson’s doctoral adviser, Georgene Troseth, was part of the team that demonstrated this.) Children under two struggle to translate the world of the screen to the one they see around them, with all its complexity and three-dimensionality. That’s why things like Baby Einstein have been debunked as educational tools. Most important for kids under two is rich interaction with humans and their actual environments. Older toddlers are the ones who can get something truly educational from videos, as opposed to just entertainment and the killing of time.
But even in relatively limited doses, these videos can affect young toddlers’ development. If kids watch a lot of fast-paced videos, they come to expect that that is how videos should work, which could make other educational videos less compelling and effective. “If kids get used to all the crazy, distracting, superfluous visual movement, then they may start requiring that to hold their attention,” Johnson says.
ChuChu has changed over time – it has slowed the pacing of its videos, focused on the key elements of scenes, and made more explicitly educational videos. But in the wilds of YouTube, the videos with the most views, not the most educational value, are the ones that rise to the top. ChuChu’s newer videos, which have more of the features Johnson looks for, have not had the time to hoover up as much attention, so the old ones keep appearing in YouTube searches and suggestions.
Not to put too fine a point on it, but this is almost precisely the problem that the rest of the media world finds itself in. Because quality is hard to measure, the numbers that exist are the ones that describe attention, not effect: views, watch time, completion rate, subscribers. YouTube uses those metrics, ostensibly objectively, when it recommends videos. But as Theodore Porter, the great historian of science and technology, put it in his book Trust in Numbers, “Quantification is a way of making decisions without seeming to decide.”
In a widely circulated essay last year, the artist James Bridle highlighted the many violent, odd and nearly robotic children’s videos sitting in the vaults of YouTube. They didn’t seem made by human hands, he wrote, or at least not completely. Some were sadistic or sick. (After Bridle’s essay was published, YouTube undertook an effort to purge the site of “content that attempts to pass as family-friendly, but clearly is not”, and ultimately removed some of the disturbing videos the essay cited.) Others seemed like grab bags of keywords that had been successful for more professional operations: nursery rhymes, surprise eggs, finger family, learning colours. These were videos reverse engineered from whatever someone might enter into the YouTube search box. And though none of these videos has achieved the scale of ChuChu’s work, they definitely get seen, and are occasionally recommended to a child who has been happily watching something more virtuous.
The world of YouTube is vastly different from the world of broadcast television. While broadcasters in the United States and abroad are bound by rules, and the threat of punishment for breaking those rules, far fewer such regulations apply to the creators of YouTube content, or to YouTube itself. YouTube’s default position is that no one under 13 is watching videos on its site – because that’s the minimum age allowed under its terms of service. In addition to its main site, however, the company has developed an app called YouTube Kids. Like normal YouTube, it plays videos, but the design and content are specifically made for parents and children. It’s very good. It draws on the expertise of well-established children’s-media companies. Parents can restrict their children’s viewing in a multitude of ways, such as allowing access only to content handpicked by PBS Kids. But here’s the problem: just a small fraction of YouTube’s 1.9 billion monthly viewers use it. (YouTube Kids is not available in as many countries as normal YouTube is.)
Little kids are responsible for billions of views on YouTube – pretending otherwise is irresponsible. In a small study, a team of paediatricians at Einstein Medical Centre, in Philadelphia, found that YouTube was popular among device-using children under the age of two. Oh, and 97 per cent of the kids in the study had used a mobile device. By age four, 75 per cent of the children in the study had their own tablet, smartphone or iPod. And that was in 2015. The sea change in children’s content that ChuChu and other new video makers have effected is, above all, profitable.
To date, YouTube has hidden behind a terms-of-service defence that its own data must tell it is toothless. There don’t seem to be any imminent regulatory solutions to this; by and large, YouTube regulates itself. The company can declare its efforts for children sufficient at any point.
But there is something the company could do immediately to improve the situation. YouTube knows that I – and tens of millions of other people – have watched lots of videos made for toddlers, but it has never once recommended that I switch to YouTube Kids. Think of how hard Facebook works to push users from Instagram onto Facebook and vice versa. Why not try to get more families onto the YouTube Kids app? (Malik Ducard, YouTube’s global head of family and learning, said in a statement that YouTube has “worked hard to raise awareness of the YouTube Kids app through heavy promotion. These promos have helped drive our growth. Today, YouTube Kids has over 14 million weekly viewers and over 70 billion views.”)
