Excerpt: Taming the Sun

Return to Taming the Sun.

Chapter One: Two Futures

The year is 2050, and the world is more polluted, unequal, and dangerous than ever. Megacities like New Delhi, Mexico City, and Lagos are suffocated by smog. More than a billion people around the world still lack access to reliable electricity. And climate change is serving up droughts, floods, and heat waves with alarming regularity.

The trouble is that fossil fuels continue to exert a stranglehold on the global economy. Coal and natural gas are still burned to produce most of the world’s electricity and run most of its factories, spewing carbon dioxide and other climate-warming gases into the atmosphere. And oil still fuels a majority of cars and trucks, as well as almost every single airplane and ship on the planet, further polluting the air.

Much of this disastrous state of the world is a result of the solar power revolution sputtering out. Way back in 2016, solar photovoltaic (PV) panels, which convert sunlight into electricity, became the cheapest source of electricity on the planet. Experts breathlessly prophesied that it was only a matter of time before solar PV dethroned fossil fuels—a bold claim for a technology that supplied less than 1 percent of the world’s energy needs.

For a time, those rosy projections were vindicated. Over the next two decades, solar PV would soar in popularity. In developed countries, new homes came with sleek solar roofs, and in the poorest corners of the developing world, stand-alone solar systems gave millions of villagers with no connection to an electricity grid their first taste of modern energy. From Chile to China, more solar farms—vast fields of PV panels—sprouted than all other types of power plants combined. And as producers—mostly in Asia—churned out silicon-based panels year after year, they got better at shaving the technology’s costs.

But sometime in the 2030s, solar’s once-unstoppable growth slowed, leaving it far short of dethroning fossil fuels. Markets around the world saturated as demand for additional solar power dried up. On its face, this stagnation was puzzling: if solar PV kept getting cheaper, widening its competitive lead over fossil fuels, why did its expansion slow?

Part of the problem was that even as the cost of producing electricity from solar PV fell, the value of that electricity—the amount that a utility, for instance, was willing to pay for it to then send via the grid to meet the needs of homes and businesses—decreased even faster. The value diminished because a power source tied to unreliable sunshine quickly becomes a nuisance as it grows. PV panels produce power only when they receive sunlight, so nightfall (or even a passing cloud) can sideline them. Even before 2020, this intermittency caused problems in some regions that were early solar adopters. In California, for example, solar PV quickly rose to meet most of the state’s power needs around lunchtime, when the sun was overhead. But then, adding a new solar panel, no matter how cheap, was worthless because when the state needed power—at dinnertime—the sun was setting. As a result, the gently declining cost of existing silicon solar PV technology was soon overtaken by the swift erosion of the value of the power the panels could produce.

Some countries—especially those that raced ahead to deploy solar PV projects—recognized that solar’s value was in decline. But they were confident that lithium-ion batteries, which were also getting cheaper alongside PV panels, would come to the rescue. The falling cost of these batteries did indeed make it feasible to store some of the unused daytime solar power for later in the evening. Batteries, though, were not the panacea that many expected. It made economic sense to use them to store power for a few hours; but they were too expensive to use for smoothing out the day-to-day variations in solar PV output and certainly for handling the biggest energy storage need: squirreling away surplus solar energy from sunny months for use in gloomier ones.

Solar PV’s growth also slowed because countries, especially in the developing world, failed to build out their electricity grids to keep up with the deployment of solar power. For example, India struggled to connect solar farms in distant deserts to its thirsty megacities. And when the government shifted focus to deploying solar panels on building rooftops, ramshackle urban grids buckled under the strain of absorbing sudden surges of solar power.

Having leveled off, solar’s contribution to the world’s energy needs is respectable but limited today, at the mid-century mark. With the exception of wind power, other clean energy sources have not stepped in to pick up much of the slack. Wind power’s rise has mirrored that of solar PV, and the two sister sources of renewable energy jointly produce a third of the world’s electricity. But like solar PV, wind power is unreliable, so it too faces limits on its deployment.

More reliable sources of clean energy have disappointed. Nuclear power—politically radioactive—has declined from its glory days in the twentieth century to just a few remaining reactors in Asia today. New hydropower dams are just as unpopular. And various other potential clean energy sources—from geothermal to tidal power—remain mostly on the drawing board. As a result, the world still depends on fossil fuels to meet most of its electricity needs.

On top of this, many of the world’s energy needs don’t involve using electricity. Those needs are met almost exclusively by fossil fuels, and they have only grown as emerging economies have industrialized, with staggering consequences. Industrial facilities, like cement and steel plants, belch out soot from burning coal. Skyrocketing demand for transportation has also defiled the air and caused crippling congestion. Although fewer people own cars today than in decades past thanks to fleets of autonomous vehicles and convenient ridesharing, these advances have made it easier and cheaper than ever to get around; the resulting surge in travelers has packed more cars on the road at any given time.

