Will Exponential Growth Get Us to Our Solar Shangri-La?

There’s so much bad news these days that it can be hard to focus on the good stuff. The global trend toward clean energy is, however, one recent trend worth celebrating. So, being a bit of an energy nerd, I thought I’d delve into some of the details.

How’s Kurzweil’s Solar Prediction Faring?

Back in 2011, I read an article claiming that futurist, author and inventor Ray Kurzweil had predicted that solar power would be able to satisfy the entire world’s energy needs in 16 years (that is, by 2027) due to exponential growth in its usage. At the time, I was skeptical but interested. Kurzweil is well-known for his predictions of various future events based on the idea that some trends grow exponentially.

So, here it is 2022, just 5 years shy of the time when the world is supposed to be fully solar.” How are we doing? Well, that depends on your perspective.

In many respects, Kurzweil has proven to be correct. The growth in the amount of solar energy produced in the world has, in fact, been growing exponentially since the year 2000. By my reckoning, the number of terawatts produced by solar power has doubled every 2.375 years. Whereas solar produced just 1.08 terawatt hours (or TWh) of electricity in the year 2000, it produced 1,032.5 terawatt hours in 2021. That’s a remarkable run!

But even if it continues to double every two years over the next five years, solar will still produce roughly 8,000 TWh of power in 2027. Not bad. In fact, it’d be about a quarter of all the power humanity generated in 2021 (28,214.07 TWh). Still, we will not be powering the whole planet with solar by then.

How about if we add wind energy to the mix? Based on my own back-of-the-proverbial-envelope projections, the combination of solar and wind energy has been doubling every 3.5 years or so since 2000. Together, solar and wind produced 2,894.44 TWh in 2021. If that number doubles over the next four years (let’s say), it’ll represent 5,788.88 or so TWh in 2025. Again, pretty great, but by no means powering the whole world.

The Global Growth of Solar and Wind Energy, 2000 to 2021

Created using data from Electricity production by source, World

If solar/wind were to continue to double every four years, however, then it would represent 23,155.52 TWh in 2033 and 46,311.04 TWh in 2037, which is far more energy than humanity produced in 2021. So, Kurzweil’s forecast may well come true, though a few years later than predicted.

Even if it does, however, it won’t be all solar and wind. Hydropower, for example, won’t be going away. Nor will all the nuclear plants be shuttered. But it’s quite possible that between 2033 and 2038 the vast majority of sources of electricity will be completely renewable.

The Dad-gummed S-Curve

The problem, of course, is that sooner or later, solar and wind will hit the so-called S-curve. As the World Resources Institute notes, “Historically, technologies that are growing exponentially have a ‘top speed’ for growth — a maximum growth rate that is achieved, that lasts awhile and then slows down as it approaches 100% adoption. This pattern is known as an S-curve.”

S-curves are probably inevitable for these two forms of renewable energy. After all, it’s one thing to grow from 2 TWh to 4 in a couple of years. It’s quite another to grow from 20,000 TWh to 40,000 TWh in just two years. You’re essentially taking much of the previously installed solar power over a period of many years and then doubling it in just two!

Below is an example of a possible S-curve related to renewables, as shown in “Explaining the Exponential Growth of Renewable Energy.”

From World Resources Institute

When Will the S-Curve Flatten Out?

Nobody quite knows when the S-curve will flatten, slowing the growth of solar/wind power. There are too many variables that remain uncertain. But I think the most important variable is energy storage. If humanity can solve energy storage pretty quickly, then the S-curve will not flatten out for some time. If we can’t solve it, though, then it’ll flatten faster because the all-too-variable renewables will need to be use used in tandem with more reliable sources such as fossil fuels and nuclear.

Lightning in a Bottle

So, will today’s scientists and engineers be able to develop and implement enough robust, cheap and plentiful energy storage to allow renewables to meet their potential? After all, if we could efficiently store energy from the sun and wind so that is available when the wind’s not blowing nor the sun shining, then renewable will be reliable enough to power nearly everything.

