You have 100 'energy slaves'

They pump your water, toast your bread, and move your car: Understanding the 'embedded energy' that powers our modern lives.

I haven’t been posting much in the last month or so because I am in the home stretch of finishing a textbook on climate risk¹. I plan to post chapters in the spring, but I thought I would post this section on embedded energy now. Read it and appreciate how much our modern energy system does for us.

What is embedded energy?

Consider an iPhone. Its constituents were once sand and ore, transformed through energy-intensive manufacturing into glass, metal, silicon, and countless other advanced materials.

The total energy required to create an iPhone is what we call its “embedded energy.” This includes the energy consumed in extracting raw materials, manufacturing components, transporting goods, maintaining infrastructure, and eventually disposing of or recycling products at the end of their useful life. It includes the energy consumed in writing the software and running the cloud services that the phone relies on.

Embedded energy is everywhere. A steel beam embodies the energy used to mine iron ore, smelt it into steel, and transport it to a construction site. A hospital building represents not just the energy used in construction, but the ongoing energy required to heat, cool, light, and operate it.

Every good (road, building, vehicle) or service (a university lecture, an hour of tax preparation) requires energy without which that good or service would not exist.

Example: a Big Mac

Consider the humble Big Mac. The bread requires energy to grow the wheat, mill it into flour, bake it, store it, and ship it across supply chains. The hamburger patty requires energy to grow the grain that feeds cattle, as well as the energy to slaughter, process, refrigerate, and cook it. Even small ingredients like pickles and onions contribute.

When everything is added up, a single Big Mac embodies around 10 megajoules (MJ) of energy. To provide context for this number, know that an adult doing sustained, hard physical work might produce about 100 joules per second of useful power.

How big is 100 J/s? A joule of energy is about the same energy it takes to lift an apple from the floor to a nearby table. Thus, 100 joules per second is the same as lifting 100 apples (about 20 lb) from the floor to a table every second. As I said, that’s hard physical labor.

It would therefore take a human roughly 10⁵ seconds² ≈ 24 hours of strenuous labor to generate 10 MJ of energy. Since you can’t work hard for 24 hours straight, it would be more realistic to think of it as three 8-hour days of sustained labor.

I don’t know about you, but if I had to work three eight-hour days of hard labor to make a Big Mac, I would never eat one.

Luckily for us, most of the required “labor” is provided by our modern energy system, powered today mainly by fossil fuels. Without this, what feels routine to us today (i.e., ordering a Big Mac) would demand heroic effort.

Before fossil fuels, this level of energy access was reserved for kings, nobles, or slaveholders—those who could literally have hundreds of people working to produce their goods and services.

Ordinary people simply did not have access to enough energy—human or animal—to ever enjoy the equivalent of a Big Mac. Our “normal” lifestyle today would look like unimaginable luxury to anyone who lived before the industrial age.

Energy is basically free

It is a common refrain today to lament the “high cost of energy.” For example, drivers might complain about paying $2.50/gal for gasoline (in Nov. 2025). While that price can feel burdensome, it is actually an unbelievable bargain.

The amount of energy concentrated into that gallon of gasoline is truly astonishing: 124 MJ. To put that in a human context, it would take a human (producing 100 J/s) 344 hours, more than 14 straight days, of non-stop physical labor to generate that much energy.

In other words, you can replace 14 days of hard, high-effort human work for $2.50³. This is what makes our modern world possible, and its value becomes clear when applied to everyday tasks.

Imagine you want to take five of your friends, along with their luggage, on a one-mile trip. In a typical car, this would consume about half a cup of gasoline (4 fluid ounces). At $2.50 per gallon, the fuel for this trip costs about 8 cents. For this small cost, you have effortlessly transported over 1,000 pounds of people and cargo for a full mile in just a minute or two.

Now consider accomplishing this feat with human muscle. It would require a team of people pushing and pulling a heavy cart, a task that would be an arduous, sweat-soaked nightmare. From this perspective, gasoline is not just cheap, it’s basically free. Even if the price were to increase tenfold to $25 per gallon, that one-mile trip would cost only 80 cents—still an exceptional deal for the sheer amount of work performed.