Many had hoped that electric vehicles might reduce local air pollution, and indeed they have risen to lead the pack in new vehicle sales. But over 1 billion petroleum-fueled cars and trucks still share the road with electric vehicles; and supposedly clean electric vehicles actually cause substantial pollution every time they charge up with electricity generated by fossil-fueled power plants. As a result, two-thirds of humanity face toxic air in miserable metropolises, in which global elites try to spend as little time as possible.

This would all be bad enough, but scientists predict it will only get worse because the cumulative carbon emissions from burning all those fossil fuels have set irreversible climate shifts in motion. It seems laughable that way back in 2015, countries around the world signed the Paris Climate Change Agreement, committing in all seriousness to limit global warming to 2°C. Just fifteen years later, those countries had already pumped enough greenhouse gases into the atmosphere to guarantee at least such a temperature rise.

Climate change has already taken a toll around the world. Rising sea levels have spurred waves of mass migration from the floodplains of Bangladesh. Ocean acidification has decimated fisheries from Norway to Nicaragua. Droughts across Africa and the Middle East have left hundreds of millions in a persistent state of famine and water scarcity; Egypt has just declared war on Ethiopia for choking off its supply from the parched Nile river.

Far from interceding, the United States has turned inward from the crumbling world order to weather superstorms on the Atlantic seaboard and extinguish the wildfires perpetually raging in the west. But the worst is yet to come. Miami and New Orleans will be underwater before the century is out. New York will be the new Bahrain of heatwaves. For climate change is actually speeding up. The white ice sheets at the globe’s poles have largely disappeared, leaving only darker ocean water that reflects less sunlight away and warms the Earth’s surface even faster. Vast stores of greenhouse gases, once trapped by permafrost that has since melted, are escaping into the atmosphere from Siberia and the bottom of the ocean. Like a runaway train, the changing climate can’t be stopped. Not now, nor for the next 10,000 years.

Belated international efforts to drastically curb global emissions have stalled. Emergency negotiations at the United Nations over a global carbon tax don’t stand a chance of finding common ground among bickering blocs. A corporate coalition of fossil fuel majors and heavy industries adamantly opposes what it calls draconian proposals to leave fossil fuels in the ground, arguing to great political effect that doing so would further impoverish the developing world. While the political theater has played out, entire countries—including the Marshall Islands, Tuvalu, and Fiji—have been swallowed whole by the Pacific Ocean.

The time for decisive action is long past. With the benefit of hindsight, it is increasingly clear that the meteoric growth in solar power lulled governments into false confidence before their rude awakening to the solar slowdown. They left the transition to clean energy on autopilot. Had they instead made a small course correction in those early days—by planning for, and investing in, the future—today’s gloomy outlook might have been avoided.

A Brighter Future

The year is 2050; despite facing grave challenges, the world still controls its destiny. Nightmare scenarios of economic and humanitarian catastrophe—toward which the planet once hurtled—are off the table. The climate is undeniably changing, but at a manageable pace that has allowed countries to adapt. Now, the foremost priority of governments around the world is to find fulfilling employment for a global population of 10 billion in the era of artificial intelligence and the data economy.

The dramatic rise of clean energy has prevented climate change from spiraling out of control—and in the process powered economic growth and lifted the world’s destitute out of darkness. For the first time in history, fossil fuels are on the wane. A dwindling number of plants still burn coal and natural gas to produce electricity and run factories, but their carbon emissions get captured and either used in industrial processes or stored deep underground. Oil still fuels a large percentage of global transportation, but that share falls every year as electricity and clean fuels are used instead.

Solar energy is the linchpin of this clean energy revolution. For 3,000 years, civilizations have yearned to harness the sun—an inexhaustible fireball that could power the world’s energy needs thousands of times over. Finally, in recent decades, solar energy has risen relentlessly, clawing market share from fossil fuels. Today, solar supplies a third of global electricity; well before the century is out, most of the world’s energy needs will be met by converting sunlight into electricity, heat, and portable fuels. When that happens, the twenty-first century will be remembered as the one in which humankind finally tamed the sun.

Obviously, today’s solar technologies bear little resemblance to the quaint, silicon-based solar PV panels that China produced back in the opening decades of the twenty-first century. Those PV panels played an important role in establishing solar technology as a feasible source of energy. Their early success also reassured the world’s biggest investors that it was safe to invest in clean energy projects. And they still reliably pump out electricity in some of the world’s oldest solar parks.

But those original PV panels—heavy, ugly, and maxed out in terms of performance—evolved to become lightweight, attractive, and much more efficient at converting sunlight into electricity. By 2030, industrial printers were churning out rolls of solar PV coatings in a range of colors and transparencies. A decade later, solar-coating your house was as cheap as painting it.

Architects rejoiced. Today at the mid-century mark, most urban buildings are wrapped in electricity-generating solar materials that tint the windows, enliven the facade, and shrink the carbon footprint. Nearly free electricity has induced heavy industries to switch from burning fossil fuels to running off solar power. Solar PV isn’t just powering glamorous urban buildings or massive industrial plants; PV materials are now light enough to be supported by flimsy shanty roofs in the slum outskirts of megacities in the developing world. And way outside the cities, even the poorest of the poor can easily afford solar power. Abject energy poverty has been eradicated—nearly every person on the planet has access to some electricity—although much work remains to address energy inequality.

