Our Renewable Future


To begin to grasp how our energy useage will shift during the renewable energy transition, it is essential to first understand how we currently use energy throughout society. And in order to do that, it’s helpful to sort this usage by sector.

The International Energy Agency estimates that we consumed the equivalent of 13.54 billion metric tons of oil (or 157,483 terawatt-hours) globally in 2013, broken down into the somewhat opaque categories of Industry, Transport, Other, and Non-energy Use (“Other” essentially refers to buildings.) It’s interesting to note that the amount of energy lost—in transmission or conversion—or used by the energy industry itself is a whopping 31%.


World primary energy consumption in 2013, by sector, according to the International Energy Agency. Industry excludes energy conversion. Losses through the process of conversion and transmission (particularly in the form of electricity), along with the energy required by energy producers themselves, represents the single largest area of consumption. Source: International Energy Agency.

But even this classification of energy consumption doesn’t help us get a clear idea of how we really use all that energy or how deeply—and often invisibly—energy is embedded in our daily lives.

So, in this section of the website we’ll explore a few sectors of the American economy—transportation, food, manufacturing, buildings, water, and communications—to get a better sense of the energy reality of today, so that we can build a more sustainable and just energy future.


We could not cover every possible sector (we left out, for example, education, entertainment, finance, and the military), but in many cases energy uses in these other sectors are largely accounted for in the sectors we have covered. For example, these sectors all use energy to heat and light buildings and for communications, and all depend upon energy expended in transport and in manufacturing goods of various kinds.

This raises the issue of linkages. All of society’s sectors are tightly linked. For example, without food for workers in the communications, transport, and construction industries, those industries couldn’t function. Similarly, energy-using communications technologies are essential to the workings of the transport, food, construction, and manufacturing sectors. And communications systems can’t work without the transportation of spare parts and new components. And yet again, transportation is necessary for moving other kinds of manufactured products, as well as building materials and food.

While we’re at it, where would we warehouse food or retail products, including communications devices, without functioning buildings? How could we maintain our food system without the ability to manufacture farm machinery, or our communications systems if we couldn’t manufacture replacements for our hand-held devices and all the behind-the scenes infrastructure that enables them to work? And how long would our transportation system function without newly manufactured vehicles, tires, and other spare parts?

In sum, the economy’s sectors are thoroughly and intricately interdependent; modern societies are systems in which energy knits everything together, and makes possible everything we do.


Tractor being assembled in a John Deere factory. Photo credit: 279photo/Shutterstock.com.

Finance also links all of society’s various sectors—though, from an energy usage perspective, banking and finance are already accounted for in the communications and buildings sectors (as noted above). Credit and debt enable manufacturing, car purchases, building construction, and farming. While the direct energy footprint of finance and banking is not proportionally large, the energy used for this purpose plays an essential role in the functioning of our entire society.

The following sections explore the energy use of some of these sectors in depth. Each sector also includes a short exploration of the fossil-fueled foundations and energy interdependencies of our current energy system by examining some examples from everyday life. Seeing how thoroughly, and how subtly, fossil energy consumption is implicit in in our current world can then help us begin to imagine life without fossil fuels.

Getting a Sense of Scale

BTUs, quads, watts, joules, barrels of oil equivalent, gigawatt-hours… It’s easy to get confused by all the different units of measurement used to calculate energy volume, power, or intensity. And when numbers like 157,483 terawatt-hours are tossed around, it can be very hard to have a true sense of scale. So here’s a (hopefully) helpful visualization.


Transportation systems move people. They also move freight—stuff—including raw materials and manufactured goods. People move themselves around mostly by means of cars, buses, planes, trains, and bicycles, while we mostly move our stuff with trucks, trains, ships, and planes.

By weight, we move far more stuff than people: the combined weight of all the people in the U.S. is about 24 million tons, while in 2012 we moved nearly 20 billion tons of stuff (roughly 800 times as much). But while people weigh so (relatively) little, over 70% of the total energy consumed by transportation in the U.S. that year went to moving us, not our things, around.

Energy consumed in the transport of people and goods in the U.S. in 2012. Over 70% of total operational energy consumption went to moving people, though the combined weight of all people in the U.S. is a tiny fraction of the weight of stuff moved each year. Source: U.S. Department of Transportation, Bureau of Transportation Statistics.