The contrast between human labor and fossil fuel power becomes even more stark when considering larger projects. Imagine you decide to install a moderately sized swimming pool in your backyard, measuring 15 feet wide, 30 feet long, and an average of 5 feet deep. To create this space, you would need to excavate and move approximately 85 cubic yards of earth, which weighs over 100 tons.

If you hired a team of four strong workers equipped with shovels and wheelbarrows, they would face a monumental task. Assuming each person could dig and move about one cubic yard per day—a generous estimate for such demanding labor—the project would take the entire team over 20 full workdays, representing a combined total of more than 640 hours of back-breaking manual labor.

Now, let’s accomplish the same task with our modern energy system. A single person operating an excavator can complete the entire job in one day. The excavator might consume 10-20 gallons for the entire project. At a cost of, say, $3.00 per gallon for diesel, the total energy expense to excavate the 100-ton hole would be $30-$60. When compared to the thousands of dollars in wages and weeks of grueling effort required for human labor, the fuel cost is practically a rounding error.

This demonstrates a profound reality of our energy economy: fossil fuels represent a vast, condensed subsidy of labor, allowing us to achieve feats of engineering and convenience that would have been inconceivable for all but the most powerful in past ages.

Watch this video and consider how many people you would need if you didn’t have an excavator running on diesel.

Average power

Let’s quantify the labor that our modern energy system does for us. When we talk about energy in everyday life, we often focus on single events: how much energy is in a hamburger or how much an airline flight uses. But to understand the energy demands of a lifestyle, it is more useful to think about average power.

Power measures how fast energy is being used or supplied. The unit of power is the watt, abbreviated W, which is one joule per second. So if you know how much energy is consumed over a period of time, you can estimate power = energy ÷ time.

For example, suppose someone eats one hamburger every day of the year, and each hamburger requires 10 MJ of energy. The total energy required to create these 365 hamburgers is:

Energy = 365 hamburgers × 10 MJ per hamburger = 3,650 MJ.

To turn that into average power, we divide energy by the number of seconds in a year. There are 31.6 million seconds in a year (365 days × 24 hours × 3600 seconds):

Average power = 3,650 MJ ÷ 31.6 million seconds ≈ 120 W

This means that eating one hamburger a day corresponds to a continuous power demand of about 120 W⁴.

We can then add this to all other things you do. For example, let’s assume you also take a single round-trip international flight each year. This trip will consume around 700 liters of jet fuel per passenger, corresponding to 30 gigajoules (GJ) of energy, including the energy for fuel production, airport operations. If someone takes one such trip each year, the average power is calculated by dividing 30 GJ by the 31.6 million seconds in a year. This gives an average of about 1,000 W = 1 kilowatt (kW).

Thus, if you eat one hamburger each day and take one international trip each year, your lifestyle consumes 1,120 W of power. Without our modern energy system, this would require eleven people working all of the time. We can think of the these hypothetical people as “energy slaves”, a term coined by Buckminster Fuller.

A house also has a large amount of embedded energy, because building it requires producing materials like concrete, steel, lumber, insulation, and glass, as well as powering construction equipment. Suppose the total embedded energy of a home is 5,000 GJ (equal to 5,000x10⁹ J) and it has a 50-year lifetime.

To find the average power, spread the energy across the roughly 1.58x10⁹ seconds in 50 years:

Average power = 5,000x10⁹ J ÷ 1.58x10⁹ s ≈ 3,300 W = 3.3 kW

If three people live in the house, then this corresponds to 1.1 kW of power per person for housing. Adding that to your one-hamburger-per-day-and-one-international-flight-per-year lifestyle gives you a total average power of 2.4 kW. Your life now requires 24 energy slaves working for you, every minute of every day of every week of every year.

Adding the power from everything the average American consumes yields an average power consumption of 10 kilowatts per person. If you divide this average by the output of a human laborer (100 W), you find that each American relies on the equivalent of around 100 energy slaves.

They pump our water, move our goods, light our homes, produce Big Macs, and move data through the internet. We rarely think about them, but they are always there, embodied in everything around us.

To better understand how puny humans are, watch a professional cyclist with legs like Christmas hams toast bread with just human power. If you relied on your muscles, you’d never toast bread.

The disposable economy

Our modern economy relies heavily on disposability. If your toaster breaks, the cheapest option is to buy a new one rather than repair what already exists. Manufacturers reinforce this by designing products that are difficult to fix. Components are sealed away, parts are proprietary, and software locks limit access. Even if repair is possible, replacement is often cheaper and more convenient.