[Note: Some experts believe that more infrastructure can serve essentially the same purpose as energy storage: that is, if you have enough renewables plugged into an expanded grid, then some energy source will always be available. For example, the wind will always be blowing somewhere. Of course, this assumes nations will invest in such infrastructure and NIMBY types allow it to be built.)

So far, we haven’t come close to perfecting energy storage, but there has been considerable progress. Since 2019, there have been a rash of articles on how the combination of solar-plus-batteries has become the least expensive way of generating electricity. Science magazine reported that “Solar plus batteries is now cheaper than fossil power.” Forbes reported “New Solar + Battery Price Crushes Fossil Fuels, Buries Nuclear.”

But, as welcome as such headlines were, the stories themselves came with a catch. That is, the lithium-ion batteries in these projects can’t hold a charge for very long and the batteries themselves wear out. In fact, the batteries cited in the Forbes article could only provide electricity for four hours past the time when the sun stops shining. That’s clearly not long enough to make this model capable of getting us to 100% renewable energy.

Nonetheless, we are about to see a ton more of these solar-or-wind-plus-lithium-ion-battery power plants (aka, hybrid projects) come online over the next few years. By the end of 2020, there were 73 solar and 16 wind projects that, altogether, provided 2.5 gigawatts of power generation and .45 gigawatts of storage, Bigthink.com reports.

By the end 2021, about 223 gigawatts of proposed hybrid solar plants were in the works, along with 19 gigawatts of hybrid wind. That’s some pretty Kurzweilian growth there.

Salt, Gravity, Hydrogen and Other Storage Hopefuls

Lithium-ion batteries are the state-of-the-art right now, but plenty of other energy storage tech is in the wings. There is a ton of innovation in this area right now, with news stories popping up every day. Yesterday, for example, it was Scientific American reporting on molten salt batteries.

Researchers at Pacific Northwest National Laboratory (PNNL), a Department of Energy national laboratory in Richland, Wash., are developing a battery that might solve this [long-term storage] problem. In a recent paper published in Cell Reports Physical Science, they demonstrated how freezing and thawing a molten salt solution creates a rechargeable battery that can store energy cheaply and efficiently for weeks or months at a time. Such a capability is crucial to shifting the U.S. grid away from fossil fuels that release greenhouse gases and toward renewable energy.

Then there are ideas such as using gravity to store energy, which is pretty much what hydropower already does. Now, however, they’re trying to make gravity work without water and favorable local geologies. For example, there’s the company Energy Vault, which has been celebrated in the media but is now being criticized as an unworkable idea by some analysts. It’s hard to know if anything will come of these gravity schemes.

Perhaps more promising is green hydrogen–that is, hydrogen fuel produced with renewables. The problem with using hydrogen for energy storage is that it’s not very efficient to turn renewable energy into hydrogen and then use hydrogen to power something else. S&P Global Market Intelligence reports:

The technology to convert power to hydrogen and back to power has a round-trip efficiency of 18%-46%, according to data that Flora presented from the Massachusetts Institute of Technology and scientific journal Nature Energy. In comparison, two mature long-duration technologies, pumped-storage hydropower and compressed air energy storage, boast round-trip efficiencies of 70%-85% and 42%-67%, respectively. Flow batteries, a rechargeable fuel cell technology that is less mature, have a round-trip efficiency of 60%-80%.

On the other hand, I’ve also read that engineers are working at developing processes with a much better conversion efficiency for hydrogen. Even if hydrogen does not turn out to be the most efficient way of storing energy, it could still win the energy storage game if the world produces so much cheap renewable power that a substantial level of inefficiency become acceptable.

Then there’s the really high-tech stuff that is not ready for primetime but may utterly change things when it is. For example, Swedish scientists have reportedly created “an energy system that makes it possible to capture and store solar energy for up to 18 years, releasing it as heat when needed.”

This kind of tech sounds almost magical. “This is a radically new way of generating electricity from solar energy. It means that we can use solar energy to produce electricity regardless of weather, time of day, season, or geographical location,” said research leader Kasper Moth-Poulsen, Professor at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology in Gothenberg.