According to the International Energy Agency, the amount of useful energy that human societies consumed in 2013 totaled 9.3 billion metric tons of oil equivalent (108,159 terawatt-hours). Of that total, 28 percent was used for transportation.

One resource dominates operational energy in the transportation sector: oil, from which we make different types of liquid fuels for our various vehicles. Gasoline fuels the vast majority of passenger cars (of which there are roughly a billion worldwide). Diesel powers trucks, buses, about half of the world’s trains, and some automobiles. Bunker oil fuels large ships, while most commercial aircraft burn aviation-grade kerosene.

New cars unloaded at Sydney harbor. Photo credit: Mark Higgins/Shutterstock.com.

About half of the world’s trains are electric (the proportion is much smaller in the U.S.), and electricity also powers subways, streetcars, and a growing number of electric buses, cars, and bicycles. But even so, nearly 93% of transportation is fueled by oil.

While most of the energy consumed by transportation is in the operation of vehicles, a great deal of energy—the vast majority of it from fossil fuels—is embodied in the manufacturing and maintenance of vehicles, roads, rails, parking structures, and airports. (This embodied energy is not accounted for in the transportation total above.)

Each typical automobile represents about 48 megawatt-hours (MWh) of embodied energy, or the equivalent of 29.5 barrels of oil. That means manufacturing the nearly 90 million new vehicles produced globally in 2014 required more energy than the amount of total renewable electricity produced in the world that year: 4,300 terawatt-hours (TWh) vs. 3,685 TWh.

Manufacturing all the new cars built in 2014 require more embodied energy that all the renewable electricity produced that year.

Roads also embody large amounts of energy: the energy used in constructing one lane of road one kilometer in length is the equivalent of burning 23,000 gallons of conventional gasoline. Thus the global network of 65 million kilometers of paved roads represents about 1.5 trillion gallons of gasoline in embodied energy.

All this is to say that, even if we were able to substitute vehicles that run on petroleum—planes, trains, automobiles, and ships—with ones that ran on renewable electricity, we’d still have the challenge of substituting all the fossil fuels that go into their manufacture, maintenance, and disposal, along with the infrastructure (the roads, bridges, parking, etc.) that supports them.

Workers and equipment laying asphalt. Photo credit: Stockr/Shutterstock.com

Example: A Hybrid Electric Car

On the whole, passenger vehicles are getting more efficient (though, put in perspective, driving a car remains a woefully energy inefficient mode of transport)—with the average fuel efficiency of a new car sold in the U.S. now at a little over 25 mpg. In comparison, the most popular “green” car on the market—the Toyota Prius—gets double that. It’s a big improvement. But what about the energy needed for everything other than driving the car?

The estimated embodied and operational energy consumed by a 2014 Toyota Prius per mile traveled. The majority of the energy consumed is in operating the vehicle but the manufacturing and disposal of the car, along with the infrastructure (roads, bridges, parking) that supports it, are the most challenging to substitute energy sources. Source: Conventional, hybrid, plug-in hybrid or electric vehicles? State-based comparative carbon and energy footprint analysis in the United States.

Manufacturing a Prius requires sourcing and transporting raw materials, including steel, glass, copper, cast aluminum, lithium, synthetic rubber, plastics, magnesium, and platinum. Electricity was used in some of these sourcing operations, but the overwhelming majority of the energy used was in the form of natural gas, oil, and coal.

The maintenance of the vehicle requires replacement parts, lubricating oil, tires, a repair facility (running largely on electricity), and transport of parts, oil, and tires (more oil). The tires are made of a synthetic rubber derived from oil, about one barrel of which goes into manufacturing each tire.

Although the Prius has an electric motor on board, it cannot be plugged in so as to charge its battery with electricity from an external source—instead, its battery charges from the kinetic energy captured while the vehicle is braking. Its electric function serves merely to increase its fuel efficiency. The car’s operational energy therefore comes entirely from gasoline.

We would not be able to operate the car if it were not for an extensive system of roads and bridges. National, state, and local governments spend enormous sums annually to build and repair these roads, using asphalt, steel, concrete, lumber, and aggregate; the energy fueling this road-building and repair activity is overwhelmingly from oil.