This throwaway system keeps economic activity high but wastes energy. Making a new product always consumes far more energy than repairing one that already exists. Your toaster might embody 100 MJ of energy from producing metal parts, wiring, and heating elements. Repairing a broken lever or replacing a heating coil might require only a few MJ of new materials and manufacturing effort.

Throwing out the broken toaster and buying a new one wastes nearly all of the energy already invested in the original product and leaves behind mountains of waste. Repairing, when possible, preserves that embedded energy and avoids restarting the entire production chain.

In this way, better design can reduce the amount of energy our economy needs. Products built to last reduce the demand for mining raw materials, running factories, and shipping goods around the world. If devices are designed so they can be repaired, we avoid the large energy cost of making replacements.

Cities planned to reduce driving not only cut fuel use but also shrink the need for roads and other infrastructure that supports sprawl, thereby also lowering embedded energy. The energy saved can instead be used to improve people’s lives.

This emphasizes that our 10-kW lifestyle is, to some extent at least, a social, economic, and political choice. A system built on disposability makes businesses profitable in the short term, but it offloads waste and climate hazards onto the future and increases our energy demand.

The global context of the 10 kilowatt lifestyle

The average resident of the United States benefits from an energy-rich standard of living that requires 100 energy slaves equal to 10 kilowatts of continuous power per person.

Without cheap energy, very few of us could afford to live the lifestyle we do.

This is why I believe we should tip our caps to what fossil fuels have enabled. They are a remarkable energy source that built the modern world, lifted billions from poverty, and provided the foundation for nearly every comfort and technology we now take for granted.

But the energy conversation is not about the past but about the future. Acknowledging the pivotal role of fossil fuels in the past is not an argument for their indefinite future use. Rather, it challenges us to preserve the incredible benefits we’ve received from fossil fuels while eliminating the side effects that come with them: climate change, air pollution, and geopolitical instability.

The challenge is starker when you consider that the global average rate of energy consumption is around 2 kW per person. Many countries in Africa and South Asia rely on less than 1 kW. These differences shape quality of life, affecting everything from health care and transportation to education and economic opportunity.

These people deserve access to more energy to spur development. But if the world follows the same fossil-fuel path that powered industrial growth in wealthy nations, global emissions will soar and the climate crisis will deepen.

The solution is not to limit access to energy, but to change how energy is produced and used. We need transportation and industrial systems that do not depend on burning fossil fuels, buildings designed to use less energy, and a massive expansion of renewable and low-carbon power. With those changes, the world can raise living standards while preserving our climate and air quality.

We have the technology to largely do that already but we’re not because of the enormous power of fossil fuels. The clean-energy transition is not a scientific or technical problem, it’s a political one.

This is a draft of a section of my climate risk textbook (slightly edited & reformatted to make it appropriate for Substack). I’d very much like to identify errors now, so if you see any, please let me know in the comments.

Other stuff to check out

• Economist Blair Fix has done a deep dive into some statistical oddities of Roger Pielke Jr.’s contention that “[climate] losses per disaster are down by about 80% since 1980, as a proportion of GDP.” This claim is good news if true, but Fix shows that the analysis uses some dodgy statistics. See his analysis here.

• After Hurricane Melissa hit Jamaica, there were renewed calls for adding a “Category 6” to the hurricane intensity scale (the Saffir-Simpson scale). I wrote about that suggestion a while back, so check it out.

• With hurricane season about to end, no hurricanes hit the U.S. this year. Nevertheless, it was a worrying year. Make no mistake: due to climate change today’s hurricanes are more destructive than they were in the past.

I’d be grateful if you could hit the like button ❤️ below! It helps more people discover these ideas and lets me know what’s connecting with readers.

1. Also, Zeke told me that people were sick of me writing about the DOE Climate Working Group report.

2. 10,000,000 J ÷ 100 J/second = 100,000 seconds

3. I’m ignoring the thermodynamic constraints of converting heat to work, but even taking that into account, the essential message remains the same.

4. You would have gotten the same answer if you calculated the average power of eating one hamburger each day for a week or one hamburger each day for a month. The key is to know how many you eat over a specified time period.