Now, If We Can Just Reinvent Ourselves

A world in which renewable energy quickly becomes our primary source of power feels inevitable at this stage…unless we screw it up via the worst impulses of our hominid natures. We’ll need, for example, to avoid destroying our infrastructures (not to mention ourselves) via nuclear war while electing responsible politicians who are not beholden to the fossil fuel lobbies and who are better at bringing people together than driving them apart. The world’s richer states will also need to help the poorer ones make the transition to green energies as quickly as possible. And, of course, the scientists and engineers will need to keep doing what they’ve done so well so far: reinventing the way humanity generates its energy.

In short, we’ve solved most of the engineering problems associated with clean energy, and we’re quickly making headway in the one area not yet solved: the storage and stable dissemination of renewable power. We can make it to a green energy global economy if we can just figure out how to listen a little more closely to the better angels of our nature.

Featured image from Lunkwill / derivative work: McSush - Exponential.png

Scenarios for a Pesky and Unpredictable Energy Future

Writing scenarios about energy is about as hip as writing science fiction about time travel or Moon colonies. Energy scenarios are, after all,  the original business scenarios. They are the vanilla of ice creams, the beige of home decorating, the Honda Accord of automobiles.

Scenarios actually began, for the most part, in the energy industry because, in a crazy and shifting world, that industry has always needed to take a long-term view and make long-term investments. That’s why so many people in that industry give off a vibe that is weirdly geeky as well as stodgy and superior. It must be the cross-breeding of engineers and geologists, gutsy wildcatters, fat-cat corporate diplomats, egg-headed forecasters and corrupt marketers.

Perhaps I picked up the energy bug from the study of scenarios in general and some exposure to energy companies. At any rate, I have been thinking and reading about such scenarios for years, and today they are inextricably linked to climate change. So, here are some my recent thoughts all nicely wrapped up in four scenarios.

Year 2032 Climate Change Scenarios

Scenario One: So Far, So Good

Assumptions: lots of green energy as well as geoengineering

By 2032, intelligent geoengineering is no longer controversial. In truth, rightly or wrongly, it has gotten some of the credit for keeping the world cooler than some had predicted it would be.

Some of the credit has gone to the United Nations, which formed the first coalitions of countries that negotiated a sulfate aerosol program that started off very modestly and then grew moderately more ambitious as various nations became comfortable with the technologies.

“We had to find a global approach to geoengineering,” said the Secretary-General of the United Nations. “Unilateral approaches could have caused international conflicts and dangerous unilateral actions.”

Another form of geoengineering, direct carbon capture, has been driven not by the UN but by a large group of nonprofits allied with private investors. After a number of major technological breakthroughs, experts now project that that within 20 years, they will be able to absorb over 30% of the carbon that has been dumped into the atmosphere over the last 100 years.

Then there are the global reforesting efforts, which are sometimes viewed as a “natural” type of geoengineering. There are multiple companies, some of them non-profits, using large squads of drones to conduct fast and effective reforesting.

The trend emerged in 2022 when AirSeed Technologies started using artificial intelligence to find areas in need of trees and fired seed pods from the sky with drones. Even at the time, the drones were reportedly able to plant over 40,000 seed pods per day, far faster and cheaper than via other methods of reforesting. Today, the number has moved past a half million per day.

An ambitious project has emerged as the reforestation companies have started to run out of promising acreage to plant. The new plan is to partner with new desalination enterprises in northern Africa in order to reforest swaths of the Sahara. This is an extension of project begun in 2007 when the African Union decided to build a “Great Green Wall” in hopes of restoring 100 million hectares of land between Senegal in the west and Djibouti in the east. The idea was to create a 15-kilometer-wide and 8,000-kilometer-long mosaic of trees, vegetation, grasslands and plants.

In every case of geoengineering, critics has emerged to warn of dire consequences. The sulfate aerosol program, they warn, may yet have an unpredictable impact since no one can accurately model climate patterns. The carbon capture programs are still unproven, and the reforestation efforts could do more harm that could.