Finally, when the car reaches the end of its useful lifetime, it will require disposal at a facility dedicated to this purpose. Energy (in the forms of electricity and oil) will be expended in transporting the car, demolishing it, and recycling its components.

Compressed, crushed cars. Photo credit: Marso/Shutterstock.com.


There are many different kinds of manufacturing systems, all geared to the production of a bewildering variety of items, from buttons to battleships.

Each of these products starts out as raw materials. Therefore, the manufacturing sector depends on—and could be said to include—mining (for minerals), forestry (for wood), and agriculture (for the production of cotton and other natural fibers).

Open pit copper mine, Serbia. Photo Credit: Bora030/Shutterstock.com.

The U.S. mining industry uses about 366 gigawatt-hours (GWh) per year (32 million tons of oil equivalent)—mostly in the forms of diesel fuel to power excavators, trucks, and other large mobile equipment, and electricity to power conveyor belts and other smaller machines. In the case of manufacturing of plastics, fertilizers, and petrochemicals, the raw materials themselves are made from fossil fuels—primarily natural gas, natural gas liquids, and petroleum condensate.

It’s not just the extraction of the raw materials that comes with a sizable energy cost. Any raw material usually has to be transformed into a more readily usable form (iron ore into steel, bauxite into aluminum, limestone into cement), and these transformation processes often involve high heat—for example, 1,500 degrees Celsius for making cement.

Cement plant in Hong Kong. Photo Credit: cozyta/Shutterstock.com.

Coal and natural gas are typically used for high-heat industrial processes, though electricity is employed in arc furnaces, for aluminum smelting, and in a few other applications.

Electricity accounts for less than one fifth of the final energy consumption of the U.S. manufacturing sector, according to the Energy Information Administration. The vast majority comes from oil, natural gas, coal and related by-products used both for fuel and as feedstock.

Final energy consumption in the U.S. manufacturing sector in 2010, based on self-reporting from industry via the U.S. Energy Information Administration’s Manufacturing Energy Consumption Survey—including both as a fuel source and feedstock. “Other” includes renewable energy produced on site or purchased. It’s so large because, in the paper industry, there is extensive use of the “black liquor” by-product from pulping to generate the energy needed in the plant (and pulping plants are virtually self-sufficient as a result). For the refining and petrochemical industries, all non-energy use (e.g. petrochemical feedstocks) are similarly lumped in the “Other” category. LPG = liquefied petroleum gas. NGL = natural gas liquids. Source: U.S. Energy Information Administration, Manufacturing Energy Consumption Survey.

Once materials have been transformed and molded or fabricated into parts and components (often using electricity), assembly occurs using human labor or electric robots, assisted by electrically powered tools and assembly lines.

Visualization of global shipping traffic in 2012 created by Kiln and the UCL Energy Institute. Full size map at https://www.shipmap.org/.

Of course, at every stage of manufacturing—from mining to final delivery of the finished product—transportation is required, which depends mostly on oil (see Transportation). Most of the products we use on a daily basis—our clothes, toothbrushes, televisions, computers, etc.—are resourced, manufactured, assembled, and packaged thousands of miles away.

Example: A Pair of Jeans

Most American families purchase their clothing items at giant discount stores. The majority of these items are made in other countries, including China, Indonesia, India, or Mexico; in fact, individual items are usually assembled in a number of different countries, depending on labor, specialization, and local resources.

Few people think much about how these clothes were made, by whom, under what conditions, or how much energy use and carbon emissions were entailed. Since their clothes are remarkably inexpensive, many American families replace them on a regular basis. The United States generates 21 billion tons post-consumer waste textiles per year, about 82 pounds per resident. Of that, 85% goes into landfills. And the amount going to landfills is growing much faster than the amount being diverted to donation or recycling.

Textile waste in a landfill in India. Photo still from the film The True Cost.

The lifecycle of a pair of jeans can be said to fall into six phases: cotton production, fabric production, garment manufacturing, transportation & distribution (including retail), consumer use, and disposal. A small percentage of jeans will start the process again through recycling.