Safer space for kids
If streaming video followed the broadcast model, YouTube – in partnership with governments around the world – could also subsidise research into creating educational content specifically for YouTube, and into how best to deliver it to children. The company could invest in research to develop the best quantitative signals for educational programming, so it could recommend that programming to viewers its algorithm believes to be children. It could fund new educational programming, just as broadcasters have been required to do for decades. (“We are always looking for ways to build the educational content offering in the app in a way that’s really fun and engaging for kids,” Ducard said.)
Other, more intense measures could help, too. For example, how about restricting toddler videos to the YouTube Kids app? Toddler content could, in effect, be forbidden on the main platform. If video makers wanted their work on the YouTube Kids app, they’d have to agree to have it only on the Kids app. This might hurt their view counts initially, but it would keep kids in a safer environment, and in the long term would protect the brand from the inevitable kid-related scandals. The issue of inappropriate videos popping up in YouTube Kids has received a good deal of national press – but society can live with a tiny sliver of bad things slipping through the company’s filters. It’s a small issue compared with kids watching billions of videos on regular YouTube. Why worry about the ways a kid could hurt himself in a padded room, when huge numbers of kids are tromping around the virtual city’s empty lots? (Ducard said that YouTube knows families watch videos together: “That’s why this content is available on our main YouTube site and also on our YouTube Kids app.”)
Maybe better or more refined solutions exist, but if the history of children’s television teaches us anything, it’s that the market alone will not generate the best outcomes for kids. Nor is the United States government likely to demand change, at least not without prompting. Heroes will have to emerge to push for change in the new YouTube’d world, just as they did in the early days of broadcast children’s TV. And not all of those heroes will come from the Western world. They’ll come from all over the globe, maybe even Chennai.
Watching my daughter play with my phone is a horrifying experience, precisely because her mimicry of adult behaviours is already so accurate. Her tiny fingers poke at buttons, pinch to zoom, endlessly scroll. It’s as though she’s grown a new brain from her fingertips. Most parents feel some version of this horror. Watching them poke and pinch at our devices, we realise that these rectangles of light and compulsion are not going away, and we are all dosing ourselves with their pleasures and conveniences without knowing the consequences.
It took energy and institutional imagination to fix TV for kids. Where will that come from today? Who will pay for the research and, later, the production? How would or could YouTube implement any kind of blanket recommendation?
I worry about these questions a lot, and I wonder if our 21st-century American institutions are up to the challenges they’ve created with their market successes and ethical abdications. Even so, when I visited Chennai, I felt OK about the media future we’re heading into. The toddler videos that ChuChu is posting on YouTube are cultural hybrids, exuberant and cosmopolitan, and in a philosophical sense they presuppose a world in which all children are part of one vast community, drawing on the world’s collective heritage of storytelling. That’s a rich narrative rootstock, with lots of lessons to teach – and right now who’s better poised to make the most of it than ChuChu and companies like it, especially if they can learn from the legacy of American educational TV?
ChuChu’s founders aren’t blind to the power of new-media platforms, or the undertow of crappy YouTube producers, or the addictive power of devices, but the magnitude and improbability of their success more than balance the scales. They don’t quite seem to know why (or how, exactly) they’ve been given this opportunity to speak to millions from an office in South India, but they’re not going to throw away the chance. After all, there are so many stories to tell.
On my last day in the ChuChu offices, Krishnan related a parable to me from the Mahābhārata, a Sanskrit epic. A prince wants to be known as generous, so the god Krishna decides to put him to the test: he creates two mountains of gold and tells the prince to give it all away in 24 hours. The prince begins to do so, parceling it out to people he thinks need it. But as the day ends he’s hardly made a dent in the mountains. So Krishna calls another prince and tells him he has just five minutes to give away the gold. This prince sees two people walking along, goes right over to them, and gives each a mountain. Just like that, the job is done. The moral is unsettling, but simple: don’t impose limits on your generosity.
Krishnan loves this parable. “This is a story which I can do for ChuChu,” he told me. “But with pizza.”
Alexis C. Madrigal is a staff writer at The Atlantic. He’s the author of Powering the Dream: The History and Promise of Green Technology.