One climatologist states, “If reforestation results in more vast, uncontrolled forest fires, as seems likely, then the process will only serve to add carbon to the air as oppose to remove it, making global warming worse.”

So far, however, these controlled geoengineering initiatives along with the fast spread of green energy sources seems to be working on level.

“So far, so good,” says the the UN Secretary-General. “Yes, some of these initiatives may not pan out. Yes, there are some potential dangers, but it’s best if we engage in these programs in controlled, internationally ordered way when possible.”

To which one critic has said, “Oh, sure, making huge mistakes via unwieldy global bureaucracies is always better. Sure it is.”

Scenario Two: Exponential Green

Assumptions: lots of green energy and little geoengineering

By the year 2020, solar photovoltaics were down to just 5.7 cents per kWh and were seen as less costly than fossil fuels. And, by 2025, the energy storage problem was well on its way to being solved via a combination of new types of batteries, efficiently converted hydrogen, and fuel cells. Investing in other fuel sources started to look like a bad investment, which meant the lower costs came even more quickly thanks to new investments.

But today, in the year 2032, it’s not all about the photovoltaics. Wind energy has also become very inexpensive, and smaller, more modular nuclear plants have made nuclear energy more price competitive. In addition, several small and still experimental nuclear fusion plants have come online.

Most new homes in the U.S. are sold with solar panels and a collection of fuel cells for storing any energy that doesn’t go directly to the electric grid. In addition, most windows are installed with clear carbon nanotube films that can reflect and collect solar energy, depending on the needs of the home.  There’s also a big business in retrofitting older homes.

This means that a growing number of energy consumers have become energy producers or energy neutral, a situation that has continued to annoy energy utilities, especially after several decades of slowing energy usage among home owners in the U.S.

There have also been advances in wireless energy delivery. The most prevalent technologies are based on lasers and magnetically coupled resonance, allowing a wide range of wireless devices to run in households without the need for wires and plugs. But the largest benefits stem from applications that allow neighborhood homes to share solar energy via ad hoc, computer-controlled and wireless grids.

Renewable energy is now estimated to make up 65% of all energy generated in the world. “We expect to the U.S. to hit 95% renewable energy by 2040,” said one utilities CEO. “It represents an amazing achievement. While humanity hasn’t exactly ‘solved’ its energy problems, it feels like we’re on the road to a sustainable future. As an industry, we’re now looking at other markets where we can be equally successful, especially the transfer of high-bandwidth information via utility infrastructures.”

The world hasn’t solved global warming but most experts are optimistic that humanity will be able to cope without the necessity of risky geoengineering projects.

  Scenario Three: Desperate Times

Assumptions: little green energy and lots of geoengineering

Global warming has hit humanity harder than most of the experts predicted. Back in 2022, Nature reported, “The negative impacts of climate change are mounting much faster than scientists predicted less than a decade ago.” It drew this conclusion from Climate Change 2022: ImpactsAdaptation and Vulnerability, a dire but well documented report from the United Nations climate panel.

What occurred in India and Pakistan shortly thereafter only underscored the point. In May 2022, nearly an eighth of the people on the planet found themselves struggling to endure a relentless heat wave. India had just gone through the hottest April in 122 years, which followed the hottest March on record. Pakistan didn’t get off much easier, encountering its hottest April in 61 years. In Jacobabad, Pakistan, temperatures rose above 120 degrees Fahrenheit.

During the heat wave, there was so much demand on the electrical grid that there were power outages for two-thirds of Indian households. Meanwhile in Pakistan, outages were cutting off power when people needed cooling the most, and many families lost running water without electricity.

This was just the beginning. By the mid-2020s, India and Pakistan were regularly besieged by murderous heats waves and droughts. That’s when the two nations, which had long been enemies, joined forces to implement the most ambitious and controversial geoengineering project in human history.