In 2009 and 2015, Levi Strauss published the results of lifecycle analysis of the energy and environmental impacts of a pair of 501® Jeans. They found that largest source of energy consumption and climate impact is when the jeans are washed—often in warm or hot water, which is heated directly by natural gas or fossil fuel powered electricity—and likewise dried in machines powered by fossil fuel sourced electricity.

Energy use (in kilowatt-hours) and climate impacts (in kilograms of carbon dioxide equivalent) of a pair of 501® Jeans over its lifetime, according to lifecycle analysis conducted by Levi Strauss. The lifecycle energy consumption is roughly the equivalent of running a modern laptop computer for over 2,000 hours. The climate impact is roughly the same as driving an average car about 80 miles. Source: Levi Strauss.

This energy use can be easily reduced by wearing jeans more often before cleaning, by washing them in cold water, and by hang drying. And the climate impacts can likewise be reduced by using renewable energy sources for electricity.

Much more challenging is reducing fossil fuel inputs during the cotton and fabric production phases. Cotton typically comes from intensively managed farms, like those in China. High yields are achieved through seedling transplanting, plastic mulching, double cropping, plant training, and super-high plant density. However, these techniques are labor-intensive and involve a large input of chemical products like fertilizers (natural gas), pesticides (natural gas and natural gas liquids), and plastic films (natural gas and natural gas liquids).

Crop sprayer spraying young cotton plants in a field in the San Joaquin Valley, California. Photo credit: Balefire/Shutterstock.com.

Additionally, clothes and the raw materials that went into making them had to travel thousands of miles—usually via diesel-powered container ships. Because clothes are relatively small, lightweight items, transportation is responsible for only a minor portion of total energy expended. However, the delivery of these goods cannot easily be accomplished without oil-powered container ships and diesel-burning trucks.


In 2015, 40 percent of U.S. energy was used in residential and commercial buildings (11,430 terawatt-hours). Of this total, residential buildings account for 54 percent and commercial buildings 46 percent.

About half the operational energy in U.S. homes and businesses goes toward heating, ventilation, and cooling (HVAC), which employ natural gas, electricity, and, in some areas, oil. The next biggest energy uses are for lighting, which is nearly all electric, and for heating water, which typically uses natural gas and electricity. Energy use within buildings also includes electronics (electricity), refrigeration (electricity), and cooking.

A breakdown of operational energy use in U.S. buildings, by type. The majority of this usage is in the form of electricity. Source: U.S. Department of Energy, Buildings Energy Data Book.

Building construction also requires significant amounts of energy usage: the total amount of energy embodied in the construction and maintenance phases may account for 20 percent of a building’s lifetime energy use, and even higher in efficient, low-energy buildings.

Energy is used in the manufacturing of components and materials (coal, oil, natural gas, electricity), in the transportation of materials and workers to the construction site (oil), and in the construction process itself (electricity, oil). Steel, concrete, wood, copper, glass, paint, insulation materials, sheetrock, and aluminum all require energy of different kinds and amounts in their manufacture.

View of a construction site in New York City. Photo credit: Victor Maschek/Shutterstock.com.

The buildings sector offers many significant opportunities for improved energy efficiency—both in operations and in construction. Heating and cooling could in most instances be electrified and made more efficient by the use of air-source and ground-source heat pumps, while the need for heating and cooling could be reduced by better design and the use of more insulation. Buildings could also be designed and materials selected to optimally balance embodied energy and operational energy needs (e.g., by designing for passive lighting, heating, and cooling).

Example: A Suburban Home

A suburban American home. Photo credit: rSnapShotPhotos/Shutterstock.com.

The typical suburban American home was constructed sometime during the past 30 years according to building standards that assumed the home’s occupants would have unlimited access to cheap, fossil-fueled energy.

The building uses external energy sources to heat, cool, and move the air it encloses; to light its rooms even during daytime hours on sunny days; and to heat its own water quickly and at any time. The building was designed, in essence, merely to enclose space as cheaply as possible, with all amenities provided by machines consuming energy from external sources, most tracing back to fossil fuels.

Insulation after removal of drywall in a residential home. Photo credit: Jo Ann Snowver/Shutterstock.com.

About the only nod to energy efficiency during the building’s construction phase was the use of R-20 fiberglass insulation in the walls and ceilings. Even in temperate zones, the house may cost hundreds of dollars per month to heat in the winter and cool in the summer. The home is likely heated with natural gas and cooled using electricity.