Still, these wondrous solar PV coatings remain at the mercy of unreliable sunlight. Their trivial cost has helped mitigate this concern, making it economical, for example, to unroll a solar PV carpet over vast swathes of California’s Mojave Desert and throw away excess power in the middle of the day. This, in effect, gives rise to a reliable power plant capable of producing a constant amount of electricity from late morning through early evening.

But solar PV still cannot supply California with power once the sun sets. Fortunately, that need has been met by a completely different solar technology that enjoyed a renaissance in the 2020s after analysts prematurely wrote it off as dead. Concentrated solar power plants, which employ armies of mirrors to focus the sun’s rays to generate heat that can run a power plant, have improved dramatically in cost and performance. Most important, they are able to store the heat that they capture to produce power throughout the night. So, in tandem, PV coatings and concentrated solar power plants generate 24/7 electricity for a fraction of the cost of running fossil-fueled power plants.

In recent decades, the term “solar energy” has supplanted “solar power.” That’s because PV and other solar technologies not only generate electric power now, they also produce fuels that can store energy to be used where electricity is less practical. In the mid-2030s, firms began to mass-produce materials to convert sunlight directly into hydrogen fuel. Slowly but steadily, the makeup of the world’s fuel mix has shifted toward clean solar fuels. Just as oil refineries convert crude oil into products like gasoline, jet fuel, and asphalt, so do solar refineries convert hydrogen into liquid fuels for vehicles, ships, and aircraft and into a whole range of other products, from fertilizer to plastics.

Hydrogen itself has become a popular fuel for cars and trucks. Petroleum-fueled vehicles are now a distant third-place choice, behind electric and hydrogen-fueled vehicles, neither of which contribute to local air pollution. As a result, even though urban denizens complain of ever-worsening traffic, air pollution levels peaked in 2040 and have been declining ever since.

Today’s panoply of solar technologies is the result of farsighted decisions made over three decades ago in the public and private sectors to invest in innovation. The United States led this push and has profited handsomely as a result, now that the combined market for solar technologies is bigger than that for petroleum products. Just as America had surged past Saudi Arabia in 2013 to become the world’s biggest oil producer, so too did it dethrone China twenty years later as the leading manufacturer of solar technologies. That was just as well—or else America might have developed a dangerous dependence on imports of Chinese energy products. Instead, the United States managed to achieve prosperity and energy security at the cost of a few billion dollars a year in additional funding for research into and development and demonstration of new technologies—a rounding error on the federal budget.

Solar PV remains the most widespread method of harnessing the sun’s energy even as other technologies, such as solar fuels, rise in popularity. To cope with the massive fluctuations of electricity from solar PV, countries have innovated in the design of their energy systems.

For example, countries have cooperated to build out continent-spanning power grids—the biggest ones are in Asia and North America—that connect solar PV in sun-drenched deserts with power-hungry cities. Not only are grids bigger, but they are smarter. They transmit signals to billions of Internet-connected devices—such as air conditioners, water heaters, and industrial machinery—that adjust their electricity demand on the fly to match the availability of solar PV supply. In addition, they can call upon various options to store intermittently produced solar energy, from batteries to hydropower reservoirs to underground wells. Grids can even intelligently decide when to charge up or draw down the millions of plugged-in electric vehicles that act as mobile batteries to back up solar PV.

Although solar energy has emerged as the star of the energy revolution, every star needs a supporting cast. Wind power has ably supplemented solar, rising steadily during this century. And the renaissance of nuclear power has shored up the supply of reliable electricity after governments around the world braved political headwinds to invest in a new generation of safer, cheaper reactors. Seeing the writing on the wall, fossil fuel companies have done their part as well, lavishly funding the development of technologies to capture and store the carbon emissions from the fossil-fueled plants that remain. They have even invested heavily in their own portfolios of renewable energy projects.

Despite the tremendous strides countries have made in reducing carbon emissions, the climate has still changed substantially. Again, solar energy offers hope for countries seeking to adapt. To ease water scarcity, countries have turned to cheap solar PV to run desalination plants that transform saltwater into freshwater. Concentrated solar power plants have also been repurposed in the developing world to power refrigeration, preserving badly needed food supplies and blunting famine.

The sobering scientific consensus predicts that the climate will continue to change for the foreseeable future. To stabilize it, governments are in final negotiations before unveiling a massive effort to suck carbon dioxide out of the atmosphere. Some of the countries hardest hit by climate change are clamoring for alternative approaches, like seeding the world’s clouds to reflect more sunlight. Fortunately, governments can afford to deliberate carefully over whether and how to engineer the climate. Sharply reducing global carbon emissions from energy bought them time to do so.

Few would dispute that solar energy has emerged as one of the most important technologies—if not the most important one—of the twenty-first century. It may not have ensured victory over global challenges like climate change. But it has given the world a fighting chance.

Copyright © 2018 by Varun Sivaram. Courtesy of MIT Press.