Starting in 2026, they began using high altitude jets so spread sulfate aerosols into the stratosphere with the goal of reflecting away sunlight. Of course, this resulted in a planetary effect that was greeted by outrage in some nations, gratitude in others. Russia almost immediately engaged in nuclear saber rattling, with its president warning, “This is an attack on Russia itself, threatening to make our winters longer, our growing seasons shorter and our storms more destructive. We will not stand idly by as rogue nations assault our food supplies and starve our citizens.”

Meanwhile, India and Pakistan as well as many other nations argued that climate change was the result of trends brought about by Western nations that had no right to inflict existential harm on their countries.

In the U.S., many took the side of India and Pakistan. One Kansas farmer stated, “We’re just glad somebody’s trying something. The droughts have been brutal the last few years, and the cost of irrigation is through the roof. It’s not just us farmers, either. It drives up the cost of food for everyone. Throwing some dust high up in the sky to cool things off a little seems like the commonsense thing to do to me.”

Not everyone agreed. Some climatologists warned that India and Pakistan were not being patient enough and might well overshoot the mark, wreaking even greater havoc on the global environment. “This could end in the kind of wild swings in global temperatures that do far more harm than good,” one warned.

Scenario Four: Hot, Hotter, Hottest

Assumptions: Little green energy and little geoengineering

In the year 2032, green energy has hit the flatter part of S-curve in a major way. The energy storage technologies never quite worked out, so countries have stuck with tried-and-true natural gas even while slowly building nuclear plans hindered by cost overruns. Engineers have done a pretty good job of making automobiles more fuel efficient, not just through better batteries but the more efficient engineering of all the other components, especially the not-yet-dead combustion engine. Most cars, after all, still run at least partly on petroleum.

Fully 55% of all energy production is still based on fossil fuels (only about 5 percentage points of improvement from 2021). But with China and India and growing parts of the African continent still ramping up their economies and energy usage, there’s even more trepidation about global warming. The scientific news has dismal in the shadow of massive and deadly heatwaves, droughts, forest and bush fires, super storms and ever more cases of daytime flooding in coastal cities. Many have given up hope, saying we’re already past a point of no return for high rates of global warming.

This problem has set the stage for a carbon tax that is expected to be implemented by all G25 countries in 2033 (though some U.S. politicians are still promising to withdraw from the pact if elected) . The funds will be mostly allocated to three areas: 1) increasing the reliability of renewable technologies to the point where natural-gas-using peaker plants are no longer needed , 2) greater energy conservation regulations in all forms of engineering, and 3) smaller, cheaper and safer nuclear plants.

“Look,” says one energy guru, “we’ve made progress over the last 20 years in terms of bringing down the costs of renewables, but they haven’t grown at the exponential rate some predicted. Still, global warming has finally gotten bad enough – and the technology good enough – for us to make a global push. We predict that if the political coalition holds, then by 2050 we can get things down to just 35% fossil fuels and the rest nuclear and renewables. Is it as good as we hoped? No. Are we going to suffer from even worse global warming? Yes. But half a loaf is better than none.”

Given the slow pace of progress, more and more nations are developing geoengineering strategies, but little has been implemented. Large-scale geoengineering initiatives remain controversial and are still being debated in the United Nations and elsewhere.

Concluding Comments

Which of these scenarios is most likely? I don’t know. The one I’d like to see most is “Exponential Green” but it’s hard to say how quickly green energy will grow and, even assuming exponential growth for now, when the trend will slow down and hit the S-curve.

We may need to add geoengineering to the mix in order to avoid disaster, but geoengineering comes with its own risks. Thing can and often do go wrong. Engineering solutions can result in unforeseen problems. If we do need to engage in geoengineering at a large scale, I hope it’ll look more like “So Far, So Good” rather than “Desperate Times.”

The best we can do, I think, is help bring the most positive of the scenarios to fruition. Even if they don’t work out, we will have spent more days in hope than despair. There’s something to be said for active optimism.

Featured image from 林 慕尧 / Chris Lim from East Coast (东海岸), Singapore (新加坡) - Windmills in China?{D70 series}