Daylight enters through windows, but there typically has been no systematic and deliberate effort to maximize the practical use of daylight through southern orientation of the building’s windows, or the installation of skylights or solar tubes. The lighting in the house, at least, is provided by energy-efficient, compact fluorescent bulbs as these have been standard and affordable for years.

The average energy consumption of a single family, detached home in the United States in 2009, by fuel type and end-use. This allocation is based on dividing total consumption figures by the total number of single family, detached homes in the U.S. In actuality, homes don’t use multiple fuel sources for the same end uses (for example, electricity and natural gas for space heating). “Other” includes end uses not shown separately (e.g., cooking appliances, clothes washers, dryers, dishwashers, televisions, computers, small electronic devices, pools, hot tubs, and lighting.) Source: Energy Information Administration, Residential Energy Consumption Survey.

Most homes are constructed with a standard set of materials: plywood and particle board (production of which often contributes to deforestation and results in emissions from particle matter, veneer dryers, and adhesives); PVC (made from natural gas and natural gas liquids); concrete (whose key ingredient, cement, is carbon-intensive and is made using coal); vinyl (made from natural gas or natural gas liquids); steel (coal is used in the early phase of production); copper (oil is used for mining the ore, coal for smelting); and glass (coal or natural gas is used to produce high temperatures). Each construction job generates a heap of unusable scraps that has to be taken to the landfill for disposal.

A residential home under construction. Photo credit: val lawless/Shutterstock.com.

In addition, many conventional building materials now originate in China, where they are manufactured more cheaply. The United States formerly led in the production of all these materials, but for many years now most American building materials companies have sourced their products from overseas—requiring transport over thousands of miles using diesel-powered trains and cargo ships.

Most houses start with a concrete foundation pour. A framework of steel rebar (likely produced in China using coal) is laid, over which the concrete is poured.

Rotary kiln, used in the production of cement. Photo credit: Yuangeng Zhang/Shutterstock.com.

To make cement, limestone and other clay-like materials are heated in a kiln at 1400 degrees C (usually using coal as a heat source) and then ground to form a lumpy, solid substance called clinker, which is then combined with gypsum. Altogether, the cement industry is responsible for five percent of global greenhouse gas emissions, with each ton of cement responsible for about a ton of carbon emissions.

Food System

The United States food system uses about 4,300 terawatt-hours (TWh) annually, which represents about 15 percent of total primary energy consumption (it was estimated to be 14.4% in 2002).
So how, specifically, is energy consumed in the food system?While its slice of the overall energy pie may seem relatively low, the modern American food system is figuratively awash in fossil fuels. On average, roughly 12 calories of (mostly fossil fuel) energy go into producing just one calorie of the food that we consume. The use of fossil fuels in every phase of the food system—from fertilization, treatment, and harvesting to manufacturing, packaging, distribution, and preparation—has utterly transformed what we eat, how we eat, where we eat, and how our food is grown. Arguably, our bodies have gone through as much transformation as a result of the industrialization of agriculture as the food system itself.


A breakdown of energy use in the U.S. food system. Data is based on analysis of 2002 data. Source: Energy Intensity of Agriculture and Food Systems.

Refrigeration—critical to the long-distance supply line of many foods—is one of the biggest users of energy in the food system (approximately 15 percent, if you include refrigerated trucks, household refrigeration, and retail), employing electricity in the great majority of cases.

While agriculture is the basis of the food system, it accounts for only about 13 percent of food system energy. In industrial farming, the single largest energy input is in the form of fertilizer, which relies on a process that transforms fossil fuels (usually natural gas) into ammonia.


Tractor spraying fertilizer on corn crops. Photo credit: Fotokostic/Shutterstock.com.

Farm machines such as tractors, harvesters, and combines burn diesel fuel, while pesticides and herbicides are typically made from petrochemicals.

Processing of food is also highly energy intensive (17 percent of food system energy), with natural gas and electricity being used for cooking, baking, grinding, slicing, blending, and other activities.

Packaging accounts for five percent of food system energy, via the production of plastics (mostly from fossil fuel feedstocks, though some bioplastics are entering the stream) and cardboard. The latter is often recycled, but much end-use packaging is simply discarded to landfills.


Slices of meat in packages on a factory conveyer belt. Photo credit: branislavpudar/Shutterstock.com.

Transport of inputs to farms, and outputs from the farm to table, accounts for about three percent of food system energy; as noted in the transportation sector description, the great majority of energy used for these purposes is in the form of oil.


Embodied and operational energy inputs of food production compared to caloric outputs from food consumption for different types of food in the U.S. food system. Source: United States Department of Agriculture, Energy Use in the U.S. Food System.

Within the overall food system, energy is embodied in farming, transport, and processing machinery, as well as packaging. However, food itself represents embodied energy: As stated earlier, about 12 calories of energy are currently required to produce, process, and deliver each calorie of food (on average) within the U.S. food system. However, some foods are far more energy-intensive than others: whole grains, fruits, and vegetables embody less energy, while meat (especially beef) and highly processed snack foods embody much more.

Example: A Bowl of Cornflakes

Cornflakes are part of many Americans’ breakfast. But how do they get to the table, and what energy is needed to make that happen?

The story of a bowl of cornflakes begins on a farm—say, in Iowa—which grew corn using diesel fuel (derived from oil) to power machinery for plowing, seeding, harvesting, and production. Oil-powered machines were also used for applying nitrogen fertilizer and herbicides, and even earlier for mining, transporting, and processing phosphorus and potassium fertilizers. After harvest, the corn was trucked (using oil) to a grain elevator, where it was dried (natural gas); then it was transported by rail (oil) to Michigan for processing.


A truck loads grain in Rapson, Michigan. Photo credit: John E Heintz, Jr./Shutterstock.com.

After processing, the cornflakes were packaged in a plastic bags (oil) and cardboard boxes. The boxes were made from wood pulp originating in Georgia (oil for harvesting and transport, gas for processing heat), and the graphics on the box were printed (the presses run on electricity) using petroleum-based inks.

The boxes of cornflakes were trucked (oil) to a warehouse (most operations including lighting, cooling, and pallet trucks are electric). From there the cornflakes were trucked (oil) to the store where they were purchased. They were then transported home—most likely by car (more oil).


The energy embodied in the production, manufacturing, packaging, distribution, and consumption of a box of cereal. The lines colored red (oil), blue (natural gas), and electricity (yellow) conceptually illustrate the accumulation of embodied energy and are not correlated to specific values. Source: Post Carbon Institute


In the United States and most of the rest of the industrialized world, energy and water have a symbiotic relationship; it’s sometimes called the “water-energy nexus.” A great deal of energy is expended to extract, move, use, and treat water. And fresh water is a key ingredient in most forms of energy production.

The interrelationship of water and energy in the United States. gphd = gallons per household per day. Source: U.S. Department of Energy, Energy Demands On Water Resources: Report to Congress On The Interdependency Of Energy and Water.

In 2010, approximately 3,605 terawatt-hours of energy—roughly 12.6% of U.S. total primary energy consumption—was consumed in water-related activities throughout all sectors of the economy. Most of that energy is in the form of electricity to run pumps (though some pumps operate on diesel or other fuels). Water is also treated with energy, again mostly in the form of electricity.

The heating of water is a significant energy use within buildings, and also in industrial processes—from food processing to textile manufacturing. Although solar water heaters are becoming more popular the overwhelming majority of water heating is done directly by fossil fuels (usually natural gas), or by electricity—which is often generated by fossil fuels.

Large pipes feed water at a pumped storage hydroelectric power plant. Photo credit: cobalt88/Shutterstock.com.

Meanwhile, water is essential to our current energy industry, accounting for approximately 15 percent of global water use—second only to agriculture. It is a critical resource used in drilling or mining for natural gas, coal, oil, and uranium. Resource extraction often produces wastewater, which must be treated or injected deep underground. Oil, natural gas, and uranium require refining, which again uses substantial amounts of water. Water is also used to transport coal through pipelines as a slurry—finely ground coal mixed with water.

More than 90 percent of U.S. power plants are thermoelectric, using heat from coal, natural gas, or uranium to produce steam for generating electricity. Nearly all thermoelectric plants use water cooling. After water from rivers, lakes, or seas is used for power plant cooling, it is released back into its source at a higher temperature; this thermal pollution can impact aquatic organisms.

Coal-fired, steam power plant. Photo credit: Dan Schreiber/Shutterstock.com.

Renewable energy power plants sometimes also require water (though usually much less than fossil fuel power plants). The most obvious, of course, are hydroelectric dams—by far the largest current source of renewable energy in the world. But geothermal power relies on water to convey heat within the planet’s crust to the surface, while solar panels require periodic washing to remove dust or to cool concentrated solar power systems. (With geothermal power, the permeability of “hot rock” in some situations may be increased by fracking—which brings a host of additional water pollution concerns.) There is some concern about the potential stresses of renewable energy systems on global water resources, depending on energy demand and system (in)efficiencies.

This issue will be compounded by global climate change, which is expected to increase water scarcity and extreme weather around the world. Droughts and mega-storms not only cost lives and devastate communities’ infrastructure, food systems, and livelihoods; they can also threaten electricity sources.

Example: Household Water Use

A recent study of residential water use showed that U.S. households consume roughly 88,000 gallons per year on average. Indoor household water use comes to 137 gallons per household per day, 24% of which is used just for flushing toilets. Outdoors varies greatly across the country–in California, for example, more than 50% of household water use is for landscaping.


Average daily indoor water use in the U.S. per household, based on fixtures and appliances. Toilets consume nearly a quarter of all indoor water while showers consume the largest share of hot water use. Source: Water Research Foundation, Residential End Uses of Water (Version 2).

Energy is involved in every stage of household water use—sourcing, treatment, distribution, consumption, and disposal of wastewater.

Extracting water from rivers and streams, or from underground aquifers, and then transporting it to storage facilities (often at great distances and even over hills and mountains) requires a great deal of energy, usually in the form of electricity. The water is then treated at a municipal water facility through a multi-stage process to remove debris and sedimentation, and “purify” the water by the addition of chlorine and other chemicals. Energy is used throughout this process, usually in the form of electricity, but is also embodied in the construction of facilities and the manufacture of chemicals—many of which are derived from fossil fuels.


Illustration of the water treatment process used by the Milwaukee, Wisconsin water utility agency. Image credit: Enrique Rodriguez/Milwaukee Journal Sentinel.

The water is then distributed to homes through a network of large and small pipes. Energy is used, usually in the form of electricity, to pump the water but is also embodied in the manufacturing and construction of the large network of concrete, copper, steel, iron, and PVC pipes (the last made from natural gas liquids).

On average, one-third of the water consumed indoors by households is heated. Most Americans heat their home water with a natural gas-fired tank, which keeps the water hot—usually at about 140 degrees—day and night, even when the family is away on vacation.

After water is used in the home—by flushing the toilet, washing hands, taking a shower, or running the dishwasher—the “waste water” is usually transported through a different set of pipes to a municipal waste water facility.


Sewage treatment facility. Photo credit: Kekyalyaynen/Shutterstock.com.

Wastewater goes through a complex, multi-stage process of treatment before being released back into a river or lake, or being reused. Sludge produced during these treatment steps is pumped to digesters, where it is dewatered and dried before being transported off-site for sludge disposal. Most of these stages use electricity, while the final sludge transport uses oil.


Modern communications systems send information across vast distances in massive quantities at breathtaking speeds. Every sector of the economy depends on the capture, access, and rapid transmission of information: from stock market quotes to weather forecasts; from orders for replacement parts for the electricity grid to requisitions for restocking supermarket shelves.

End-use communications devices such as computers, phones, televisions, and radios rely upon behind-the-scenes infrastructures of wires, fiber-optic cables, routers, servers, broadcasting stations and antennae, and cell towers. All of this technology represents embodied energy and requires operational energy.


Telecommunications tower. Photo credit: Jan Faukner/Shutterstock.com.

The operational energy for the U.S. telecommunications system has been estimated to account for over ten percent of the nation’s electricity use. Very little electricity may be required to operate a lightweight laptop computer, for example, but the Internet uses an average of about 5 kWh to support the transmission of every gigabyte of data.

In 2012, the global information, communication, and technology (ICT) industry was estimated to account for about two percent of the global carbon dioxide emissions—about the same as the airline industry—and that number is growing rapidly.

The embodied energy in the world’s end-use devices, cell towers, server farms, data centers, wires, and cables is also large. While operating a smartphone requires less than 4 kilowatt-hours of electricity per year, its embodied energy is estimated to be roughly 278 kWh, or 73 times its annual operational energy requirement.


The supply chain and embodied energy required to make a mobile call. Illustration from ENERGY: Overdevelopment and the Delusion of Endless Growth.

While it is feasible to produce the electricity to power and re-charge communications devices entirely from renewable sources of energy, much more challenging is substituting the use of fossil fuels for extraction and processing of raw metals, the manufacturing of devices (many parts of which are themselves petroleum by-products), and the packaging and transport of finished products.

How much energy is embodied in the entire global telecommunications system? Unfortunately, calculations are not readily available, but given the decades of energy investment in building it the number is certainly quite large. Further, of the common technological elements within the telecommunications system, those with very high embodied-to-operational energy ratios (hand-held mobile devices including phones and tablets) are the ones most frequently discarded and replaced.

Example: A Smartphone

A typical smartphone starts out as raw minerals and fossil fuels extracted from the earth. Copper, gold, palladium, and silicon were mined, requiring energy in the form of oil to operate heavy machinery and prodigious amounts of fresh water.


Truck transporting ore at copper mine. Photo credit: Gary Witton/Shutterstock.com.

The make-up of a typical smartphone is roughly 40% metals, 40% plastics (petrochemicals), and 20% ceramics and other trace materials. Over 60 different types of metals are used in the construction of a typical smartphone, including 16 of the 17 rare earth minerals. While some of these metals are used in very small amounts—for example, the indium tin oxide used to make the phone’s touchscreen—they all have to be mined using heavy equipment or, far too often, human labor.

Over 220 pounds of mine waste are generated to extract just the gold for the circuit board in a typical smartphone. And some of the most essential minerals used in modern electronics—gold, tin, tungsten, and tantalum, to name a few—come from so-called conflict areas, where inhumane conditions persist and forced labor is used.


Coltan mining in the Democratic Republic of Congo. Photo credit: Alfredo Falvo/ Contrastro/ Redux/ Newsweek.com.

Once mined, these raw resources are then refined and transported to various places in the world. A typical smartphone contains hundreds of components, each of which was individually shaped before being fitted together in an assembly plant—usually located in China.

More than 80% of the lifetime environmental impacts and primary energy demand of the phone occur during the pre-manufacturing (extraction), manufacturing, and distribution phases.


The environmental impacts of a Samsung Galaxy S® phone over its lifetime, based on twelve factors: Global warming potential, eutrophication, ozone layer depletion, photochemical oxidation, primary energy demand, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial ecotoxicity, human toxicity, water consumption, and waste generation. Source: Samsung Life-Cycle Assessment for Mobile Phones.

Altogether, far more energy is used in the manufacture of a smartphone (most of it in the form of oil) than will ever be used to operate it. Furthermore, it will likely be kept only a year or two before being replaced with a new model (the United States average smartphone replacement time is 22 months), though the device itself has an average life span of five or more years. Even more than most other computer and telecommunications equipment, smartphones are subject to the marketing strategy of planned obsolescence. Both hardware and software makers profit from rapid product replacement, enticing and eventually forcing customers to upgrade.

The operational energy for the smartphone is electricity. But these devices depend upon data servers, cell phone towers, satellites, and network relays that few users ever see. If all these are taken into account, a typical smartphone is responsible for more operational energy consumption than the refrigerator in your kitchen. The global telecommunications industry uses about 1,500 terawatt-hours of electricity annually, which works out to about ten percent of all electricity consumed.


Old mobile phone casings are discarded inside a workshop in Guiyu, China. Photo credit: Tyrone Siu/Reuters.

When a smartphone is replaced, it becomes part of the more than 42 million metric tons of electronic waste generated globally each year. The vast majority of the e-waste generated in the United States is transported via diesel-powered trucks, trains, and ships overseas, where the disassembly and recycling process mostly occurs in countries like India, Nigeria, Ghana, and the Ivory Coast, in communities that are sometimes referred to as “toxic wastelands.”